Patent ID: 8228079

Claim:
A voltage detecting circuit, for detecting a voltage state of a voltage source, comprising: a first route, between the voltage source and a ground voltage, comprising a first current source and a first MOS resistor, and connected in series at a first node for outputting a first voltage; a second route, between the voltage source and the ground voltage, comprising a second current source and a second MOS resistor, and connected in series at a second node for outputting a second voltage; and a comparator, for receiving the first voltage and the second voltage and outputting the voltage state, comprising: an offset circuit, for producing an offset voltage to the second voltage; and a voltage comparing unit, for comparing the first voltage and the second voltage with offset, and outputting the voltage state according to variance of a voltage difference, wherein the first route and the second route are identical in a circuit structure and device structures of the circuit structure, in that the first current source and the second current source are a same current source.