Patent ID: 8144485

Claim:
A direct current voltage conversion circuit comprising: a power supply; a first output; a second output; a transformer comprising a primary coil and a secondary coil; a first voltage-regulating circuit comprising: a transistor including a drain electrode and a source electrode; a first capacitor connected between ground and the first output; and a first diode, having an anode and a cathode, wherein the first output is capable of being 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; a second voltage-regulating circuit, wherein 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 second voltage-regulating circuit comprises a second diode, the primary coil of the transformer and the second diode is connected in series between the power supply and the second output; and a step-up DC-DC converter configured to receive a first feedback voltage from the first output and regulate a first voltage of the first output by turning on or turning off the transistor according to the first feedback voltage, and further configured to receive a second feedback voltage from the second output and regulate the second voltage of the second output according to the second feedback voltage.