Abstract: A power factor correction (PFC) circuit with a resonant snubber. The power factor correction (PFC) circuit has an input part (601) for receiving an AC voltage and outputting a first DC voltage; a main part (604) for converting the first DC voltage to a second DC voltage; and a snubber (500) for ensuring the main part operates in soft turn-on and soft turn-off. The main part (604) has a primary inductor and a primary diode connected in series, and a switch (606) connected to the connection node of the primary inductor and the primary diode. The snubber (500) has a cascaded device (a first diode and a resonant inductor connected in series) and a second diode connected in series, and a resonant capacitor connected between the connection node of the cascaded device and second diode, and the switch (606).

Abstract: A power factor correction (PFC) circuit with a snubber (500). The snubber of the PFC circuit uses a resonant capacitor (503) in conjunction with a resonant inductor (and two diodes) to make the voltage across the switch (606) increases slowly when the switch becomes turn-off from a turn-on state so as to reducing the switch loss. The snubber (500) of the PFC circuit at least comprises: a cascaded device which at least is composed of a first diode (501) and a resonant inductor (502), a second diode (504) connected in series with the cascaded device, and a resonant capacitor (503) connected to the anode of the second diode (504).

Abstract: A cell voltage balancer for balancing the voltage of the first cell and the voltage of the second cell. The cell voltage balancer includes the first input terminal, the second input terminal and the third input terminal. The cell voltage balancer includes a transformer, the first switch and the second switch. The transformer includes a primary winding and a secondary winding. The first switch and the primary winding are serially connected between the first input terminal and the second input terminal. The second switch and the secondary winding are serially connected between the second input terminal and the third input terminal. The first switch and the second switch are switched on and off alternatively. While the first switch is on and the second switch is off, the primary winding stores energy of the first cell in the transformer. On the contrary, the secondary winding recovers energy stored in the transformer into the second cell.