WIDE-RANGE POSITIVE-NEGATIVE ADJUSTABLE HIGH-VOLTAGE DC POWER SUPPLY AND THE CONTROL METHOD THEREOF

Abstract

A wide-range positive-negative adjustable high-voltage DC power supply includes the following components: a high-voltage generator, a negative high-voltage terminal, and a positive high-voltage terminal; a first driving circuit, a first voltage regulating unit, a current detection and amplification circuit, a second driving circuit and a second voltage regulating unit that are connected in turn; and an adjustable high-voltage output terminal; as well as an instruction input terminal, an instruction voltage circuit and an error amplifier that are connected in turn, and a voltage feedback circuit.

Claims

1. A wide-range positive-negative adjustable high-voltage DC power supply, comprising the following components: a high-voltage generator, a negative high-voltage terminal, a positive high-voltage terminal, a first driving circuit, a first voltage regulating unit, a current detection and amplification circuit, a second driving circuit, a second voltage regulating unit and an adjustable high-voltage output terminal; as well as an instruction input terminal, an instruction voltage circuit, an error amplifier and a voltage feedback circuit; wherein the high-voltage generator is respectively connected to the positive high-voltage terminal and the negative high-voltage terminal, the positive high-voltage terminal is connected to the input terminal of the first voltage regulating unit, the negative high-voltage terminal is connected to the input terminal of the second voltage regulating unit, the output terminal of the first voltage regulating unit is connected to the output terminal of the second voltage regulating unit and then to the adjustable high-voltage output terminal, the output terminal of the first driving circuit is connected to the driving terminal of the first voltage regulating unit, the current detection terminal of the first voltage regulating unit is connected to the detection input terminal of the current detection and amplification circuit, the output terminal of the current detection and amplification circuit is connected to the input terminal of the second driving circuit, and the output terminal of the second driving circuit is connected to the driving terminal of the second voltage regulating unit; the instruction input terminal, the instruction voltage circuit and the error amplifier are connected in turn, wherein the output terminal of the error amplifier is connected to the input terminal of the first driving circuit, the input terminal of the voltage feedback circuit is respectively connected to the output terminal of the first voltage regulating unit and the output terminal of the second voltage regulating unit, and the output terminal of the voltage feedback circuit is connected to the error amplifier.

2. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, wherein the first voltage regulating unit comprises m PNP transistors Q1-1, Q1-2, . . . Q1-m, m+1 resistors R1-0, R1-1, R1-2, . . . R1-m, and one Zener diode D1-1; it also comprises an input terminal, an output terminal, a current detection terminal and a driving terminal; wherein m1 and m is an integer; collectors and emitters of the m PNP transistors are connected to each other in series in turn, wherein the emitter of the first transistor Q1-1 is connected to the anode of the Zener diode D1-1, the cathode of the Zener diode D1-1 is connected to one electrode of the current detection terminal of the first voltage regulating unit, the other electrode of the current detection terminal is connected to the input terminal of the first voltage regulating unit, one terminal of the resistor R1-0 is connected to one electrode of the driving terminal of the first voltage regulating unit, the other electrode of the driving terminal is connected to the input terminal of the first voltage regulating unit, the other terminal of the resistor R1-0 is connected to the base of the PNP transistor Q1-1, the two terminals of the resistor R1-m are respectively connected to the base and collector of the transistor Q1-m, the collector of the transistor Q1-m is also connected to the output terminal of the first voltage regulating unit, and the remaining m1 resistors are respectively connected across the bases of the m transistors connected in series in turn.

3. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, wherein the second voltage regulating unit comprises n NPN transistors Q2-1, Q2-2, . . . Q2-n, n+1 resistors R2-0, R2-1, R2-2, . . . R2-n, and one Zener diode D2-1; it also comprises an input terminal, an output terminal and a driving terminal; wherein n1 and n is an integer; collectors and emitters of the n NPN transistors are connected to each other in series in turn, wherein the emitter of the first transistor Q2-1 is connected to the cathode of the Zener diode D2-1, the anode of the Zener diode D2-1 is connected to the input terminal of the second voltage regulating unit, one terminal of the resistor R2-0 is connected to one electrode of the driving terminal of the second voltage regulating unit, the other electrode of the driving terminal is connected to the input terminal of the second voltage regulating unit, the other terminal of the resistor R2-0 is connected to the base of the NPN transistor Q2-1, the two terminals of the resistor R2-n are respectively connected to the base and collector of the transistor Q2-n, the collector of the transistor Q2-n is also connected to the output terminal of the second voltage regulating unit, and the remaining n1 resistors are respectively connected across the bases of the n transistors connected in series in turn.

4. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, wherein the first driving circuit comprises one transistor Q3-1 and five resistors R3-1, R3-2, . . . R3-5, as well as an input terminal and an output terminal; the emitter of the transistor Q3-1 is connected to one terminal of the resistor R3-1, the other terminal of the resistor R3-1 is connected to one electrode of the input terminal of the first driving circuit, the base of the transistor Q3-1 is respectively connected to one terminal of the resistors R3-2 and R3-3, the other terminal of the resistors R3-2 and R3-3 is respectively connected to the two electrodes of the input terminal of the first driving circuit, the collector of the transistor Q3-1 is connected to one terminal of the resistor R3-4, the other terminal of the resistor R3-4 is connected to one electrode of the output terminal of the first driving circuit, and the two terminals of the resistor R3-5 are respectively connected to the two electrodes of the output terminal of the first driving circuit.

5. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, wherein the second driving circuit comprises an optocoupler U4-1 and a resistor R4-1, as well as an input terminal and an output terminal; the anode of a light-emitting diode in the optocoupler U4-1 is connected to one terminal of the resistor R4-1, the other terminal of the resistor R4-1 is connected to one electrode of the input terminal of the second driving circuit, the cathode of the light emitting diode is connected to the other electrode of the input terminal of the second driving circuit, and the two terminals of a photosensitive tube in the optocoupler U4-1 are respectively connected to the two electrodes of the output terminal of the second driving circuit.

6. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, wherein the current detection and amplification circuit comprises a transistor Q5-1 and a resistor R5-1, as well as a detection input terminal and an output terminal; wherein the emitter and the base of the transistor Q5-1 are respectively connected to the two electrodes of the detection input terminal of the current detection and amplification circuit, the collector of the transistor Q5-1 is connected to one electrode of the output terminal of the current detection and amplification circuit, the other electrode of the output terminal is connected to a reference voltage point, and the two electrodes of the resistor R5-1 are respectively connected to the base and the emitter of the transistor Q5-1.

7. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, wherein the current detection and amplification circuit comprises an optocoupler U5-1 and an amplifier A5-1, as well as a detection input terminal and an output terminal; wherein the two terminals of a light-emitting diode in the optocoupler U5-1 are respectively connected to the two electrodes of the detection input terminal of the current detection and amplification circuit, the two terminals of a photosensitive tube in the optocoupler U5-1 are respectively connected to the two input terminals of the amplifier A5-1, and the two output terminals of the amplifier A5-1 are respectively connected to the two electrodes of the output terminal of the current detection and amplification circuit.

8. The wide-range positive-negative adjustable high-voltage DC power supply according to claim 7, wherein a proportional amplifier composed of an operational amplifier LM324 is used in the amplifier A5-1.

9. A method of controlling the wide-range positive-negative adjustable high-voltage DC power supply according to claim 1, comprising the following steps: step 1: producing positive and negative high voltages through the high-voltage generator, wherein the positive and negative high voltages are respectively sent to the positive high-voltage terminal and the negative high-voltage terminal, wherein the voltage value of the positive high-voltage terminal is greater than the upper limit value of the output voltage regulation range of the wide-range positive-negative adjustable high-voltage DC power supply, and the voltage value of the negative high-voltage terminal is less than the lower limit value thereof; step 2: inputting a PWM voltage regulation instruction by the instruction input terminal; step 3: converting the PWM voltage regulation instruction into an instruction voltage by the instruction voltage circuit; step 4: comparing and amplifying the instruction voltage with the feedback voltage from the voltage feedback circuit the error amplifier, and sending the operation results to the first driving circuit, and driving the first voltage regulating unit to adjust the voltage through the first driving circuit; step 5: detecting the emitter current of the PNP transistor Q1-1 in the first voltage regulating unit, and amplifying the detection results through the current detection and amplification circuit before sending them into the second driving circuit, and driving the second voltage regulating unit to participate in the voltage regulation through the second driving circuit; wherein the amplification factor of the current detection and amplification circuit should satisfy the following conditions: if the emitter current of the PNP transistor Q1-1 in the first voltage regulating unit is recorded as I.sub.1, which has a maximum value of I.sub.1M, then: when I.sub.10.1I.sub.1M, the NPN transistor Q2-1 in the second voltage regulating unit is driven to enter an off state; when 0<I.sub.1<0.1I.sub.1M, the NPN transistor Q2-1 in the second voltage regulating unit is driven to enter an amplification region to participate in the voltage regulation; and when I.sub.1=0, the emitter current of the NPN transistor Q2-1 in the second voltage regulating unit is driven to reach its maximum value; step 6: sampling and feeding back to the error amplifier the output voltage of the wide-range positive-negative adjustable high-voltage DC power supply by the voltage feedback circuit, comparing the output voltage with the instruction voltage, and controlling the output voltage to meet the instruction requirements after operation by the error amplifier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a structural schematic view of a wide-range positive-negative adjustable high-voltage DC power supply according to the present invention.

