Protection system for series regulator

• US 4,401,936 A
• Filed: 01/12/1981
• Issued: 08/30/1983
• Est. Priority Date: 01/12/1981
• Status: Expired due to Fees

• Current Assignee: Tympanium Corp. (Standard Motor Products Incorporated)
• Original Assignee: Tympanium Corp. (Standard Motor Products Incorporated)
• Inventors: van Opijnen, L. J. K.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US06/224,654
• Time in Patent Office: 960 Days
• Field of Search: 320/57, 320/59, 320/DIG. 2, 322/28, 322/89, 322/90, 322/94, 322/95, 323/276, 361/18
• US Class Current: 320/127
• CPC Class Codes: G05F 1/571 with overvoltage detector
• CPC Class Codes: H02J 7/1492 by means of controlling devices between the generator output and the battery
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles

Abstract

A protection system is described for series regulators exposed to power sources such as permanent magnet alternators which may exhibit high open circuit voltages. The subject system includes a circuit which protects the control transistor in the regulator from a forward bias second breakdown by clamping it OFF responsive to the alternator output voltage exceeding a predetermined level. In one embodiment the clamping circuit keeps this transistor off during enough of the duty cycle to reduce the voltage across the control transistor to a level above which second breakdown occurs. In one embodiment, an auxiliary circuit shorts the alternator output terminals to ground to protect electrical apparatus connected to the alternator from burn-out due to high voltages occasioned by sulfated batteries or loose battery terminals which result in a high impedance being presented to the alternator.

Claims

1. A regulator circuit adapted to be connected between the output terminals of a power source which provides an A.C. signal at its output terminals to the terminals of a battery comprising:

rectifying means interposed between the terminals of said power source and said battery, said rectifying means having switching elements adapted when opened to interrupt the circuit between the terminals of the power source and battery;

means including a control transistor for opening said switching elements responsive to a predetermined battery charge; and

means connected to the terminals of said power source and responsive to the output voltage of said power source relative to the battery voltage for clamping said control transistor off during enough of the AC duty cycle to reduce the energy through said control transistor to a level below which forward bias second breakdown occurs, said rectifying means including a diode bridge circuit having a first pair of opposite points connected across the terminals of said power source and a second pair of opposite points coupled across the terminals of said battery, said switching elements including silicon controlled rectifiers having control terminals coupled to a first electrode of said control transistor and to different ones of said first pair of points, a second electrode of said control transistor being connected to a first one of said battery terminals, said clamping means including means for clamping the control electrode of said control transistor to said first one of said battery terminals.

2. The circuit of claim 1 wherein said clamping means includes means for detecting a predetermined voltage differential between said power source terminals and the voltage at said first battery terminal and for actuating said clamping means when said predetermined differential has been exceeded.

3. The circuit of claim 2 wherein said detecting means includes a voltage dividing circuit and a rectifying circuit connected between said power source terminals and said first battery terminal.

4. The circuit of claim 3 wherein said voltage dividing circuit includes a Zener diode.

5. The circuit of claim 3 wherein said control electrode is coupled to a predetermined point in said voltage dividing circuit.

6. The circuit of claim 2 and further including means for shorting said power source terminals responsive to a high impedance being presented to the output of said rectifying means.

7. The circuit of claim 6 wherein said shorting means includes means for detecting when the voltage at said first battery terminals exceeds a predetermined level.

8. The circuit of claim 7 wherein said predetermined level is different from said predetermined battery charge.