Multi-Power Garment Steamer and Control Circuit Thereof

Abstract

A control circuit includes a power switch, a heating unit, a water supply unit and a circuit module, wherein the power switch is connected to the heating unit and the water supply unit, and the heating unit and the water supply unit are connected to the circuit module, wherein the circuit module is used to adjust input voltage of different voltage environments to enable the multi-power garment steamer works normally.

Claims

1. A control circuit for a multi-power garment steamer, wherein the control circuit, which is adapted for being connected to two terminals of a power source, comprises: a power switch; a heating unit; a water supply unit; and a circuit means, wherein the power switch is connected to the heating unit and the water supply unit, and the heating unit and the water supply unit are connected to the circuit means, wherein the circuit means is used to adjust input voltage of different voltage environments to enable the multi-power garment steamer works normally.

2. The control circuit according to claim 1, wherein the heating unit comprises a first heating element and a second heating element, wherein the circuit means is configured to allow the two heating elements to be connected in series when a higher input power voltage is applied, and allow the two heating elements to be connected in parallel when a lower input power voltage is applied.

3. The control circuit according to claim 2, wherein the higher input power voltage is in the range of 220V-240V, the lower input power voltage is in the range of 100V-120V.

4. The control circuit according to claim 1, wherein the circuit means is a voltage regulating circuit comprising a working voltage selection switch and a voltage dividing resistor which is parallel to the working voltage selection switch, wherein when the working voltage selection switch is disconnected, the voltage dividing resistor is connected to the voltage regulating circuit to divide the voltage; when the working voltage selection switch is closed, the voltage dividing resistor is short-circuited, and thus is not connected to the voltage regulating circuit.

5. The control circuit according to claim 4, wherein an impedance of the voltage dividing resistor satisfies the following relationship: $z_{\mathrm{vd}}=a/\left(\frac{1}{Z_f}+\frac{1}{Z_w}\right)$ wherein Z.sub.vd denotes the impedance of the voltage dividing resistor, Z.sub.f denotes an impedance of the heating unit, and Z.sub.w denotes an impedance of the water supply unit, wherein a value range of a is [0.9, 1.1].

6. The control circuit according to claim 4, wherein an impedance of the voltage dividing resistor is equal to an overall impedance of the heating unit and the water supply unit.

7. The control circuit according to claim 1, wherein the circuit means is an automatic voltage division control circuit comprising a voltage dividing resistor, a power supply circuit, an AC voltage detection circuit, a relay control circuit, road, and an automatic voltage-dividing switch circuit, wherein the voltage-dividing resistor is connected in parallel with the automatic voltage-dividing switch circuit, the power switch is connected to the power supply circuit, and the power supply circuit is connected to the relay control circuit, the power switch is connected to the AC voltage detection circuit, and the AC voltage detection circuit is connected to the relay control circuit, the relay control circuit is in cooperation with the automatic voltage dividing switch circuit.

8. The control circuit according to claim 7, wherein the automatic voltage-dividing switch circuit comprises a relay control switch and an arc-extinguishing circuit, wherein the relay control switch is connected in parallel with the voltage dividing resistor; the arc extinguishing circuit is connected in parallel with the relay control switch.

9. The control circuit according to claim 8, wherein the arc extinguishing circuit comprises a resistor R7 and a capacitor C4, the resistance R7 is connected in series with the capacitor C4.

10. The control circuit according to claim 8, wherein the AC voltage detection circuit comprises a diode D4, a resistance R8, a resistance R9, a resistance R10 and a capacitor C5, the power switch is connected in series with the diode D4, the resistance R8 and the resistor R9, the resistance R9 is connected to the relay control circuit, the power switch is connected in series with the diode D4, the resistance R8, the resistance R9 and the resistor R10, the resistor R10 is connected to the relay control circuit, the capacitor C5 is connected in parallel with the resistor R10 at two ends thereof.

11. The control circuit according to claim 10, wherein the relay control circuit comprises an N-MOS tube Q1, a P-MOS Tube Q2, a Relay K1, a diode D3, a resistance R11 and a resistor R12, the resistance R9 is connected to a gate of the P-MOS Tube Q2; the resistance R10 is connected to a drain of the P-MOS tube Q2; a source of the P-MOS tube Q2 is connected to a gate of the N-MOS Tube Q1, a drain of the P-MOS Tube Q2 is connected to a source of the N-MOS Tube Q1, a voltage output terminal of the power supply circuit is connected to the resistor R12, the resistor R12 is connected to the gate of the N-MOS Tube Q1, the voltage output terminal of the power supply circuit is connected to the relay K1, the relay K1 is connected to the drain of the N-MOS Tube Q1, the diode D3 is reverse connected between the voltage output of the power supply circuit and the drain of the N-MOS Tube Q1, and the relay K1 is in cooperation with the automatic voltage dividing switch circuit.

12. The control circuit according to claim 1, further comprising a load circuit, a bridge rectifier module, and a MOS control circuit, the power switch is connected to the load circuit which comprises two parallel branches: a first branch connecting to the water supply unit, and a second branch connecting to the bridge rectifier module; wherein the bridge rectifier module is further connected in series with the heating unit, wherein the load circuit is connected to the MOS control circuit, and the MOS control circuit is connected to the bridge rectifier module for determining whether to disconnect the load circuit based on whether peak operating voltage exceeds a preset threshold, ensuring normal operation of the multi-power garment steamer under different power supply voltages.

13. The control circuit according to claim 1, further comprising a load circuit, a bridge rectifier module, and an MCU control circuit, wherein the power switch is connected to the load circuit which comprises two parallel branches: a first branch is in series with the water supply unit, and a second branch is connected to the bridge rectifier module and the heating unit; wherein the load circuit is connected to the MCU control circuit, which in turn is connected to the bridge rectifier module, wherein the MCU control circuit is used to determine whether to disconnect the load circuit based on whether the detected high-voltage signal exceeds a set threshold, ensuring the multi-power garment steamer operates normally under different power voltages.

14. The control circuit according to claim 4, wherein the heating unit comprises a series-connected heating element and a thermal fuse.

15. The control circuit according to claim 14, wherein the heating unit further comprises a temperature controller which is connected in series with the heating element and the thermal fuse.

16. The control circuit according to claim 4, wherein the water supply unit comprises a series-connected diode and a water pump.

17. The control circuit according to claim 7, wherein the heating unit comprises a series-connected heating element and a thermal fuse.

18. The control circuit according to claim 17, wherein the heating unit further comprises a temperature controller which is connected in series with the heating element and the thermal fuse.

19. The control circuit according to claim 7, wherein the water supply unit comprises a series-connected diode and a water pump.

