Abstract: A DC voltage conversion circuit (20) of the present disclosure includes a power supply (21), a first output (27), a second output (26), a transformer (22), a first voltage-regulating circuit (25), a second voltage regulating circuit (24), and a step-up DC-DC converter (23). The first voltage-regulating circuit includes a transistor (254) having drain and source electrodes, a first capacitor (252) connected between ground and the first output, and a first diode (251). The first output is connected to ground via the anode and cathode of the first diode, the transformer, and the drain and source electrodes of the transistor in series. The power supply is configured to provide a second voltage to the second output via the transformer and the second voltage-regulating circuit in series. The step-up DC-DC converter is configured to regulate voltages of the first and second outputs according to feedback voltages from the first and second outputs.

Abstract: An exemplary power supply circuit (20) includes a scaler (21), a field-effect transistor (23), a pulse width modulation circuit (25), and a capacitor (29). The scaler includes an output port (213). The pulse width modulation circuit includes an input port (251). The input port of the pulse width modulation circuit is grounded via the capacitor. The field-effect transistor includes a gate electrode (231), a source electrode (232), and a drain electrode (233). The gate electrode is connected to the output port of the scaler. The source electrode is grounded. The drain electrode is connected to the input port of the pulse width modulation circuit.

Abstract: A DC voltage conversion circuit (20) of the present disclosure includes a power supply (21), a first output (27), a second output (26), a transformer (22), a first voltage-regulating circuit (25), a second voltage regulating circuit (24), and a step-up DC-DC converter (23). The first voltage-regulating circuit includes a transistor (254) having drain and source electrodes, a first capacitor (252) connected between ground and the first output, and a first diode (251). The first output is connected to ground via the anode and cathode of the first diode, the transformer, and the drain and source electrodes of the transistor in series. The power supply is configured to provide a second voltage to the second output via the transformer and the second voltage-regulating circuit in series. The step-up DC-DC converter is configured to regulate voltages of the first and second outputs according to feedback voltages from the first and second outputs.

Abstract: An exemplary power supply circuit (20) includes a scaler (21), a field-effect transistor (23), a pulse width modulation circuit (25), and a capacitor (29). The scaler includes an output port (213). The pulse width modulation circuit includes an input port (251). The input port of the pulse width modulation circuit is grounded via the capacitor. The field-effect transistor includes a gate electrode (231), a source electrode (232), and a drain electrode (233). The gate electrode is connected to the output port of the scaler. The source electrode is grounded. The drain electrode is connected to the input port of the pulse width modulation circuit.