Battery charging system

• US 6,943,530 B2
• Filed: 03/26/2004
• Issued: 09/13/2005
• Est. Priority Date: 12/16/2001
• Status: Expired due to Fees

• Current Assignee: Zpower, Inc. (ZPower, LLC)
• Original Assignee: ZINC Matrix Power Incorporated
• Inventors: Cheiky, Michael, Yang, Te-Chien F.
• Primary Examiner(s): Sparks, Donald
• Assistant Examiner(s): LUK, LAWRENCE W
• Application Number:
  US10/810,205
• Publication Number:
  US 20040178772A1
• Time in Patent Office: 536 Days
• Field of Search: 320/162, 320/137, 320/141, 320/142, 320/143, 320/144, 320/145, 320/160, 320/163, 320/164, 323/266, 323/268, 323/299
• US Class Current: 320/162
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits

Abstract

A battery charging system comprising: a current source; a battery; and a voltage and current regulator, which regulates voltage applied to the battery and current supplied to the battery. The battery charging system shapes the current supplied to the battery, and may be used to taper the current supplied to the battery. The voltage and current regulator may comprise: an adjustable band-gap voltage reference diode, a potentiometer, a resistor, and a transistor, or an adjustable shunt regulator, and a transistor operating in conjunction with the adjustable shunt regulator, or other suitable voltage and current regulator means. The battery charging system regulates the current flow supplied to the battery, which originates from a constant charging current source. As the battery voltage exceeds a predefined terminal voltage, the battery charging system diverts charging current through a transistor, thus clamping the battery at the terminal voltage and shaping the current supplied to the battery.

Claims

1. A battery charging system, comprising:

a current source;

a plurality of batteries connected in series;

said current source in series with said batteries;

a plurality of voltage and current regulators, each said voltage and current regulator connected across a respective one of said batteries, each said voltage and current regulator regulating voltage applied to said respective battery and current supplied to said respective battery, each of said voltage and current regulators also being connected in series and comprising an adjustable band-gap voltage reference diode in series with a resistor, said series resistor and said band-gap voltage reference diode connected across said respective battery, said adjustable band-gap voltage reference diode having a reference input;

a voltage divider potentiometer connected across said respective battery, said voltage divider potentiometer having an output connected to said reference input of said adjustable band-gap voltage reference diode, and providing a reference input voltage at said reference input to said band-gap voltage reference diode; and

a transistor having an emitter and a collector connected across said respective battery, said transistor having a base connected to a junction between said series connected resistor and said band-gap voltage reference diode, said band-gap reference diode, said series resistor, and said transistor operating in conjunction with one another to regulate voltage applied to said respective battery and current supplied to said respective battery.

2. The battery charging system according to claim 1, wherein further said battery charging system has a switch in series with said current source to control current supplied to said batteries by switching said current source on or off.

3. The battery charging system according to claim 1, wherein said switch is timer controlled.

4. The battery charging system according to claim 1, wherein said timer controlled switch is a microcontroller.

5. The battery charging system according to claim 1, wherein further said battery charging system has means for incorporating at least one additional reference input voltage at said reference input to said band-gap voltage reference diode.

6. The battery charging system according to claim 1, wherein further each said voltage and current regulator is programmable.