Patent ID: 7646222

Claim:
A semiconductor device which generates a power ON reset signal, comprising: a reference voltage generating circuit which receives a first power supply voltage and generates a reference voltage whose value is smaller than that of the first power supply voltage; a reference voltage level guarantee circuit which is connected to the reference voltage generating circuit, and which senses that a value of the reference voltage has reached a first predetermined value and generates a first sense signal; a first power supply voltage sensing circuit which is connected to the reference voltage generating circuit and the reference voltage level guarantee circuit, and which includes a first voltage comparator circuit which compares a first voltage having a value that corresponds to the first power supply voltage with the reference voltage, an operation of the comparator circuit being controlled based on the first sense signal, the first power supply voltage sensing circuit outputting a second sense signal based on a comparison result of the first voltage comparator circuit; a second power supply voltage sensing circuit which is connected to the reference voltage generating circuit and the first power supply voltage sensing circuit, and which includes a second voltage comparator circuit which compares a second voltage with the reference voltage, the second voltage having a value that corresponds to a second power supply voltage which is different from the first power supply voltage, the second power supply voltage sensing circuit outputting a third sense signal based on a comparison result of the second voltage comparator circuit; and a power ON reset signal output circuit which is connected to the first and second power supply voltage sensing circuits, and which outputs a power ON reset signal based on the second sense signal and the third sense signal.