Patent ID: 7464206

Claim:
A semiconductor device comprising: a power line to be externally supplied with a power supply voltage; a ground line for grounding; a first signal line for transmitting a first signal; a second signal line for transmitting a second signal; a first switching element and a first resistance element connected in series between said first signal line and a power terminal which supplies a predetermined potential; a second switching element and a second resistance element connected in series between said second signal line and said ground line; a controller which is connected to said power line, said ground line, said first signal line, and said second signal line, and, when detecting that a potential of said power line has reached the power supply voltage, turns on said first switching element and said second switching element, and turns off said second switching element after an elapse of a predetermined time; and a second comparator having a first input terminal connected to said power terminal, a second input terminal connected to said first signal line via a third switching element, and an output terminal connected to said controller, wherein said controller turns on said first switching element, said second switching element, and said third switching element, when detecting that the potential of said power line has reached the power supply voltage, said second comparator compares a potential of said power terminal with a potential of said first signal line, and outputs a comparison result to said controller, and said controller turns off said second switching element and said third switching element, when detecting that the comparison result output from said second comparator has changed.