20. The control circuit according to claim 2, wherein the water supply unit comprises a series-connected diode and a water pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1 is a schematic diagram of a voltage-dividing multi-power garment steamer control circuit.

[0059] FIG. 2 is a schematic diagram of a multi-power garment steamer control circuit based on automatic voltage division.

[0060] FIG. 3 is a schematic diagram of a MOS-based multi-power garment steamer control circuit.

[0061] FIG. 4 is a schematic diagram of a MCU-based multi-power garment steamer control circuit.

[0062] FIG. 5 is an exploded view of a multi-power garment steamer.

[0063] FIG. 6 is a schematic view of a heating unit of the multi-power garment steamer.

[0064] FIG. 7 is a schematic diagram of a multi-power garment steamer control circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0065] The following description is disclosed to enable any person skilled in the art to make and use the present invention. Preferred embodiments are provided in the following description only as examples and modifications will be apparent to those skilled in the art. The general principles defined in the following description would be applied to other embodiments, alternatives, modifications, equivalents, and applications without departing from the spirit and scope of the present invention.

[0066] The present invention provides a multi-power garment steamer comprising a voltage-dividing multi-power garment steamer control circuit. The voltage-dividing multi-power garment steamer control circuit is built into the multi-power garment steamer. The garment steamer control circuit enables the multi-power garment steamer to operate normally under different power supply voltages.

[0067] In order to realize the normal operation of the multi-power garment steamer under different power supply voltages, this embodiment adopts the voltage-dividing multi-power steamer control circuit, as shown in FIG. 1 which is a schematic diagram illustrating the voltage-dividing multi-power garment steamer control circuit.

[0068] In this embodiment, the voltage-dividing multi-power garment steamer control circuit comprises a power switch 12, a heating unit 13, a water supply unit 14 and a voltage regulation circuit 15. The power switch 12 is connected with the heating unit 13 and the water supply unit 14, the heating unit 13 and the water supply unit 14 is connected with the voltage regulation circuit 15 form the voltage-dividing multi-power control circuit, the control circuit is adapted for being connected to two ends of a power supply, wherein the voltage regulator circuit 15 is used to adjust the input voltage of different voltage environments to enable the multi-power garment steamer to work normally.

[0069] In this embodiment, the multi-power garment steamer control circuit based on automatic voltage division may also comprises a power supply connector 11, and the power connector 11 is used as an example to connect the two ends of the power source.

[0070] The power connector 11 comprises a first contact terminal and a second contact terminal for being electrically connected to two contacts of the power source. When the first contact terminal is connected in series with the power switch 12, and then is connected to the heating unit 13 and the water supply unit 14 which are parallel to teach other, and then the voltage regulation circuit 15 is connected, and finally back to the second contact terminal, forming the multi-power garment steamer control circuit. The voltage regulation circuit 15 is used to form different control loops based on the operation on the working voltage selection switch 152, so as to realize the normal operation of the multi-power garment steamer in different power supply voltages.

[0071] In order to ensure the operation safety of the heating unit 13, the heating unit 13 comprises a heating element 131 connected in series with a thermal fuse 132. The thermal fuse 132 can be used for protecting the garment steamer when the heating unit 13 is overheated.

[0072] In order to keep the temperature of the multi-power garment steamer at a certain level during operation, the heating unit 13 also comprises a temperature controller 133 which is in series connection with the heating element 131 and thermal fuse 132, so as to achieve temperature control.

[0073] The water supply unit 14 comprises a diode 141 and a water pump 142, the diode 141 and water pump 142 (pulse pump) may be in a series connection, the diode 141 can allow the half cycle of alternating current (sine wave) to pass by, so that the water pump 142 is powered by the power source, so as to ensure the normal operation of the water pump 142.

[0074] In this embodiment, the voltage regulating circuit 15 comprises the parallel working voltage selection switch 152 and a voltage divider resistance 151, when the working voltage selection switch 152 is disconnected, the voltage dividing resistor 151 is normally connected to the voltage-dividing multi-power garment steamer control circuit for voltage division; when the working voltage selection switch 152 is closed, the voltage dividing resistor 151 is short-circuited, and thus is not connected to the voltage-dividing multi-power steamer control circuit, and no voltage division is performed. The voltage division means that the voltage dividing resistor 151 is connected in series to the circuit, so that the voltage in the circuit is divided according to the resistance value. The series circuit distributes the voltage in the series circuit, thereby dividing a part of the voltage and reducing the voltage of other parts in the series circuit.

[0075] Then, based on the user's operation on the working voltage selection switch 152, when the working voltage selection switch 152 is disconnected, the voltage dividing resistor 151 is normally connected to the voltage-dividing multi-power steamer control circuit, so that the voltage division is performed to achieve normal operation in a high power supply voltage environment (for example 200-240V). When the working voltage selection switch 152 is closed, the voltage dividing resistor 151 is short-circuited and is not connected to the voltage-dividing multi-power garment steamer control circuit. The machine control circuit does not perform voltage division to achieve low power supply voltage operation (for example 100-120V), so that it is possible to choose components such as the water pump 142 and the heating element 131 which are able to normally operate under the power supply voltage of 120V, and the components can work normally under different power supply voltage conditions.

[0076] The impedance of the voltage dividing resistor 151 satisfies the following relationship:

[00002]$z_{vd}=a/\left(\frac{1}{Z_f}+\frac{1}{Z_w}\right)$

[0077] Wherein Z.sub.vd denotes the impedance of the voltage dividing resistor, Z.sub.f denotes the impedance of the heating unit, and Z.sub.w denotes the impedance of the water supply unit. The value range of a is [0.9, 1.1].

[0078] This embodiment uses a=1 as an example, the impedance of the voltage dividing resistor 151 is equal to the overall impedance of the heating unit 13 and the water supply unit 14, so as to play a precise voltage division role. When connecting to the power source of 220V, through the voltage dividing resistor 151, the voltage distributed to the water supply unit 14 and heating unit 13 is 110V (the two are connected in parallel), and the voltage dividing resistor 151 also is assigned with 110V voltage.

