Power supply system

A power supply system comprising:

• a power supply unit configured to provide a working voltage for a motherboard via a first resistor;
• a voltage converting unit comprising a voltage converting chip configured to detect a first direct current (DC) voltage on the first resistor, and convert the first DC voltage to a second DC voltage;
• a comparison unit configured to receive the second DC voltage, compare the second DC voltage with the working voltage, and output a switch signal;
• wherein the comparison unit comprises a first switch;
• and
• a switching unit configured to receive the switch signal, and output a control signal to a central processing unit (CPU) on the motherboard according to the switch signal, wherein the switching unit comprises a second switch;
• when the working voltage output from the power supply unit to the motherboard is over voltage, the second DC voltage is greater than a reference voltage, the comparison unit outputs the switch signal at a high voltage level, the first switch and the second switch receive the switch signal at the high voltage level, the first switch and the second switch turn on, the second switch output the control signal at a low voltage level to the CPU, and the CPU decreases its working frequency according to the control signal at the low voltage level;
• and when the working voltage output from the power supply unit to the motherboard is normal, the second DC voltage is less than the reference voltage, the comparison unit outputs the switch signal at a low voltage level, the first switch and the second switch receive the switch signal at the low voltage level, the first switch and the second switch turn off, the second switch output the control signal at a high voltage level to the CPU, and the CPU remains its working frequency according to the control signal at the high voltage level;
• wherein the comparison unit further comprises a comparator;
• the comparator comprises a non-inverting input terminal, an inverting input terminal, and an output terminal;
• the first switch comprises a first terminal, a second terminal, and a third terminal;
• the non-inverting input terminal of the comparator is electrically coupled to the voltage output terminal of the voltage converting chip via a second resistor;
• the inverting input terminal of the comparator is configured to receive a third DC voltage via a third resistor;
• the output terminal of the comparator is configured to receive a fourth DC voltage via a sixth resistor;
• the output terminal of the comparator is electrically coupled to the first terminal of the first switch;
• the second terminal of the first switch is grounded;
• and the third terminal of the first switch is electrically coupled to the inverting input terminal of the comparator via a seventh resistor.