INTEGRATED CIRCUIT FOR DETECTING POWER FAILURE AND ITS RECOVERY

摘要

PURPOSE:To attain an interlock function between a microcomputer power supply and another power supply, by using a reset signal. CONSTITUTION:A commercial power supply VinA is transmitted through a rectifying/smoothing part 7, and the output of the part 7 is compared with a microcomputer power supply VCC at a comparing part 1. A control part 2 applies a control signal properly to a delay introduction counter part 3 in response to the output given from the part 1. The part 3 counts the clock pulses given from a clock pulse oscillating part 4 under the control of the part 2 and supplies selectively the output of pulse counting to an output part 6. The part 6 receives the signal from the part 3 and delivers a reset signal and a power failure detecting signal PDOWN as output signals. The reset signal has a rise after the VCC is fixed and then a fall before interruption of the VCC. Therefore an interlock is possible between the VCC and another power supply by supplying the reset signal to another power supply switch 11.