Power supply circuit for central processing unit

A power supply circuit applicable to a central processing unit (CPU) of a computer, the power supply circuit comprising:

• a pulse width modulation (PWM) controller comprising a first output terminal and a second output terminal;
• a first switch circuit connected to the PWM controller;
• a second switch circuit connected to the PWM controller;
• a control circuit comprising first to fifth resistors, a first capacitor, a diode, first electronic switch and second electronic switch, wherein an anode of the diode is connected to the second output terminal of the PWM controller, a cathode of the diode is connected to a first terminal of the first electronic switch through the first and the second resistors in series, a first end of the first capacitor is connected to a node between the first and the second resistors, a second end of the first capacitor is grounded, a first end of the third resistor is connected to a node between the second resistor and the first terminal of the first electronic, a second end of the third resistor is grounded, a second terminal of the first electronic switch is connected to a power source through the fourth resistor, a third terminal of the first electronic switch is ground, a first terminal of the second electronic switch is connected to the second terminal of the first electronic switch, a second terminal of the second electronic switch is connected to the power source through the fifth resistor, a third terminal of the second electronic switch is ground, the second terminal of the second electronic switch is connected to the first switch circuit to output first and third control signals, the second terminal of the first electronic switch is connected to the second switch circuit to output second and fourth control signals;
• a first compensation circuit connected to the first switch circuit and the PWM controller;
• a second compensation circuit connected to the second switch circuit and the PWM controller;
• a first power circuit connected to the first output terminal of the PWM controller and the CPU;
• and
• a second power circuit connected to the second output terminal of the PWM controller and the CPU;
• wherein when the computer is turned on, the first and second power circuits operate, the control circuit receives a pulse signal from the second output terminal of the PWM controller and output the first control signal to the first switch circuit, and the second control signal to the second switch circuit , the first switch circuit is turned on and the second switch circuit is turned off, the first compensation circuit outputs a first compensation signal to the PWM controller through the first switch circuit, the PWM controller regulates duty cycle of pulse signals and outputs the regulated pulse signals to the first and second power circuits according to the first compensation signal, to provide a stable voltage to the CPU;
• when the computer is in a standby mode, the first power circuit operates and the second power circuit does not operate, the control circuit does not receive a pulse signal from the PWM controller and outputs the third control signal to the first switch circuit, and the fourth control signal to the second switch circuit, the first switch circuit is turned off and the second switch circuit is turned on, the second compensation circuit outputs a second compensation signal to the PWM controller through the second switch circuit, the PWM controller regulates duty cycle of a pulse signal and outputs the regulated pulse signal to the first power circuit according to the second compensation signal, to provide a stable voltage to the CPU.