Stepping motor control device for automobile air-conditioning system

摘要

A stepping motor control device for an automobile air-conditioning system has a key-off home-position setting unit of a stepping motor for driving an air-conditioning door in response to switching of a key switch of the automobile off. The key-off home-position setting unit, responsive to switch of the key switch off, drives the stepping motor so that the air-conditioning door comes to a full-close position or a full-open position, stores data indicative of the full-close or full-open positions, as a current position of the air-conditioning door in a memory, and thereby finishes a home-position setting of the stepping motor. The key-off home-position setting unit is supplied with power from a power source under control of a timer for a prescribed time within which a home-position setting can be finished. When the key switch is turned on, the key-on control unit judges whether or not a current position of the air-conditioning door given by the key-off home-position setting unit is stored in the memory, and starts a normal air-conditioning control without performing a home-position setting if the current position is stored.