Patent ID: 8868938

Claim:
A power circuit applicable to a data storage device, the power circuit comprising: a boost circuit to receive a first voltage from a motherboard and convert the first voltage to a second voltage; a control circuit comprising: a charging capacitor; a charging and discharging circuit to receive the second voltage and charge the charging capacitor, wherein the charging and discharging circuit comprises a charging chip, an inductor, first to fifth capacitors, and first to fifth resistors, an input pin of the charging chip is connected to a first end of the inductor, a second end of the inductor is connected to the boost circuit, the first capacitor is connected between the first end of the inductor and ground, the second capacitor is connected between the second end of the inductor and ground, the third capacitor is connected between first and second I/O pins of the charging chip, the first resistor is connected between a third I/O pin of the charging chip and ground, a fourth I/O pin of the charging chip is connected to the boost circuit and also grounded through the second resistor, the third and the fourth resistors are connected in parallel between a fifth I/O pin of the charging chip and ground, a sixth I/O pin of the charging chip is connected to a seventh I/O pin of the charging chip through the fifth resistor, and also connected to the charging capacitor, and the fourth and the fifth capacitors are connected in parallel between the seventh I/O pin and ground; a voltage detecting circuit to detect whether the second voltage exists or not, wherein the voltage detecting circuit outputs a first selection signal in response to the voltage detecting circuit detects that the second voltage exists, the voltage detecting circuit outputs a second selection signal, and also outputs a control signal to the charging and discharging circuit to control the charging capacitor to discharge in response to the voltage detecting circuit detects that the second voltage does not exist; and a voltage selection circuit to receive the first selection signal and output the second voltage according to the first selection signal, or receive the second selection signal and output a discharging voltage of the charging capacitor according to the second selection signal; and first and second buck circuits to receive the second voltage or the discharging voltage of the charging capacitor, and convert the second voltage or the discharging voltage to different voltages and provide the different voltages to a control chip of the data storage device.