Abstract: A power converter includes a PFC circuit, a first capacitor, a second capacitor and an auxiliary circuit. The PFC circuit provides a first intermediate voltage to the first capacitor. The auxiliary circuit includes a first auxiliary branch circuit and a second auxiliary branch circuit. When the first auxiliary branch circuit is enabled, and the first intermediate voltage is transmitted to the second capacitor through the first auxiliary branch circuit. When the second auxiliary branch circuit is enabled, the first intermediate voltage is boosted by the second auxiliary branch circuit, so that a second intermediate voltage is provided by the second capacitor. While an operation state of the load is switched between a light load condition and a heavy load condition, one of the first auxiliary branch circuit and the second auxiliary branch circuit is selectively enabled.

Abstract: A power converter includes a PFC circuit, a first capacitor, a second capacitor and an auxiliary circuit. The PFC circuit provides a first intermediate voltage to the first capacitor. The auxiliary circuit includes a first auxiliary branch circuit and a second auxiliary branch circuit. When the first auxiliary branch circuit is enabled, and the first intermediate voltage is transmitted to the second capacitor through the first auxiliary branch circuit. When the second auxiliary branch circuit is enabled, the first intermediate voltage is boosted by the second auxiliary branch circuit, so that a second intermediate voltage is provided by the second capacitor. While an operation state of the load is switched between a light load condition and a heavy load condition, one of the first auxiliary branch circuit and the second auxiliary branch circuit is selectively enabled.

Abstract: A method for phase compensating a power factor correction circuit is provided. Firstly, a present current value of an input current is sampled, and the sampled signal is filtered. Then, a present waveform of the input current corresponding to the present current value of the filtered sampled signal and a previous waveform of the input current corresponding to a previous current value of the filtered sampled signal are predicted, and a current error signal is generated according to a difference between the present waveform and the previous waveform. Then, the current error signal is adjusted, and an adjusted signal is generated. Then, a feedforward signal is added to the adjusted signal, and a phase compensation signal. Then, a current control signal is added to the phase compensation signal, and a pulse width modulation signal is generated to control a switching circuit.

Abstract: A method for phase compensating a power factor correction circuit is provided. Firstly, a present current value of an input current is sampled, and the sampled signal is filtered. Then, a present waveform of the input current corresponding to the present current value of the filtered sampled signal and a previous waveform of the input current corresponding to a previous current value of the filtered sampled signal are predicted, and a current error signal is generated according to a difference between the present waveform and the previous waveform. Then, the current error signal is adjusted, and an adjusted signal is generated. Then, a feedforward signal is added to the adjusted signal, and a phase compensation signal. Then, a current control signal is added to the phase compensation signal, and a pulse width modulation signal is generated to control a switching circuit.

Abstract: A compensating method for a ripple compensation circuit of a power supply is provided. The power supply includes an LLC resonant converter. The LLC resonant converter receives an input voltage and generates an output voltage. Firstly, the output voltage is subtracted from a reference voltage, so that a first error signal is generated. Then, a digital filter is provided to increase a low frequency gain of the first error signal, so that a second error signal is generated. Then, the first error signal and the second signal are added, so that a modulated error signal is generated. Then, a compensation signal is generated to control the LLC resonant converter according to the modulated error signal. Consequently, a low frequency gain of the input voltage is increased and a low frequency ripple of the output voltage is suppressed by an increased voltage loop compensator response.

Abstract: A compensating method for a ripple compensation circuit of a power supply is provided. The power supply includes an LLC resonant converter. The LLC resonant converter receives an input voltage and generates an output voltage. Firstly, the output voltage is subtracted from a reference voltage, so that a first error signal is generated. Then, a digital filter is provided to increase a low frequency gain of the first error signal, so that a second error signal is generated. Then, the first error signal and the second signal are added, so that a modulated error signal is generated. Then, a compensation signal is generated to control the LLC resonant converter according to the modulated error signal. Consequently, a low frequency gain of the input voltage is increased and a low frequency ripple of the output voltage is suppressed by an increased voltage loop compensator response.