Patent ID: 7439781

Claim:
A power detection circuit comprising: a first comparator block comparing a supply voltage with a first threshold value; a first capacitor having first and second terminals; a charge controller block controlling the charging of said first capacitor according to an output signal of said first comparator block; a second comparator block comparing a voltage in said first capacitor with a second threshold value so as to produce a power detection signal; and a second capacitor having first and second terminals, wherein said charge controller block includes a charging first-conductivity type MOS transistor having a first terminal thereof connected onto a first-potential power line, a second terminal thereof connected to the first terminal of said first capacitor, and a control terminal thereof receiving a first output signal transferred from said first comparator block; the second terminal of said first capacitor is connected to a second-potential power line; and the first terminal of said second capacitor is connected to the control terminal of said charging first-conductivity type MOS transistor, and the second terminal of said second capacitor is connected to the second terminal of said charging first-conductivity type MOS transistor.