ON-VEHICLE ELECTRONIC CONTROLLER

摘要

PROBLEM TO BE SOLVED: To increase start time accuracy and reduce power consumption in a long time start timer circuit for an on-vehicle electronic controller.

SOLUTION: This on-vehicle electronic controller 100a comprises a main control circuit part 110a powered from an on-vehicle battery 101 through an open/close element 104a and a main power circuit 114a and a start timer circuit part 120a always powered through an auxiliary power circuit 124. The timer circuit part 120a comprises a sub CPU 121a operating in synchronism with high-speed clock signals and a counter for clocking counting the subharmonic signals of low-speed clock signals. When a power switch 102 is opened and the open/close element 104a is cut off, the timer circuit part 120a periodically measures a target awake time by comparing the frequency of the low-speed clock signals with the frequency of the high-speed clock signals.

COPYRIGHT: (C)2006,JPO&NCIPI