Patent ID: 6476651
Filing Date: 2002-11-05
Classification: H03K

Abstract:
A power-off detection circuit comprising:a diode, which is electrically coupled between first and second power supply terminals, a first capacitor, which is electrically coupled between the diode and the second power supply terminal and is charged from the first power supply terminal via the diode, a first output transistor, which is electrically coupled between the first and second power supply terminals to output logic signals, a control transistor, which is electrically coupled between a first node connecting the diode to the first capacitor and the control terminal of the first output transistor, with its control terminal electrically coupled to the first power supply terminal, a voltage generating circuit, which is electrically coupled between a second node coupling the control transistor to the control terminal of the first output transistor and the second power supply terminal, wherein the voltage generating circuit comprises a second capacitor coupled in parallel to the first capacitor via the control transistor whereby current discharged from the first capacitor charges the second capacitor to change the state of the output transistor.