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U.S. Department of Energy
Office of Scientific and Technical Information

Protection circuit for voltage regulator of vehicle mounted generator

Patent ·
OSTI ID:6455682

This patent describes a charging generator system including an A.C. generator having an armature winding and a field winding, a battery to be charged by a rectified output of the A.C. generator and a voltage regulator for regulating the rectified output of the A.C. generator to a first predetermined value. The field winding is energized by the rectified output of the generator. A protection circuit is included for protecting the charging generator system against a short-circuit of the field winding. The protection circuit comprises: an output transistor connected in series with the field winding to on-off control a field current thereof; a resistor connected to a base of the output transistor; a drive transistor connected in series between the resistor and the base of the output transistor; a detection transistor for detecting a current flowing through the resistor; a comparator having hysterisis characteristics; a capacitor connected to an input of the comparator and adapted to be charged by a logical product of an output voltage of the detection transistor and a terminal voltage of the output transistor; and a resistor constituting a discharging circuit for the capacitor. The drive transistor is turned-off when the capacitor is charging.

Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo
Patent Number(s):
US 4658200
OSTI ID:
6455682
Country of Publication:
United States
Language:
English