Patent ID: 8837180

Claim:
A power supply switch apparatus comprising: a voltage decreasing circuit receiving a first alternating voltage output from a power supply and converting the first alternating voltage to a second alternating voltage; a rectification circuit receiving the second alternating voltage and converting the second alternating voltage to a first direct voltage; a voltage regulating circuit receiving the first direct voltage and converting the first direct voltage to a second direct voltage; a comparison circuit receiving the second direct voltage and comparing the second direct voltage with a reference voltage and outputting a control signal; and a control circuit receiving the control signal and connecting the power supply to different circuits according to the control signal; wherein the voltage regulating circuit comprises at least a first resistor and a second resistor; and the connection point of the first resistor and the second resistor outputs the second direct voltage; the comparison circuit comprises a comparator and a variable resistor; the variable resistor comprises a first end, a second end, and an adjusting end; the first end receives a third direct voltage; the second end connects to ground; an in-phase input end of the comparator connects the connection point of the first resistor and the second resistor; an anti-phase input end of the comparator connects the adjusting end of the variable resistor and receives the reference voltage; and an output end of the comparator outputs the control signal.