[0079] In summary, the present application provides a voltage-dividing multi-power garment steamer control circuit and a multi-power garment steamer, through a power connector 11 with its first contact terminal being connected in series with the power switch 12, then being connected to the heating units 13 and water supply unit 14 which are in a parallel connection, and then with the voltage regulation circuit 15, and finally back to the second contact terminal, s that the voltage-regulating multi-power garment steamer control circuit is formed. The voltage regulation circuit 15 is used to form different control loops based on the operation on the working voltage selection switch 152, so as to realize the normal operation of the multi-power garment steamer in different power supply voltages. The heating unit 13 comprises the heating element 131 and the thermal fuse 132 that is in series connection with the heating element 131. The thermal fuse 132 can fuse when it is overheated, so as to protect the multi-power garment steamer, and the heating unit 13 also comprises the temperature controller 133, so as to keep the temperature of the heating element 131 to be at a relatively stable level. The water supply unit 14 comprises the diode 141 and the water pump 142, the diode 141 and water pump 142 (pulse pump) may be in a series connection, the diode 141 can allow the half cycle of alternating current (sine wave) to pass by, so that the water pump 142 is powered by the power source, so as to ensure the normal operation of the water pump 142. The voltage regulating circuit 15 comprises the parallel working voltage selection switch 152 and the voltage divider resistance 151. Based on the user's operation on the working voltage selection switch 152, when the working voltage selection switch 152 is disconnected, the voltage dividing resistor 151 is normally connected to the voltage-dividing multi-power steamer control circuit, so that the voltage division is performed to achieve normal operation in a high power supply voltage environment (for example 200-240V). When the working voltage selection switch 152 is closed, the voltage dividing resistor 151 is short-circuited and is not connected to the voltage-dividing multi-power garment steamer control circuit. The machine control circuit does not perform voltage division to achieve low power supply voltage operation (for example 100-120V), so that it is possible to choose components such as the water pump 142 and the heating element 131 which are able to normally operate under the power supply voltage of 120V, and the components can work normally under different power supply voltage conditions. The impedance selection of the voltage dividing resistor 151 can be determined according to the impedance of the load, so as to achieve accurate voltage division and control the working voltage of the multi-power garment steamer.

[0080] Referring to FIG. 2, the present application provides a multi-power garment steamer based on automatic voltage division. The control circuit is built into the multi-power garment steamer, and the multi-power garment steamer is controlled by automatic voltage division. The circuit enables the multi-power garment steamer to operate normally under different power supply voltages.

[0081] In order to realize the normal operation of the multi-power garment steamer under different power supply voltages, this embodiment adopts an automatic regulating multi-power steamer control circuit based on automatic voltage division, as shown in FIG. 2 which is a schematic diagram of the multi-power garment steamer control circuit based on automatic voltage division according to an embodiment of the present application.

[0082] In this embodiment, the multi-power garment steamer control circuit based on automatic voltage division comprises a power switch 12, a load circuit and an automatic voltage division control circuit 15A, the power switch 12 is connected to the load circuit, the load circuit is connected to the automatic voltage division control circuit 15A to form the multi-power garment steamer control circuit based on automatic voltage division. The multi-power garment steamer control circuit based on automatic voltage division is connected to two ends of the power source, the control circuit connects determined circuit which enables the multi-power garment steamer to work normally based on whether the voltage peak of the input voltage exceeds a set threshold.

[0083] The multi-power garment steamer control circuit based on automatic voltage division comprises a power connector 11 which is used for connecting to two ends of the power source.

[0084] The power connector 11 comprises a first contact terminal and a second contact terminal for connecting with two ends of the power source. The first contact terminal is connected in series with the power switch 12, and then is connected to the load circuit which is connected to the automatic voltage division control circuit 15A, and finally back to the second contact terminal, so as to form the multi-power garment steamer control circuit with automatic voltage division.

[0085] The automatic voltage division control circuit 15A is able to connect the voltage dividing resistor 151A into the circuit when the peak voltage of the input working voltage exceeds the set threshold. When the peak voltage of the input working voltage does not exceed the set threshold, the automatic voltage division control circuit 15A short-circuit the voltage dividing resistor 151A, thus forming different control circuit and adjusting the working voltage of the load circuit to realize the normal operation of the multi-power garment steamer under different power supply voltages.

[0086] The load circuit comprises a heating unit 13 which is connected in parallel with a water supply unit 14. In order to ensure the safety, the heating unit 13 comprises a heating element 131 which is connected in series with a thermal fuse 132. The thermal fuse 132 will blow when overheated to protect the multi-power garment steamer.

[0087] In order to keep the temperature of the multi-power garment steamer at a certain level during operation, the heating unit 13 also comprises a temperature controller that can be connected with the heating element 131 and the thermal fuse 132 in series to achieve temperature control.

[0088] The water supply unit 14 comprises a diode 141 and a water pump 142, the diode 141 and water pump 142 (pulse pump) may be in a series connection, the diode 141 can allow the half cycle of alternating current (sine wave) to pass by, so that the water pump 142 is powered by the power source, so as to ensure the normal operation of the water pump 142.

[0089] In this embodiment, the automatic voltage division control circuit 15A comprises a voltage dividing resistor 151A, a power supply circuit 152A, an AC voltage detection circuit 153A, a relay control circuit 154A, and an automatic voltage dividing switch circuit 15A.

[0090] The voltage dividing resistor 151A is connected in parallel with the automatic voltage dividing switch circuit 155A, and the voltage dividing resistor 151A is connected between the load circuit and the second contact terminal; the first contact terminal is connected in series with the power switch 12, and then is connected with the power supply circuit 152A which is connected to the relay control circuit 154A for powering the relay; the first contact terminal is connected in series with the power switch 12, and also is connected with the AC voltage detection circuit 153A which is connected with the relay control circuit 154A; the relay control circuit 154A is cooperating with the automatic voltage dividing switch circuit 155A in a manner that the relay in the automatic voltage dividing switch circuit 155A controls the relay control switch of the automatic voltage dividing switch circuit 155A.

[0091] Exemplary, the power supply circuit 152A can be a commonly used power supply circuit in the field of small household appliances. As described above, it is sufficient to power the relay and related control circuits, wherein F1 is a fuse, R1, R2, R3, R4, R5, and R6 are resistors, R5 is a sliding resistance, D1, D2 are diodes, C1, C2, C3 are capacitors, L1 is an inductance, AC_L is an input voltage terminal of the main power. VCC is the voltage output Terminal for supplying electric power to the relay and related circuits, GND stands for grounding.

[0092] The automatic voltage-dividing switch circuit 155A comprises a relay control switch and an arc-extinguishing circuit. The relay control switch is connected in parallel with the voltage dividing resistor 151A; the arc extinguishing circuit is connected in parallel with the relay control switch. The arc extinguishing circuit comprises a resistor R7 and a capacitor C4, the resistance R7 is connected in series with the capacitor C4. The arc extinguishing circuit is primarily used to reduce the arc that may occur when disconnecting the relay control switch, thereby minimizing the impact of the arc.

