A high-compatibility dimmer circuit is provided, which includes an impedance inspection avoidance module, a dimming module and an alternating-current input module. The impedance inspection avoidance module is connected to a load via an output end. The dimming module is connected to the impedance inspection avoidance module and includes a control unit. The alternating-current input module is connected to the dimming module, and converts an input alternating voltage into a pulsating direct voltage so as to power the load and the dimming module. When the load is driven, the control unit starts timing and switches the impedance inspection avoidance module after a predetermined time period. In this way, the dimming module can directly power the load and perform dimming for the load according to a dimming signal.

A power conversion apparatus includes: a reactor; a rectifier circuit that includes a first leg including switching elements connected in series and a second leg connected in parallel with the first leg, including switching elements connected in series; and a smoothing capacitor that smooths an output voltage of the rectifier circuit. The power conversion apparatus also includes an inverter that converts a direct-current voltage smoothed by the smoothing capacitor into a drive voltage for a motor and applies the drive voltage to the motor; a voltage detection unit that detects the direct-current voltage; and a control unit that controls operation of the rectifier circuit and the inverter. The control unit controls operations of the switching elements on the basis of an induced voltage induced in the motor and a detected value of the direct-current voltage.

A bridgeless PFC circuit includes: a control module that collects a current flowing through a current sampling element; and when the current flowing through the current sampling element is greater than a first threshold, the control module controls a switch element to be turned on. Based on the current flowing through the current sampling element, the switch element can be controlled to be turned on, thereby implementing zero-voltage turn-on of the switch element. Because the collected current does not change abruptly, a delay requirement on a sampling control circuit included in the control module is lowered, and a signal anti-interference capability of the control module is strong.

Stable switching is disclosed for a power factor correction boost converter using an input voltage and an output voltage. In one example, a boost converter control system includes a gate driver coupled to a switch of a boost converter to generate a drive signal to control switching of the switch, wherein a period of the drive signal is adjusted using a current adjustment signal. A current control loop is coupled to the gate driver to receive a sensed input current from the boost converter and a desired input current and to generate the current adjustment signal to the gate driver. A current limiter is coupled to the gate driver and the current control loop to determine a duty cycle of the switch, to determine a maximum input current in response to the duty cycle, and to restrict the desired input current to below the maximum input current.

An integrated circuit for a power supply circuit, including: a first command value output circuit outputting a first command value to turn on a transistor of the power supply circuit for a first time period; an on signal output circuit outputting an on signal to turn on the transistor; a delay circuit delaying the on signal by a predetermined time period; a correction circuit correcting the first command value, to output a second command value to turn on the transistor for a second time period; and a driver circuit turning on and off the transistor based respectively on the delayed on-signal and the second command value. The correction circuit corrects the first command value based on the predetermined time period and a ratio between the second time period and another time period from when the transistor is turned off to when an inductor current of the power supply circuit reaches a predetermined value.

An induction heating apparatus according to an embodiment of the present specification comprises a main control circuit for adjusting the capacitance of the variable capacitor circuit according to a driving mode of the inverter circuit determined on the basis of a load resistance value of a container placed on the working coil and adjusting the magnitude of the direct current link voltage according to a final voltage value calculated on the basis of an equivalent resistance value of the container and the working coil and a required power value for the working coil.

A power conversion apparatus includes a converter circuit converting AC voltage output from an AC power supply into DC voltage. The converter circuit includes unit converters. The power conversion apparatus includes a low current-oriented controller the unit converters to cause current corresponding to a single phase to flow through a current detector, and a high current-oriented controller controlling operation of the unit converters based on a result of comparison between a duty command and a carrier signal, where the duty command is generated based on detection values detected by the current detector and a voltage detector. When the detection value detected by the current detector is less than or equal to a first threshold, the low current-oriented controller is activated, and when the detection value detected by the current detector is greater than the first threshold, the high current-oriented controller is activated.

The subject invention reveals new methods and structures for achieving single stage power conversion with both regulated input current and regulated output voltage processing a minimum of load power and thereby achieving higher efficiency than other singles stage power converters with both regulated input current and regulated output voltage and two stage power factor corrected power converters. The subject invention reveals power factor corrected converters that improve the efficiency of the single stage power factor corrected converters on which they are based by adding an auxiliary converter that processes a small fraction of the total load power.

During a light load (or no-load) operation of a totem pole power factor correction circuit (i.e., PFC), a pulse width modulation (PWM) controller can operate in a skip mode. Further, the PWM controller may disable portions of the PFC to reduce standby power consumption. In this mode, and in this disabled configuration, the output of the PFC may be peak charged over time to a voltage that could be damaging or destructive. This peak charging results from the PFC circuit's inability to fully charge/discharge EMI capacitors between half cycles of the input line voltage. The present disclosure provides circuits and methods to fully charge/discharge the EMI capacitors to prevent peak charging the output.

A method for operating a power converter and a control circuit are disclosed. The method includes, in a power converter including an input, a converter stage, a first switch connected between the input and the converter stage, a second switch connected between input nodes of the converter stage, and an output capacitor connected between output nodes of the converter stage: detecting an operating state of the power converter; and operating the power converter in a first operating mode when the power converter is in a first operating state. Operating the power converter in the first operating mode includes regulating an input current received at the input by a switched-mode operation of the first and second electronic switches.