Abstract: The present disclosure relates to a floating type boost-buck power factor correction (PFC) circuit and a light-emitting diode (LED) drive power supply. The floating type boost-buck PFC circuit includes a filter circuit, a rectifier bridge, a PFC control chip and a voltage sampling circuit, and further includes a PFC circuit; the PFC circuit includes a switching transistor Q1 and switching transistor Q2 with a withstand voltage of 600 V to 650 V, an energy storage inductor T1, a freewheel diode D0, a freewheel diode D1, an electrolytic capacitor E1 with a withstand voltage of 400 V to 450 V, a resistor RO and a capacitor C1. The LED drive power supply includes a DC/DC conversion circuit, an LLC control chip, an LED voltage/current sampling circuit, and the above floating type boost-buck PFC circuit.

Abstract: The present disclosure relates to an LLC resonant topology control circuit base on a flyback chip, including an LLC resonant cavity, a current mode flyback chip U1, a first drive circuit, a second drive circuit, a charge pump circuit and a feedback circuit, wherein the LLC resonant cavity includes a switching transistor Q1, a switching transistor Q2, a resonant inductor L1, a resonant capacitor C1 and an output transformer T1; the switching transistor Q1 is connected in series with the switching transistor Q2; the resonant inductor L1, a primary coil of the output transformer T1 and the resonant capacitor C1 are connected in series and then are connected in parallel to the switching transistor Q2; a gate of the switching transistor Q1 is connected with an output end of the first drive circuit, and an input end of the first drive circuit is connected with a GD end of current mode flyback chip U1; a gate of the switching transistor Q2 is connected with an output end of the second drive circuit, and an input end

Abstract: The present disclosure relates to a floating type boost-buck power factor correction (PFC) circuit and a light-emitting diode (LED) drive power supply. The floating type boost-buck PFC circuit includes a filter circuit, a rectifier bridge, a PFC control chip and a voltage sampling circuit, and further includes a PFC circuit; the PFC circuit includes a switching transistor Q1 and switching transistor Q2 with a withstand voltage of 600 V to 650 V, an energy storage inductor T1, a freewheel diode D0, a freewheel diode D1, an electrolytic capacitor E1 with a withstand voltage of 400 V to 450 V, a resistor RO and a capacitor C1. The LED drive power supply includes a DC/DC conversion circuit, an LLC control chip, an LED voltage/current sampling circuit, and the above floating type boost-buck PFC circuit.