[0093] The AC voltage detection circuit comprises a diode D4, a resistance R8, a resistance R9, a resistance R10 and a capacitor C5, the power switch 12 is connected in series with the diode D4, the resistance R8 and the resistor R9, the resistance R9 is connected to the relay control circuit 154A; the power switch 12 is connected in series with the diode D4, the resistance R8, the resistance R9 and the resistor R10, the resistor R10 is connected to the relay control circuit; the capacitor C5 is connected in parallel with the resistor R10 at two ends thereof.

[0094] The relay control circuit 154A comprises an N-MOS tube Q1, a P-MOS Tube Q2, a Relay K1, a diode D3, a resistance R11 and a resistor R12, the resistance R9 is connected to the gate of the P-MOS Tube Q2; the resistance R10 is connected to the drain of the P-MOS tube Q2; the source of the P-MOS tube Q2 is connected to the gate of the N-MOS Tube Q1, the drain of the P-MOS Tube Q2 is connected to the source of the N-MOS Tube Q1. The voltage output terminal of the power supply circuit is connected to the resistor R12, the resistor R12 is connected to the gate of the N-MOS Tube Q1. The voltage output terminal of the power supply circuit is connected to the relay K1, the relay K1 is connected to the drain of the N-MOS Tube Q1, the diode D3 is reverse connected between the voltage output of the power supply circuit and the drain of the N-MOS Tube Q1, and the relay K1 is in cooperation with the automatic voltage dividing switch circuit in a manner that the relay K1 controls the relay control switch in the automatic voltage dividing switch circuit. The drain of the P-MOS transistor Q2 is connected to ground.

[0095] Base on this circuit design, in the AC voltage detection circuit 153A, when the voltage on the live wire is positive, a low-voltage DC signal is obtained that increases as the mains voltage rises through voltage division and rectification via diode D4, resistor R8, resistor R9, and resistor R10, while simultaneously charging capacitor C5. When the voltage on the live wire is negative, due to the unidirectional conduction characteristic of diode D4, the loop formed by diode D4, resistor R8, resistor R9, resistor R10, and the neutral and live wires is not connected. The voltage across resistor R10 is maintained at a stable value by the discharge of capacitor C5, ensuring that the gate voltage (G) of P-MOS transistor Q2 does not fluctuate with the AC voltage variations. When the peak value of the input mains voltage does not exceed the set threshold (e.g., 163V), the low-voltage DC signal from the voltage division and rectification in the AC voltage detection circuit 153A remains below the gate threshold voltage of P-MOS transistor Q2. Thus, the drain and source of P-MOS transistor Q2 are not conducting. Due to the pull-up resistor on resistor R12, the gate of N-MOS transistor Q1 remains at a high level, allowing the drain and source of N-MOS transistor Q1 to conduct. This energizes the load side of relay K1, causing the relay control switch in the automatic voltage division switch circuit 155A to close, allowing the garment steamer to operate normally without voltage division, as voltage divider resistor 151A is short-circuited. When the input mains voltage exceeds the set threshold (e.g., 163V), the low-voltage DC signal from the voltage division and rectification in the AC voltage detection circuit 153A exceeds the gate threshold voltage of P-MOS transistor Q2, causing the drain D and source of P-MOS transistor Q2 to conduct. This pulls the gate of N-MOS transistor Q1 to a low level, preventing conduction between its drain and source, thus disconnecting the load side of relay K1. The relay control switch in the automatic voltage division switch circuit 155A opens, allowing the voltage dividing resistor 151A to connect into the circuit and participate in the voltage division. The resistive load and voltage dividing resistor 151A work together, ensuring that the voltage supplied to the garment steamer is limited within the rated voltage range, thereby ensuring its normal operation. By adjusting the resistance value of resistor R10, different threshold values can be set.

[0096] The present application provides a multi-power garment steamer and a control circuit thereof. The first contact terminal of the power connector is connected in series with the power switch 12, and then is connected to the load circuit which is connected to the automatic voltage division control circuit 15A, and finally back to the second contact terminal, so as to form the multi-power garment steamer control circuit with automatic voltage division. The first contact terminal is connected in series with the power switch 12, and also is connected with the AC voltage detection circuit 153A which is connected with the relay control circuit 154A; the relay control circuit 154A is cooperating with the automatic voltage dividing switch circuit 155A in a manner that the relay in the automatic voltage dividing switch circuit 155A controls the relay control switch of the automatic voltage dividing switch circuit 155A. The automatic voltage division control circuit 15A is able to connect the voltage dividing resistor 151A into the circuit when the peak voltage of the input working voltage exceeds the set threshold. When the peak voltage of the input working voltage does not exceed the set threshold, the automatic voltage division control circuit 15A short-circuit the voltage dividing resistor 151A, thus forming different control circuit and adjusting the working voltage of the load circuit to realize the normal operation of the multi-power garment steamer under different power supply voltages

[0097] Based on this circuit design, in the AC voltage detection circuit 153A, when the voltage on the live wire is positive, a low-voltage DC signal is generated, which increases as the mains voltage rises through voltage division and rectification via the diode D4, the resistor R8, the resistor R9, and the resistor R10, and this signal simultaneously charges the capacitor C5. When the voltage on the live wire is negative, due to the unidirectional conduction characteristic of the diode D4, the circuit formed by the diode D4, the resistor R8, the resistor R9, the resistor R10, and the neutral and live wires is not connected. The voltage across resistor R10 is maintained at a stable value by the discharge of the capacitor C5, ensuring that the gate voltage of P-MOS transistor Q2 does not fluctuate with the AC voltage changes. When the peak value Umax of the input mains voltage does not exceed the set threshold (e.g., 163V), the low-voltage DC signal from the voltage division and rectification in the AC voltage detection circuit 153A remains below the gate threshold voltage of P-MOS transistor Q2. Thus, the drain and source of P-MOS transistor Q2 are not conducting. Due to the pull-up resistor on resistor R12, the gate of N-MOS transistor Q1 remains at a high level, allowing the drain and source of N-MOS transistor Q1 to conduct. This energizes the load side of relay K1, causing the relay control switch in the automatic voltage division switch circuit 155A to close, allowing the garment steamer to operate normally without voltage division, as voltage divider resistor 151A is short-circuited. When the input mains voltage exceeds the set threshold (e.g., 163V), the low-voltage DC signal from the voltage division and rectification in the AC voltage detection circuit 153A exceeds the gate threshold voltage of P-MOS transistor Q2, causing the drain and source of P-MOS transistor Q2 to conduct. This pulls the gate of N-MOS transistor Q1 to a low level, preventing conduction between its drain and source, thus disconnecting the load side of relay K1. The relay control switch in the automatic voltage division switch circuit 155A opens, allowing voltage dividing resistor 151A to connect into the circuit and participate in the voltage division. The resistive load and voltage dividing resistor 151A work together, ensuring that the voltage supplied to the garment steamer is limited within the rated voltage range, thereby ensuring its normal operation. By adjusting the resistance value of resistor R10, different threshold values can be set.

