Patent ID: 7129594

Claim:
A control system for a vehicular generator comprising: a generator that is installed on a vehicle and has an armature coil and a field coil; a battery that is installed on said vehicle so as to be charged by a power generation voltage output from said armature coil; and a control circuit that has a voltage detection circuit for detecting a terminal voltage of said battery, and adjusts said power generation voltage to a predetermined voltage by controlling to turn a field current supplied to said field coil on and off in accordance with the terminal voltage of said battery; wherein a single control terminal is provided on said control circuit; an external control unit is connected to said control terminal; said external control unit supplies either one of a ground signal, an open signal and a pull-up signal to said control terminal as a control signal in accordance with the terminal voltage of said battery and an operating condition of said vehicle; and said control circuit serves to make said generator into a power generation stop state by interrupting said field current in response to said ground signal supplied to said control terminal, adjust said power generation voltage to a first control voltage for normal time by controlling to turn said field current on and off in response to said open signal supplied to said control terminal, and adjust said power generation voltage to a second control voltage higher than said first control voltage by controlling to turn said field current on and off in response to said pull-up signal supplied to said control terminal.