A switch-mode power supply includes a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source, a pair of output terminals for supplying a direct current (DC) voltage output to a load, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. The power supply also includes a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, and a control circuit coupled to operate the at least four switches to supply the DC voltage output to the load.

A method for controlling a discharge of a power storage device includes: a first step of discharging, in a first section of a discharging period, a part of an electric charge stored in a power storage through a first discharge path and a second discharge path of a discharge circuit; and a second step of discharging, in a second section of the discharging period, a remaining part of the electric charge through the second discharge path. The first discharge path includes a zener diode connected to one end of the power storage. The second discharge path includes a first transistor connected to the one end of the power storage. The first section is a period in which a voltage of the one end of the power storage is higher than a breakdown voltage of the zener diode. The second section is a period in which a voltage of the one end of the power storage is lower than the breakdown voltage of the zener diode. An output current of the first transistor in the second section is greater than an output current of the first transistor in the first section.

A power supply device with low loss includes an input switch circuit, a transformer, a first capacitor, an output stage circuit, and a detection and control circuit. The input switch circuit generates a switching voltage according to an input voltage. The output stage circuit generates an output voltage. The output stage circuit includes a first rectifying switch element and a second rectifying switch element. The detection and control circuit detects a first output current flowing through the first rectifying switch element so as to generate a first control voltage, and it detects a second output current flowing through the second rectifying switch element so as to generate a second control voltage. The first rectifying switch element is selectively closed or opened according to the first control voltage. The second rectifying switch element is selectively closed or opened according to the second control voltage.

A switch-mode power supply includes a pair of input terminals, a pair of output terminals, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. First and second ones of the at least four switches define a first half-bridge and third and fourth ones of the at least four switches define a second half-bridge. The power supply also includes a fifth switch coupled across the second switch and the third switch to short circuit the second switch and the third switch when the fifth switch is closed, and a control circuit. The control circuit includes a voltage-controlled oscillator (VCO) and multiple logic gates and flip-flops coupled to operate the at least four switches with zero-voltage switching (ZVS).

A switch-mode power supply includes a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source, a pair of output terminals for supplying a direct current (DC) voltage output to a load, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. The power supply also includes a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, and a control circuit coupled to operate the at least four switches to supply the DC voltage output to the load.

A switch-mode power supply includes a pair of input terminals, a pair of output terminals, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. First and second ones of the at least four switches define a first half-bridge and third and fourth ones of the at least four switches define a second half-bridge. The power supply also includes a fifth switch coupled across the second switch and the third switch to short circuit the second switch and the third switch when the fifth switch is closed, and a control circuit. The control circuit includes a voltage-controlled oscillator (VCO) and multiple logic gates and flip-flops coupled to operate the at least four switches with zero-voltage switching (ZVS).

A switch-mode power supply includes a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source, a pair of output terminals for supplying a direct current (DC) voltage output to a load, and at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals. The power supply also includes a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, and a control circuit coupled to operate the at least four switches to supply the DC voltage output to the load.

A method for controlling a discharge of a power storage device includes: a first step of discharging, in a first section of a discharging period, a part of an electric charge stored in a power storage through a first discharge path and a second discharge path of a discharge circuit; and a second step of discharging, in a second section of the discharging period, a remaining part of the electric charge through the second discharge path. The first discharge path includes a zener diode connected to one end of the power storage. The second discharge path includes a first transistor connected to the one end of the power storage. The first section is a period in which a voltage of the one end of the power storage is higher than a breakdown voltage of the zener diode. The second section is a period in which a voltage of the one end of the power storage is lower than the breakdown voltage of the zener diode. An output current of the first transistor in the second section is greater than an output current of the first transistor in the first section.

In a described example, a circuit includes a mode control circuit having an input and a mode control output. The mode control output is adapted to be coupled to a mode input of a DC-to-DC power converter. The mode control circuit is configured to provide a mode control signal at the mode control output. The mode control signal has a frequency and a duty cycle for causing the power converter to operate within an inaudible frequency range by transitioning the power converter between a power save mode and a pulse width modulation (PWM) mode. The mode control circuit is configured to control the duty cycle responsive to the input of the mode control circuit.

A primary controller applied to a primary side of a power converter includes a current compensation circuit and a compensation voltage generation circuit. The current compensation circuit is used for generating a compensation current to a sensing resistor of the primary side according to a direct voltage and an auxiliary voltage, wherein the auxiliary voltage corresponds to an output voltage of a secondary side of the power converter, and the compensation current changes a peak voltage of the primary side. The compensation voltage generation circuit is used for generating a compensation voltage according to a reference current, a discharge time of the secondary side, and a peak current, wherein the reference current is changed with the output voltage. The compensation current and the reference current are used for making an output current of the secondary side of the power converter not be changed with the output voltage.