[0098] The heating unit 13 includes the heating element 131 and the thermal fuse 132, wherein the thermal fuse 132 can blow during overheating to protect the multi-power garment steamer. The heating unit 13 can also include the temperature controller to maintain a relatively stable temperature for the heating element 131. In the water supply unit 14, the diode is connected in series with the water pump 142 (a pulse pump), and the diode allows half of the AC (sine wave) cycle to pass, powering the water pump 142 to ensure its normal operation. When the relay control switch in the automatic voltage division switch circuit 155A is open, the voltage dividing resistor 151A is connected into the circuit to perform voltage division, enabling normal operation under high mains voltage conditions (e.g., reducing from 200-240V to 100-120V after division). When the relay control switch is closed, the voltage dividing resistor 151A is short-circuited and not connected into the circuit, allowing operation under low mains voltage conditions (e.g., 100-120V). This allows the selection of components suitable for operation under 120V, ensuring the multi-power garment steamer can function properly under different mains voltage conditions.

[0099] The impedance of voltage dividing resistor 151A is selected based on the impedance of the load, ensuring precise voltage division and controlling the operating voltage of the multi-power garment steamer.

[0100] Referring to FIG. 3, which shows a schematic diagram of the MOS-based multi-power garment steamer control circuit provided by the embodiment of this application. In this embodiment, the MOS-based multi-power garment steamer control circuit comprises a power connector 11, a power switch 12, a load circuit, a bridge rectifier module 15B, and a MOS control circuit 16.

[0101] The power switch 12 is connected to the load circuit which comprises two parallel branches: a first branch is connected in series to the water supply unit 14, and a second branch is connected to the bridge rectifier module 15B. The bridge rectifier module 15B is connected in series to the heating unit 13. The load circuit is connected to the MOS control circuit 16, which in turn is connected to the bridge rectifier module 15B, forming the MOS-based multi-power garment steamer control circuit. The MOS control circuit 16 is used to determine whether to disconnect the load circuit based on whether the peak working voltage exceeds a set threshold, enabling the garment steamer to operate normally under different power supply voltages.

[0102] As an example, the power connector 11 may comprise a first contact terminal (i.e., one terminal of the power supply) and a second contact terminal (the other terminal of the power supply). The first contact terminal is connected in series with the power switch 12, which is then connected to the two parallel branches: the first branch connects in series to the water supply unit 14, and the second branch connects to the bridge rectifier module 15B, which is then connected in series to the heating unit 13. After the first and second branches converge, they form the load circuit. The load circuit connects to the MOS control circuit 16, which connects to the bridge rectifier module 15B and then returns to the second contact terminal, forming the MOS-based multi-power garment steamer control circuit.

[0103] The MOS control circuit 16 is designed to disconnect the load circuit from the second contact terminal when the peak working voltage exceeds the set threshold and to maintain the connection between the load circuit and the second contact terminal when the peak voltage does not exceed the threshold. Thus, by using the MOS control circuit 16, the MOS-based multi-power garment steamer control circuit can disconnect the load circuit when the peak voltage exceeds the threshold and maintain the connection when the peak voltage is within the threshold. This enables the system to utilize the characteristics of the AC sine wave (periodic gradual increase and decrease) to allow the load circuit to operate when the peak voltage is below the set threshold and stop when it exceeds it. Under low-voltage conditions, wherein the peak voltage at any time does not exceed the set threshold, the system can operate normally.

[0104] First, the bridge rectifier module 15B comprises four diodes (high-current diodes) and has two power terminals (opposite sides, each separated by two diodes) and two load terminals (opposite sides, each separated by two diodes), arranged in a sequence of the first power terminal, first load terminal, second power terminal, and second load terminal. After the first contact terminal is connected to the power switch 12, it is connected to the first power terminal, while the second contact terminal is connected to the second power terminal. The MOS control circuit 16 is connected between the first and second load terminals, and the heating unit 13 is connected between the first load terminal and the MOS control circuit 16.

[0105] The MOS control circuit 16 includes a voltage regulation circuit (named for distinction, not to limit its function), a step-down circuit (also named for distinction), and an N-type MOS transistor.

[0106] The voltage regulation circuit contains a voltage regulator (for example, TL431), with the reference pin of the voltage regulator connected in series with resistors and then to the first load terminal of the bridge rectifier module 15B. The cathode of the voltage regulator is connected to the gate of the N-type MOSFET, and the anode is connected to the drain of the N-type MOSFET.

[0107] Specifically, the voltage regulation circuit may comprise the voltage regulator, resistors R13, R16, R19, and capacitor C8. The first load terminal of the bridge rectifier module 15B connects in series to resistors R13 and R16 and then to the reference pin of the voltage regulator. After resistor R19 is connected in series, it connects to the anode of the voltage regulator. Capacitor C8 is connected in parallel with resistor R19, forming an RC filter circuit. The cathode of the voltage regulator connects to the gate of the N-type MOS transistor, while the anode connects to the drain of the N-type MOS transistor.

[0108] The resistance values for R13 and R16 are both 510K, and the value for R19 can be calculated based on the set threshold and the 2.5V reference voltage in the voltage regulator (i.e., the reference threshold)

[0109] Using a load rated at 120V (frequency 60 Hz) and supplied with 220V, 50 Hz as an example, perform the following calculations.

[00003]$\mathrm{Heat}\mathrm{generation}:Q=I2\mathrm{Rt}=u2*t/R$

[0110] Heat generation within 1 second under 120V AC power, peak voltage u.sub.max1=120*{square root over (2)}.sup.V, frequency f.sub.1=60 Hz:

[00004]$Q_1=2*f_1*{}_0^{}{u}_{\max 1}^2*\sin 2\left(x\right)\mathrm{dx}/R=f_1*u_{\max 1}^2/R$

[0111] Based on the circuit and the symmetric characteristics of the sine wave, heat generated within 1 second under 120V AC power, peak voltage u.sub.max2=220*{square root over (2)}.sup.V, frequency f.sub.2=50 Hz:

[00005]$Q2=2*f_2*2*{}_0^{}{u}_{\max 2}^2*\sin 2\left(x\right)\mathrm{dx}/R$

[0112] Setting Q1=Q2, solving for a0.8105, corresponding to a voltage of 225.45V, while keeping R13 and R16 unchanged, given that the reference voltage is 2.5V, using resistor voltage division calculation to obtain the value of R9 which is approximately 11.4 K:

[00006]$2.5=225.45*R19/\left(R13+R16+R19\right)$

[0113] The first end of the step-down circuit is connected to the first load connection terminal of the bridge rectifier module 15B, while the second end of the step-down circuit is connected to the gate of the N-type MOS transistor. After passing through an RC filter, the second end of the step-down circuit is further connected to the drain of the N-type MOS transistor.

