Patent ID: 6972602

Claim:
A power-on reset circuit comprising: a power supply voltage detection circuit that detects a rise of a power supply voltage to a predetermined voltage and that causes a logic level of a first internal node to go from a first level to a second level; a capacitor charge/discharge circuit that discharges a capacitor when the logic level of the first internal node of the power supply voltage detection circuit is the first level and that charges the capacitor via a resistor when the logic level is the second level; and a reset pulse generation circuit that before the power supply voltage rises higher than the predetermined voltage, outputs a first output voltage to an output node and that after the power supply voltage has risen higher than the predetermined voltage, outputs a second output voltage to the output node upon detecting that a charge level of the capacitor has become higher than a charge level detection voltage, wherein in an event that the power supply voltage is reduced, the capacitor charge/discharge circuit discharges the capacitor to follow the event, regardless of the logic level of the first internal node.