[0038] FIG. 2 is a circuit diagram of the first voltage regulating unit of the power supply shown in FIG. 1.

[0039] FIG. 3 is a circuit diagram of the second voltage regulating unit of the power supply shown in FIG. 1.

[0040] FIG. 4 is a circuit diagram of the first driving circuit of the power supply shown in FIG. 1.

[0041] FIG. 5 is a circuit diagram of the second driving circuit of the power supply shown in FIG. 1.

[0042] FIG. 6 is a circuit diagram of the current detection and amplification circuit of the power supply shown in FIG. 1.

[0043] FIG. 7 is a circuit diagram of the current detection and amplification circuit of the power supply shown in FIG. 1.

[0044] FIG. 8 is a structural schematic view of the wide-range positive-negative adjustable high-voltage DC power supply according to the present invention.

[0045] FIG. 9 is a structural schematic view of the wide-range positive-negative adjustable high-voltage DC power supply according to the present invention.

[0046] FIG. 10 is a structural schematic view of the wide-range positive-negative adjustable high-voltage DC power supply according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] The present invention will be further described below in detail with reference to examples and drawings; however, the embodiments of the present invention are not limited thereto.

Example 1

[0048] A wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 1, comprises the following components: a high-voltage generator 1, a negative high-voltage terminal 2, a positive high-voltage terminal 3, a first driving circuit 8, a first voltage regulating unit 7, a current detection and amplification circuit 6, a second driving circuit 5, a second voltage regulating unit 4 and an adjustable high-voltage output terminal 9; wherein the high-voltage generator 1 is respectively connected to the positive high-voltage terminal 3 and the negative high-voltage terminal 2, the positive high-voltage terminal 3 is connected to the input terminal of the first voltage regulating unit 7, the negative high-voltage terminal 2 is connected to the input terminal of the second voltage regulating unit 4, the output terminal of the first voltage regulating unit 7 is connected to the output terminal of the second voltage regulating unit 4 and then to the adjustable high-voltage output terminal 9, the output terminal of the first driving circuit 8 is connected to the driving terminal of the first voltage regulating unit 7, the current detection terminal of the first voltage regulating unit 7 is connected to the detection input terminal of the current detection and amplification circuit 6, the output terminal of the current detection and amplification circuit 6 is connected to the input terminal of the second driving circuit 5, and the output terminal of the second driving circuit 5 is connected to the driving terminal of the second voltage regulating unit 4.

[0049] In the wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 2, the first voltage regulating unit comprises m PNP transistors Q1-1, Q1-2, . . . Q1-m, with m being an integer greater than or equal to 1, m+1 resistors R1-0, R1-1, R1-2, . . . R1-m, and one Zener diode D1-1; collectors and emitters of the m PNP transistors are connected to each other in series in turn, wherein the emitter of the first transistor Q1-1 is connected to the anode of the Zener diode D1-1, the cathode of the Zener diode D1-1 is connected to one electrode of the current detection terminal of the first voltage regulating unit, the other electrode of the current detection terminal is connected to the input terminal of the first voltage regulating unit, one terminal of the resistor R1-0 is connected to one electrode of the driving terminal of the first voltage regulating unit, the other electrode of the driving terminal is connected to the input terminal of the first voltage regulating unit, the other terminal of the resistor R1-0 is connected to the base of the PNP transistor Q1-1, the two terminals of the resistor R1-m are respectively connected to the base and collector of the transistor Q1-m, the collector of the transistor Q1-m is also connected to the output terminal of the first voltage regulating unit, and the remaining m1 resistors are respectively connected across the bases of the m transistors connected in series in turn.

