Voltage regulator for controlling output of automotive alternator

• US 20030095025A1
• Filed: 10/04/2002
• Published: 05/22/2003
• Est. Priority Date: 11/08/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Maehara, Fuyuki
• Granted Patent: US 6,777,905 B2
• Time in Patent Office: Days
• US Class Current: 336/155
• CPC Class Codes: H02P 9/305 controlling voltage H02P9/302 takes precedence

Abstract

A voltage regulator controls an output of an automotive alternator by controlling an amount of excitation current supplied to a field winding of the alternator. The amount of the excitation current is sensed by a sensing resistor as a sensed voltage appearing across the sensing resistor. The sensed voltage is amplified by an amplifier to obtain a detected voltage, an amplifying factor of which is adjusted based on an reference voltage precisely corresponding to the amount of the excitation current, and thereby the detected voltage is equalized to the reference voltage. In this manner, the excitation current is precisely detected without mechanically adjusting a resistance of the sensing resistor by function-trimming or the like.

Claims

1. A voltage regulator for controlling an output of an automotive alternator by controlling an amount of excitation current supplied to a field winding of the alternator, the voltage regulator comprising:

means for detecting an amount of the excitation current supplied to the field winding as a detected voltage representing the amount of the excitation current; and

means for adjusting the detected voltage by comparing the detected voltage with a reference voltage, so that the detected voltage correctly represents the amount of the excitation current.

2. The voltage regulator as in claim 1, wherein:

the detecting means includes a sensing resistor, through which current proportional to the excitation current flows and across which a sensed voltage appears, and an amplifier for amplifying the sensed voltage thereby to obtain the detected voltage; and

the adjusting means adjusts an amplification factor of the amplifier to equalize the detected voltage to the reference voltage.

3. The voltage regulator as in claim 2, wherein:

the adjusting means includes a non-volatile memory; and

the amplification factor is adjusted according to a signal indicating a difference between the detected voltage and the reference voltage, the indicating signal being stored in the non-volatile memory.