[0114] Specifically, the step-down circuit comprises resistors R14, R17, R18, and capacitor C7. The first load connection terminal of the bridge rectifier module 15B is connected in series with resistor R14 and resistor R17, which is then connected to the gate of the N-type MOS transistor. Additionally, the first load connection terminal of the bridge rectifier module 15B is connected in series with resistor R14, resistor R17, and resistor R18, which is then connected to the drain of the N-type MOS transistor. Furthermore, capacitor C7 is connected in parallel with resistor R18, forming an RC filter circuit. For example, the resistance values of resistor R14 and resistor R17 are both 510K, and resistor R18 has a resistance value of 10K.

[0115] As for the N-type MOS transistor, its source is connected to the load circuit, and its drain is connected to the second load connection terminal of the bridge rectifier module 15B. Additionally, the drain of the N-type MOS transistor is connected to ground.

[0116] Therefore, when the reference terminal of the voltage regulator provides a voltage higher than the reference threshold (the reference threshold of 2.5V is the value corresponding to the set threshold after being stepped down by the voltage regulation circuit; a voltage higher than the reference threshold indicates that the input voltage exceeds the set threshold), the voltage regulator conducts between its anode and cathode, thereby lowering the voltage of the N-type MOS transistor. This causes the drain and source of the N-type MOS transistor to disconnect, thereby breaking the entire load circuit and causing the load circuit to stop operating. When the input voltage is below the set threshold (at this time, the voltage provided by the reference terminal is less than 2.5V), the load circuit resumes operation, thereby reliably enabling the multi-power garment steamer to operate normally under different power supply voltages.

[0117] To ensure the safety of the heating unit 13, the heating unit 13 can comprise a series-connected heating element 131 and a thermal fuse 132. The thermal fuse 132 can blow in case of overheating, thereby protecting the multi-power garment steamer.

[0118] To maintain a certain temperature level during the operation of the multi-power garment steamer, the heating unit 13 also comprises a temperature controller 133. The temperature controller 133 is connected in series with the heating element 131 and the thermal fuse 132, enabling temperature control.

[0119] The water supply unit 14 can comprise a diode 141 and a water pump 142. The diode 141 and the water pump 142 (pulse pump) in the water supply unit 14 are connected in series. The diode 141 allows half a cycle of the AC (sine wave) to pass through, powering the water pump 142 to ensure its normal operation, thus eliminating the need for rectification.

[0120] The bridge rectifier module 15B comprises four high-current diodes for rectifying the AC waveform into a unidirectional waveform to facilitate MOS transistor control. The MOS control circuit 16 comprises a voltage regulation circuit, a step-down circuit, and an N-type MOS transistor. The step-down circuit comprises resistors R14, R17, R18, and capacitor C7 for forming a simple step-down voltage regulation source, providing a stable drive voltage to the gate of the N-type MOS transistor, ensuring that the gate voltage of Q3 is below 20V, preferably around 10V. The voltage regulation circuit includes a voltage regulator, resistors R13, R16, R19, and capacitor C8, with C8 and R19 forming an RC filter circuit according to the designed circuit connection scheme.

[0121] Based on the definition of the AC effective value and the principle of equal heat power within a unit time, when the reference terminal of the voltage regulator provides a voltage higher than the reference threshold (the reference threshold of 2.5V is the value corresponding to the set threshold after being stepped down by the voltage regulation circuit; a voltage higher than the reference threshold indicates that the input voltage exceeds the set threshold), the voltage regulator conducts between its anode and cathode, thereby lowering the voltage of the N-type MOS transistor. This causes the drain and source of the N-type MOS transistor to disconnect, thereby breaking the entire load circuit and causing the load circuit to stop operating. When the input voltage is below the set threshold (at this time, the voltage provided by the reference terminal is less than 2.5V), the load circuit resumes operation. By reasonably adjusting the resistance values of R13, R16, and R19 based on the principle of equal heat generation, the voltage value is set, and resistor R19 is calculated to have a resistance value of 11.4 K. This reliably enables the multi-power garment steamer to operate normally under different power supply voltages.

[0122] The present application further provides a multi-power garment steamer, a multi-power garment steamer control circuit based on an MCU is embedded in the multi-power garment steamer. The multi-power garment steamer can operate normally under different power voltages through the MCU-based control circuit.

[0123] Referring to FIG. 4, which shows a schematic diagram of the MCU-based multi-power garment steamer control circuit provided in this embodiment. In this embodiment, the MCU-based control circuit of the multi-power garment steamer may comprise a power connector 11, a power switch 12, a load circuit, a bridge rectifier module 15C, and an MCU control circuit 16.

[0124] The power switch 12 is connected to the load circuit which includes a first branch and a second branch in parallel. The first branch has a water supply unit 14 in series, and the second branch connects the bridge rectifier module 15C and the heating unit 13. The load circuit is connected to the MCU control circuit 16, which is also connected to the bridge rectifier module 15C, forming the MCU-based control circuit for the multi-power garment steamer. The MCU control circuit 16 is used to determine whether to disconnect the load circuit based on whether the detected high-voltage signal exceeds the set threshold, allowing the garment steamer to operate normally under different power voltages.

[0125] For example, the power connector 11 may include a first contact terminal (connected to one power terminal) and a second contact terminal (connected to the other power terminal). After the first contact terminal is connected to the power switch 12, it connects to the load circuit. The load circuit includes a first branch in parallel with the second branch, wherein the water supply unit 14 is in series with the first branch, and the bridge rectifier module 15C is connected to the second branch in series with the heating unit 13. The load circuit connects to the MCU control circuit 16, and through the bridge rectifier module 15C, it returns to the second contact terminal, forming the MCU-based multi-power garment steamer control circuit.

[0126] The MCU control circuit 16 is used to detect the rectified high-voltage signal. When the high-voltage signal exceeds the set threshold, the connection between the load circuit and the second contact terminal is disconnected. When the high-voltage signal does not exceed the set threshold, the connection is maintained. Therefore, using the MCU control circuit 16, the MCU-based garment steamer control circuit can maintain the load circuit operation under high-voltage power conditions as long as the rectified peak voltage at the current moment does not exceed the set threshold. If the rectified peak voltage exceeds the threshold, the load circuit stops working. Under low-voltage power conditions, the peak voltage at any given moment usually does not exceed the set threshold, allowing normal operation. This design allows the multi-power garment steamer to work normally under different power voltage conditions by selecting components that meet the set power voltage requirements.

