Patent ID: 8138807

Claim:
A power-on detecting circuit comprising: a level shifter that, when a high supply potential has risen, converts the ground potential into the high supply potential and outputs the high supply potential when a ground potential is input, and converts the high supply potential into the ground potential and outputs the ground potential when the high supply potential is input; an input circuit that inputs the high supply potential to the level shifter when a low supply potential has not risen, and that inputs the ground potential to the level shifter when the low supply potential has risen, wherein the input circuit includes a voltage dropping element that is connected between an input side of the level shifter and the high supply potential; a first latch circuit that is connected to the input side of the level shifter, that maintains output at the ground potential when the low supply potential is input, and that changes output to high impedance when the ground potential is input; and a first capacitor that applies the ground potential to an input side of the first latch circuit when the low supply potential has not risen, and the output circuit includes a second latch circuit that is connected to the output side of the level shifter, and that maintains input as it is to be output when the low supply potential has risen; and a second capacitor that applies the ground potential to an input side of the second latch circuit when the high supply potential has not risen; and an output circuit that is connected on an output side of the level shifter, and that outputs the ground potential when the high supply potential has not risen.