Abstract: A switching power supply, a power adapter and a charger are provided. The switching power supply comprises a current-mode PWM control unit, a transformer, and a DC power supply circuit connected in series to a power compensation auxiliary circuit. The current-mode PWM control unit comprises a current detection terminal. An input of the DC power supply circuit is connected to an auxiliary voltage output. The auxiliary voltage output outputs an auxiliary voltage related to output voltage of the switching power supply. The power compensation auxiliary circuit is used to compare the output voltage and a threshold voltage. When the current output voltage of the switching power supply is not greater than the threshold voltage, the power compensation auxiliary circuit generates a DC voltage, thus providing a compensation voltage to the current detection terminal, otherwise no compensation voltage is provided.

Abstract: A resonant converter includes an input terminal, an output terminal, a first switch, a second switch, a third switch, a fourth switch, a frequency controller, a resonant capacitor, a first transformer, a second transformer, a feedback circuit and a synchronous rectification controller. The input terminal is connected to an external power supply and the output terminal is connected to an external load. The synchronous rectifier controller is used to output a fourth control signal for controlling the fourth switch based on a voltage at the first terminal of the secondary side of the first transformer, and output a third control signal for controlling the third switch based on a voltage at the second terminal of the secondary side of said second transformer. The present application can effectively reduce the switching losses of the primary side, allowing the resonant converter to operate at a variable high frequency.

Abstract: A drive transformer isolated-adaptive drive-circuit includes a power supply, a first MOSFET and a second MOSFET, the drain electrode of the first MOSFET coupled with the positive electrode of the power supply, and the source electrode of the first MOSFET coupled with the drain electrode of second MOSFET; the source of the second MOSFET coupled with the negative electrode of the power supply; a drive transformer having a first winding and a second winding; a first fast drive circuit, one end coupled with the first winding, the other end coupled with the first MOSFET; a second fast drive circuit, one end coupled with the second winding, the other end coupled with the second MOSFET; a first adaptive-dead-time control sub-circuit; and a second adaptive-dead-time control sub-circuit.

Abstract: A self-adaptive surge-proof circuit is used in a switching power supply device. The switching power supply device includes an AC input, a filter-rectifier circuit connected to the AC input, and a power converter circuit connected to the filter-rectifier circuit. The self-adaptive surge-proof circuit includes a surge suppression unit connected between the filter-rectifier circuit and the power converter circuit, a switching unit connected in parallel with the surge suppression unit for adjusting an input impedance of the switching power supply device, a sampling unit connected to the filter-rectifier circuit for collecting a surge signal from the filter-rectifier circuit, and a drive-controlling circuit connected to the sampling unit for generating a driving signal for controlling on and off of the switching unit according to the surge signal.

Abstract: A drive transformer isolated-adaptive drive-circuit includes a power supply, a first MOSFET and a second MOSFET, the drain electrode of the first MOSFET coupled with the positive electrode of the power supply, and the source electrode of the first MOSFET coupled with the drain electrode of second MOSFET; the source of the second MOSFET coupled with the negative electrode of the power supply; a drive transformer having a first winding and a second winding; a first fast drive circuit, one end coupled with the first winding, the other end is coupled with the first MOSFET; a second fast drive circuit, one end coupled with the second winding, the other end coupled with the second MOSFET; a first adaptive-dead-time control sub-circuit; and a second adaptive-dead-time control sub-circuit.