Voltage regulator of vehicle AC generator having variable bypass circuit resistance

A voltage regulator of a vehicle AC generator including a field circuit having a field coil and a plurality of magnetic poles and an output circuit having an armature coil, said voltage regulator comprising:

• a control circuit for supplying field current to said field coil;
• a power circuit for supplying electric power to said control circuit to operate the same;
• first means, including input terminal and a detection line connecting said input terminal to said armature coil, for detecting a self-excited voltage generated in said armature coil;
• a power drive circuit for controlling said power circuit according to a self-excited voltage induced in said armature coil, said power drive circuit including a pulse conversion circuit for converting said self-excited voltage into a binary pulse signal;
• a bypass circuit having a variable resistance, connected between said input terminal and a ground, for bypassing leak current flowing in said armature to the ground;
• and
• second means for decreasing said variable resistance of said bypass circuit when said self-excited voltage is not detected and increasing said variable resistance of said bypass circuit when said self-excited voltage is detected.

A voltage regulator of a vehicle AC generator for charging a battery, said AC generator including a field circuit having a field coil and a plurality of magnetic poles, an output circuit having a plurality of phase-windings and a rectifier unit for providing DC output power, said voltage regulator comprising:

• means, including and input terminal and a detection line connecting said input terminal to a portion of said phase windings, for detecting a self-excited voltage that is induced in said phase-windings by a residual magnetic field;
• a switching circuit for controlling field current to be supplied to said field coil;
• a switch control circuit for controlling said switching circuit;
• a power circuit connected to said switch control circuit;
• and
• a power-drive circuit including a pulse conversion circuit for converting said self-excited voltage into a binary pulse signal, said power-drive circuit driving said power circuit for a predetermined period from an edge of said binary pulse signal, wherein said pulse conversion circuit comprises a comparator connected to one of said phase-windings and a flip flop circuit connected to said comparator.