SOFTWARE CONTROLLED LATCHED VOLTAGE REGULATOR HAVING WIPER SWITCH DECODING

摘要

A software-controlled latched voltage regulator includes three bipolar transistors responsive to a wiper switch multiplexed signal to place a latch formed by the transistors in an energized state, thereby supplying power to a microcontroller. One of the bipolar transistors is responsive to a deenergization signal supplied by the microcontroller, under software control, to place the latch in a deenergized state wherein regulated power is no longer supplied to the microcontroller. The voltage regulator further includes a zener diode that provides a reference voltage for use in connection with one of the transistors to implement a decoding function that is applied to the switch multiplexed signal to provide a pair of wiper switch position signals for use by the microcontroller during operation. While the latch remains in an energized state, the supplied regulated voltage enables the microcontroller to park a wiper arm of a wiper system, even though an ignition switch is an off position. Once the wiper arm is parked, as sensed by cam switches, the microcontroller deactivates the latch by generating the deenergization signal to power down the system in order to reduce current draw.