[0127] First, the bridge rectifier module 15C comprises four diodes (high-current diodes) and has two power connection terminals (opposite sides, each spaced between two diodes) and two load connection terminals (also opposite sides, each spaced between two diodes). The first power connection terminal connects to the first contact terminal after the power switch 12, and the second power connection terminal connects to the second contact terminal. The MCU control circuit 16 is connected between the first load connection terminal and the second load connection terminal, and the heating component 13 is connected between the first load connection terminal and the MCU control circuit 16.

[0128] The MCU control circuit 16 may comprise an MCU controller 161, a DC high-voltage detection circuit 162, a power supply circuit 163, a switch control circuit 164, and a diode.

[0129] After the first load connection terminal of the bridge rectifier module 15C is connected in series with a diode, it connects to the DC high-voltage detection circuit 162, which is connected to the MCU controller 161 to detect the rectified high-voltage signal. For example, the DC high-voltage detection circuit 162 can divide the high-voltage rectified from the mains power using multiple resistors (voltage dividing resistor), and the MCU controller 161 can collect the voltage V on the sampling resistor for ADC conversion, selecting the maximum value Vmax as the high-voltage signal (the corresponding set threshold is a DC voltage signal). It can also calculate the current peak value of the mains power for comparison with the set threshold (which corresponds to an AC voltage signal after conversion):

[00007]$U_{\max }=V_{\max }*\left(R_{\mathrm{sample}}+R_{\mathrm{divider}}\right)/R_{\mathrm{sample}}$

[0130] U.sub.max is the detected peak value of the mains power, V.sub.max is the high-voltage signal, R.sub.sample is the sampling resistor, and R.sub.divider is the divider resistor.

[0131] The power supply circuit 163 connects to the MCU controller 161 to supply power to it, either from an external DC power supply or internally. When powered internally, the first load connection terminal of the bridge rectifier module 15C is connected in series with a diode to the power supply circuit 163. After voltage reduction, it connects to the VCC port of the MCU controller 161, supplying power.

[0132] The MCU controller 161 generates a control signal based on the comparison between the detected high-voltage signal and the set threshold. When the high-voltage signal exceeds the threshold, the control signal disconnects the circuit; otherwise, it maintains the connection. Many models of MCU controllers are available, and appropriate components can be selected as needed.

[0133] The switch control circuit 164 connects the load circuit and the second load connection terminal of the bridge rectifier module 15C and is used to control the connection and disconnection between the load circuit and the second load connection terminal based on the control signal from the MCU controller 161. One end of the switch control circuit 164 connected to the first load connection terminal of the bridge rectifier module 15C is grounded. The switch control circuit 164 can be a relay circuit, a thyristor control circuit, an MOS transistor control circuit, an IGBT control circuit, or another type of weak-current control for a strong-current switch circuit.

[0134] To facilitate understanding, an explanation of the set threshold for the high-voltage signal is provided. For illustration, this explanation uses the set threshold for the converted AC voltage signal as an example

[0135] Using a load rated at 120V (frequency 60 Hz) and supplied with 220V, 50 Hz as an example, perform the following calculations.

[00008]$\mathrm{Heat}\mathrm{generation}:Q=I2\mathrm{Rt}=u2*t/R$

[0136] Heat generation within 1 second under 120V AC power, peak voltage u.sub.max1=120*{square root over (2)}.sup.V, frequency f.sub.1=60 Hz:

[00009]$Q_1=2*f_1*{}_0^{}{u}_{\max 1}^2*\sin 2\left(x\right)\mathrm{dx}/R=f_1*u_{\max 1}^2/R$

[0137] Based on the circuit and the symmetric characteristics of the sine wave, heat generated within 1 second under 120V AC power, peak voltage u.sub.max2=220*{square root over (2)}.sup.V, frequency f.sub.2=50 Hz:

[00010]$Q2=2*f_2*2*{}_0^{}{u}_{\max 2}^2*\sin 2\left(x\right)\mathrm{dx}/R$

[0138] Setting Q1-Q2, solving for a0.8105, correspondingly, the voltage is 225.45V, the set threshold is established at 225.45V (this is U.sub.max, the converted AC voltage signal). If a DC voltage signal is to be used as the set threshold, the following formulas need to be applied:

[00011]$V_{\max }=U_{\max }*R_{\mathrm{sample}}/\left(R_{\mathrm{sample}}+R_{\mathrm{divider}}\right)$

[0139] To ensure the safety of the heating element 13, it comprises a heating 131 and a thermal fuse in series. If the heating element 131 overheats, the thermal fuse 132 will melt, protecting the garment steamer. To maintain the garment steamer at a consistent temperature, the heating unit 13 is provided with a temperature controller 133 which is connected in series with the heating element 131 and the thermal fuse to control the temperature.

[0140] The water supply unit 14 can comprise a diode 141 and a water pump 142. The diode 141 allows only half of the AC sine wave to pass through, supplying power to the water pump 142 to ensure its normal operation. Thus, rectification is not required for the water pump.

[0141] In summary, this embodiment provides an MCU-based multi-power source garment steamer control circuit and garment steamer. By using the MCU control circuit 16, the circuit can detect the high-voltage signal after rectification and determine whether the load circuit should operate. When the signal exceeds the threshold, the load circuit is disconnected; when it does not exceed the threshold, the load circuit remains connected. This allows the garment steamer to work normally under both high and low voltage power supplies.

[0142] In summary, the present application provides an MCU-based multi-power steam iron control circuit and a multi-power garment steamer. By connecting the first contact piece of the power connector 11 in series with the power switch 12, the load circuit is connected. The load circuit includes a first branch (with a water supply unit 14 in series) and a second branch (which connects to a bridge rectifier module 15C and then the heating unit 13). The load circuit is connected to the MCU control circuit 16, which then returns to the second contact piece via the bridge rectifier module 15C, forming an MCU-based multi-power garment steamer control circuit. By adopting the MCU control circuit 16, the high-voltage signal rectified from the working voltage can be detected by the DC high-voltage detection circuit 162. The MCU controller 161 compares the detected high-voltage signal with a preset threshold. Based on the comparison result, the controller generates a corresponding control signal. If the high-voltage signal exceeds the preset threshold, the control signal disconnects the circuit; otherwise, the circuit remains connected. The switch control circuit 164 connects to both the MCU controller 161 and the load circuit, as well as the second load connection terminal of the bridge rectifier module 15C, enabling the connection and disconnection between the load circuit and the rectifier module according to the MCU control signal. Thus, under high-voltage power conditions, utilizing the periodic rise and fall characteristics of the AC sine wave, the load circuit will continue to operate when the current rectified peak voltage does not exceed the preset threshold. However, when the rectified peak voltage exceeds the threshold, the load circuit will stop functioning. Under low-voltage power conditions, the rectified peak voltage typically does not exceed the preset threshold at any given time, allowing normal operation. Therefore, this MCU-based control circuit ensures that the steam iron can function correctly under different power voltages by selecting components that can operate within the specified voltage range.