[0050] In the wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 3, the second voltage regulating unit comprises n NPN transistors Q2-1, Q2-2, . . . Q2-n, with n being an integer greater than or equal to 1, n+1 resistors R2-0, R2-1, R2-2, . . . R2-n, and one Zener diode D2-1; collectors and emitters of the n NPN transistors are connected to each other in series in turn, wherein the emitter of the first transistor Q2-1 is connected to the cathode of the Zener diode D2-1, the anode of the Zener diode D2-1 is connected to the input terminal of the second voltage regulating unit, one terminal of the resistor R2-0 is connected to one electrode of the driving terminal of the second voltage regulating unit, the other electrode of the driving terminal is connected to the input terminal of the second voltage regulating unit, the other terminal of the resistor R2-0 is connected to the base of the NPN transistor Q2-1, the two terminals of the resistor R2-n are respectively connected to the base and collector of the transistor Q2-n, the collector of the transistor Q2-n is also connected to the output terminal of the second voltage regulating unit, and the remaining n1 resistors are respectively connected across the bases of the n transistors connected in series in turn.

[0051] In the wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 4, the first driving circuit comprises one transistor Q3-1 and five resistors R3-1, R3-2, . . . R3-5; the emitter of the transistor Q3-1 is connected to one terminal of the resistor R3-1, the other terminal of the resistor R3-1 is connected to one electrode of the input terminal of the first driving circuit, the base of the transistor Q3-1 is respectively connected to one terminal of the resistors R3-2 and R3-3, the other terminal of the resistors R3-2 and R3-3 is respectively connected to the two electrodes of the input terminal of the first driving circuit, the collector of the transistor Q3-1 is connected to one terminal of the resistor R3-4, the other terminal of the resistor R3-4 is connected to one electrode of the output terminal of the first driving circuit, and the two terminals of the resistor R3-5 are respectively connected to the two electrodes of the output terminal of the first driving circuit.

[0052] In the wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 5, the second driving circuit comprises an optocoupler U4-1 and a resistor R4-1; the anode of a light-emitting diode in the optocoupler U4-1 is connected to one terminal of the resistor R4-1, the other terminal of the resistor R4-1 is connected to one electrode of the input terminal of the second driving circuit, the cathode of the light emitting diode is connected to the other electrode of the input terminal of the second driving circuit, and the two terminals of a photosensitive tube in the optocoupler U4-1 are respectively connected to the two electrodes of the output terminal of the second driving circuit.

[0053] In the wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 6, the current detection and amplification circuit comprises a transistor Q5-1 and a resistor R5-1; wherein the emitter and the base of the transistor Q5-1 are respectively connected to the two electrodes of the detection input terminal of the current detection and amplification circuit, the collector of the transistor is connected to one electrode of the output terminal of the current detection and amplification circuit, the other electrode of the output terminal is connected to a reference voltage point, and the two electrodes of the resistor R5-1 are respectively connected to the base and the emitter of the transistor Q5-1.

[0054] In the wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 7, the current detection and amplification circuit comprises an optocoupler U5-1 and an amplifier A5-1, the two terminals of a light-emitting diode in the optocoupler U5-1 are respectively connected to the two electrodes of the detection input terminal of the current detection and amplification circuit, the two terminals of a photosensitive tube in the optocoupler U5-1 are respectively connected to the two input terminals of the amplifier A5-1, and the two output terminals of the amplifier A5-1 are respectively connected to the two electrodes of the output terminal of the current detection and amplification circuit; the amplifier A5-1 may be constituted by a known technique, e.g., a proportional amplifier composed of an operational amplifier LM324 can be used.

[0055] The wide-range positive-negative adjustable high-voltage DC power supply, as shown in FIG. 1, also comprises an instruction input terminal 10, an instruction voltage circuit 11, an error amplifier 12 and a voltage feedback circuit 13; the instruction input terminal 10 is connected to the input terminal of the instruction voltage circuit 11, the output terminal of the instruction voltage circuit 11 is connected to one input terminal of the error amplifier 12, the other input terminal of the error amplifier 12 is connected to the output terminal of the voltage feedback circuit 13, the output terminal of the error amplifier 12 is connected to the input terminal of the first driving circuit 18, the input terminal of the voltage feedback circuit 13 is connected to the adjustable high-voltage output terminal 9; the high-voltage generator 1, the instruction voltage circuit 11, the error amplifier 12, and the voltage feedback circuit 13 are all constituted by a known technique, e.g., the high-voltage generator can include a high-frequency high-voltage oscillator composed of a high-voltage transformer and a transistor, so as to produce the high-frequency AC high-voltage power supply, and then a positive-negative DC high-voltage power supply is obtained by rectification with the high-frequency rectifier; the instruction voltage circuit may be composed of an RC low-pass filter and a resistor voltage-dividing circuit; a PI regulator composed of the operational amplifier LM324 can be used as the error amplifier; and a suitable resistor voltage-dividing circuit can be used as the voltage feedback circuit.

