High power factor switching-type battery charger

• US 4,472,672 A
• Filed: 12/13/1982
• Issued: 09/18/1984
• Est. Priority Date: 12/13/1982
• Status: Expired due to Fees

• Current Assignee: Energia Andina Limited, Motorola, Inc. (Motorola Solutions, Inc.), Fina Technologies, Inc. (Totalenergies Se)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pacholok, David R.
• Primary Examiner(s): Hickey, R. J.
• Application Number:
  US06/449,034
• Time in Patent Office: 645 Days
• Field of Search: 320/20, 320/21, 320/39, 320/53, 320/32, 320/35, 323/210, 323/242, 323/288, 363/124
• US Class Current: 320/145
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 1/4208 Arrangements for improving power factor of AC input
• CPC Class Codes: H02M 1/4291 by using a Buck converter to switch the input current
• CPC Class Codes: H02M 3/1563 without using an external clock H02M3/158 takes precedence
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y10S 320/22 Line impedance, e.g. resistor

Abstract

A switching-type charging circuit is described wherein the power factor of the circuit has been optimized. The switching-type charging circuit utilizes a dual loop feedback system to control the input and output current of the circuit. The dual feedback loop system utilizes a sinusoidal voltage reference in conjunction with a pulse width modulation circuit to force the input impedance of the circuit to appear substantially purely resistive.

Claims

1. An improved switching-type charging circuit operated from an AC power source for charging a battery wherein the operating power factor is optimized and further wherein the charging circuit includes a pulse width modulation circuit controlling a switching transistor together with a current sensing means, said charging circuit including in combination:

an electronically variable sinusoidal voltage reference means coupled to the AC input means;

a D.C. voltage reference means for generating a reference voltage related to the battery voltage and temperature;

a first feedback loop responsive to said current sensing means and said D.C. voltage reference means for controlling said electronically variable sinusoidal voltage reference means; and

a second feedback loop means responsive to said current sense means and said electronically variable voltage reference means for controlling said pulse width modulation circuit.

3. The circuit of claim 1 wherein said current sense means includes resistor and an operational amplifier.

4. The circuit of claim 1 wherein said electronically variable sinusoidal voltage reference includes a transformer, a resistor and an opto-isolator.

5. The circuit of claim 1 wherein said pulse-width modulation circuit includes a ramp generator, a comparator and an error amplifier.

6. The circuit of claim 1 wherein the DC voltage reference includes an operational amplifier, a thermistor, a zener diode and a resistor divider network.

7. The circuit of claim 1 wherein the DC voltage reference is optically isolated from the first feedback loop.

2. A method for optimizing power factor when using a switching-type power supply operating from an AC power source, for charging a battery, and having a pulse width modulation circuit controlling a switching transistor together with a current sensing means, including in combination:

deriving an electronically-variable sinusoidal voltage reference from the AC input means;

generating a DC voltage reference related to the battery voltage and temperature;

utilizing a first feedback loop responsive to said DC voltage reference and said current sensing means to control said electronically variable sinusoidal voltage reference means; and

utilizing a second feedback loop, responsive to said current sense means and said electronically variable voltage reference means to control said pulse width modulation circuit.