[0143] The heating unit 13 comprises the heating component 131 in series with the temperature fuse 132 and the temperature controller. The temperature fuse 132 will blow under overheating conditions, protecting the garment steamer, while the temperature controller 133 maintains a relatively stable temperature for the heating element 131. The water supply unit 14 comprises the diode and the water pump 142 (pulse pump) in series, allowing half the AC sine wave to power the pump, ensuring normal operation without the need for rectification. The bridge rectifier module 15C comprises four high-current diodes, which rectify the AC waveform into a unidirectional waveform for powering and MCU control. The power supply circuit 163 in the MCU control circuit 16 steps down the high-voltage current to power the MCU (or an external power source can be used). The zero-crossing detection circuit 165 detects when the AC voltage reaches 0V and controls the switching of high-power loads at that moment to avoid electrical arcing and reduce interference with the AC network, thus improving EMC. Zero-crossing detection can be implemented using components such as optocouplers, transistors, or MOS transistors.

[0144] Referring to FIG. 5 to FIG. 7 of the drawings, a multi-power garment steamer and its control circuit according to another preferred embodiment of the present application is illustrated. The control circuit comprises the above power connector 11, the power switch 12, the heating unit 13, and the water supply unit 14. The multi-power garment steamer comprises a housing 20, a water tank 30 and the control circuit.

[0145] The housing 20 comprises a base housing portion 21 and a head housing portion 22 transversely extended from the base housing portion 21, the water tank 30 is detachably coupled to the base housing portion 21 in a side-by-side manner, so as to form a handle part of the handheld garment steamer of the present invention, the rest part connected to the handle part forms a head part.

[0146] The side-by-side configuration of the water tank 30 with the base housing portion 21 creates a more ergonomic handle part. The width and shape of the water tank 30 contribute to a comfortable grip. In addition, the positioning of the water tank 30 allows for increased storage capacity while maintaining a compact design, meaning the user can steam longer without needing to refill.

[0147] In this embodiment, the integration of the water tank 30 into the handle part ensures a compact, streamlined design, eliminating the need for a separate bulky handle. This keeps the handheld garment steamer light and easy to maneuver. The design of the water tank 30, coupled with the base housing portion 21, provides a sturdy, well-balanced grip. This is especially important for long steaming sessions or when steaming vertically. An upper portion of the water tank 30 is formed with a concave groove 34, so as to be ergonomically conforming to the fingers of the hand of the user which is gripped on the upper portion of the water tank 30.

[0148] More specifically, the water tank 30 comprises a tank body 31 and a seat tank portion 32 connected to a lower portion of the tank body 31 to define a water storing cavity 33. A length of the tank body 31 is larger than a length of the seat tank portion 32. The base housing portion 21 of the housing 20 is seated and supported on the seat tank portion 32 when the water tank 30 is assembled with the base housing portion 21 of the housing 11. An upper portion of the tank body 31 cooperated with the base housing portion 21 of the housing 20 for a holding hand of the user to hold thereon.

[0149] More specifically, as shown in FIG. 7, in this embodiment, the heating unit 13 comprises a first heating element 1311 and a second heating element 1312, a first end of first heating element 1311 is connected to the AC_N terminal, and the second end of first heating element 1311 is connected to the AC_L terminal through the normally open contact of relay K1. The first end of second heating element 1312 is connected to the second end of first heating element 1311, while the second end of second heating element 1312 is connected to the AC_N terminal through the normally closed contact of relay K2 and connected to the AC_L terminal through the normally open contact of relay K2. Preferably, the resistances of the first heating element 1311 and the second heating element 1312 are identical.

[0150] As an example, relay K1 is a single-pole single-throw (SPST) normally open relay, and relay K2 is a single-pole double-throw (SPDT) relay. It should be understood that the types of relays K1 and K2 are not limited to these types; any relays that can perform the circuit switching function can be used as the relay switches in this application.

[0151] The first terminal of relay K1 is connected to VCC, and the second terminal is connected to the control terminal Heart1_C via the switching circuit Q1. The first terminal of relay K2 is connected to VCC, and the second terminal is connected to the control terminal Heart2_C via the switching circuit Q2.

[0152] Specifically, control terminals Heart1_C and Heart2_C are used to indicate the type of input power voltage. When 120V power is connected, Heart1_C outputs a high level of 1, and Heart2_C outputs a low level of 0. When 240V power is connected, Heart1_C outputs a low level of 0, and Heart2_C outputs a high level of 1. That is, for 120V input, Heart1_C and Heart2_C output (1,0), and for 240V input, they output (0,1). When no power is connected, Heart1_C and Heart2_C output (0,0).

[0153] As an example, the switching circuits Q1 and Q2 are N-channel MOS transistors.

[0154] During operation, with a 120V power input, Heart1_C and Heart2_C output (1,0). Since Heart1_C outputs 1, MOS transistor Q1 conducts, and relay K1 is activated, closing the contact, i.e., K1 switches from normally open to closed. Since Heart2_C outputs 0, MOS transistor Q2 remains off, and relay K2 stays in the normally closed state. At this point, first heating element 1311 and second heating element 1312 are connected in parallel between AC_N and AC_L.

[0155] Furthermore, with a 240V power input, Heart1_C and Heart2_C output (0,1). Since Heart1_C outputs 0, MOS transistor Q1 is off, and relay K1 opens its contact, returning K1 to its normally open state. Since Heart2_C outputs 1, MOS transistor Q2 conducts, and Relay K2 switches from normally closed to normally open. At this point, first heating element 1311 and second heating element 1312 are connected in series between AC_N and AC_L.

[0156] This control circuit allows the two heating elements 1311 and 1312 to be connected in series when a higher input power voltage is applied, reducing the current in the control circuit and preventing an increase in total power. Conversely, when a lower input power voltage is applied, the two heating elements 1311 and 1312 are connected in parallel, increasing the current in the control circuit and preventing a decrease in total power. As a result, the total power of the control circuit remains constant.

[0157] One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.

[0158] It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and are subject to change without departure from such principles. Therefore, this invention comprises all modifications encompassed within the spirit and scope of the following claims.