[0056] A method of controlling the wide-range positive-negative adjustable high-voltage DC power supply is provided, comprising the following steps:

[0057] Step 1: The high-voltage generator produces positive and negative high voltages, which are respectively sent to the positive high-voltage terminal and the negative high-voltage terminal, wherein the voltage value of the positive high-voltage terminal is greater than the upper limit value of the output voltage regulation range of the wide-range positive-negative adjustable high-voltage DC power supply, and the voltage value of the negative high-voltage terminal is less than the lower limit value thereof;

[0058] step 2: a PWM voltage regulation instruction is inputted by the instruction input terminal;

[0059] step 3: the PWM voltage regulation instruction is converted into an instruction voltage by the instruction voltage circuit;

[0060] step 4: the error amplifier compares the instruction voltage with the feedback voltage from the voltage feedback circuit and amplifies it, and sends the operation results to the first driving circuit, and the first driving circuit drives the first voltage regulating unit to adjust the voltage;

[0061] step 5: the current detection and amplification circuit detects the emitter current of the PNP transistor Q1-1 in the first voltage regulating unit, and amplifies the detection results before sending them into the second driving circuit, and the second driving circuit drives the second voltage regulating unit to participate in the voltage regulation;

[0062] wherein the amplification factor of the current detection and amplification circuit should satisfy the following conditions:

[0063] if the emitter current of the PNP transistor Q1-1 in the first voltage regulating unit is recorded as I1, which has a maximum value of I.sub.1M, then:

[0064] when I.sub.10.1I.sub.1M, the NPN transistor Q2-1 in the second voltage regulating unit is driven to enter an off state;

[0065] when 0<I.sub.10.1I.sub.1M, the NPN transistor Q2-1 in the second voltage regulating unit is driven to enter an amplification region to participate in the voltage regulation; and

[0066] when I.sub.1=0, the emitter current of the NPN transistor Q2-1 in the second voltage regulating unit is driven to reach its maximum value;

[0067] step 6: the output voltage of the wide-range positive-negative adjustable high-voltage DC power supply is sampled and fed back to the error amplifier by the voltage feedback circuit, compared with the instruction voltage, and is used to control the output voltage to meet the instruction requirements after operation by the error amplifier.

Example 2

[0068] As shown in FIG. 8, in this example, the first voltage regulating unit is composed of two transistors in series, the second voltage regulating unit is composed of three transistors in series, the current detection and amplification circuit adopts the first solution shown in FIG. 4, the instruction voltage circuit is composed of an RC low-pass filter and a resistor voltage-dividing circuit, a PI regulator composed of the operational amplifier LM324 is used as the error amplifier, and the voltage feedback circuit is composed of a resistor voltage-dividing circuit; besides, a Zener diode D0-1 is connected between the output terminals of the first voltage regulating unit and the second voltage regulating unit, so as to add a second high-voltage output terminal having a fixed voltage difference from the voltage value of the adjustable high-voltage output terminal to meet the needs of the application side; a resistor R2A-1 is added to the emitter circuit of the transistor Q2-1 in the second voltage regulating unit to improve the adjustment characteristics of the second voltage regulating unit; the remaining portions are the same as those in Example 1.

Example 3

[0069] As shown in FIG. 9, in this example, the first voltage regulating unit is composed of three transistors in series, the second voltage regulating unit is composed of four transistors in series, the current detection and amplification circuit adopts the second solution shown in FIG. 5, and the first driving circuit employs the same circuit as the second driving circuit shown in FIG. 3, so as to meet the higher positive high-voltage output requirements; the instruction voltage circuit, the error amplifier, and the voltage feedback circuit are the same as those in Example 2, and a resistor R2A-1 is also added to the emitter circuit of the transistor Q2-1 in the second voltage regulating unit; the remaining portions are the same as those in Example 1.

Example 4

[0070] As shown in FIG. 10, in this example, with a common high-voltage generator cooperating with a plurality of groups of the voltage regulating units, the multi-channel independent wide-range positive-negative adjustable DC high-voltage output can be obtained; the configuration of the respective voltage regulating units is the same as that in Example 1.

[0071] The above examples are preferred embodiments of the present invention; however, the embodiments of the present invention are not limited thereto, and any other modification, amendment, replacement, combination and simplification not departing from the spirit and principle of the present invention shall be the equivalent permutation, and all fall within the scope of protection of the present invention.