Voltage regulator for alternator of vehicle

摘要

A voltage regulator for controlling electric power generated by an alternator coupled to a vehicle engine is disclosed. The regulator comprises a switching circuit for regulating an output voltage from the alternator or a voltage for charging the battery of the vehicle to a predetermined value by controlling a current flowing through the rotor coil of the alternator, a comparator for detecting ON-state of the switching circuit, a smoothing circuit for detecting the average ON duty of the switching circuit by smoothing the output of the comparator, and a reference-voltage generating circuit for generating and issuing a reference voltage in response to the average ON duty to the switching circuit. The voltage regulator detects the load condition of the alternator from the average ON duty of the switching circuit and regulates the output voltage of the alternator or the voltage for charging the battery of the vehicle in accordance with the load condition to charge the battery in proper condition.