Battery charging and/or DC power supply circuitry

• US 6,977,485 B1
• Filed: 12/06/2004
• Issued: 12/20/2005
• Est. Priority Date: 09/03/2004
• Status: Expired due to Fees

• Current Assignee: Mobiletron Electronics Co. Ltd.
• Original Assignee: Mobiletron Electronics Co. Ltd.
• Inventors: Wei, Chen-Ku
• Primary Examiner(s): Tibbits, Pia
• Application Number:
  US11/003,464
• Time in Patent Office: 379 Days
• Field of Search: 320/139, 320/141, 320/159, 320/160, 322/6, 363/76, 307/10.1
• US Class Current: 320/139
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: H02M 7/2176 comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output

Abstract

A battery charging and/or DC power supply circuitry employs a control circuit through an SCR drive circuit and an MOS drive circuit to control when to turn on/off a semiconductor switch unit and to turn on the semiconductor switch unit while an initial section of each positive half wave of an AC power source and an terminating section of the same are located below a predetermined level for intercepting partial power for charging. While charging a battery, the circuitry is lightweight, small-sized, and to enhance the life of the battery. While being a DC power supply, the circuitry is small-sized, high-efficiency, and low-cost.

Claims

1. A battery charging and/or DC power supply circuitry comprising:

a rectifier unit electrically connected with an AC power source for rectifying a positive full wave of said AC power source to a plurality of positive half waves;

a control circuit having a microprocessor for predetermined calculation and control;

a semiconductor switch unit having an SCR serially connected with an input terminal of an MOS switch and electrically connected with said rectifier unit;

an MOS switch drive circuit electrically connected with a control terminal of said MOS switch and said control circuit for being controlled by said control circuit to turn on/off said MOS switch;

a level-limiting circuit having an OP comparator and a Zener diode, said OP comparator having two input terminals electrically connected with said rectifier unit and said Zener diode, said Zener diode being electrically connected with an output terminal of said MOS switch, said OP comparator having an output terminal electrically connected with said control circuit and said MOS switch drive circuit for limiting a predetermined voltage level of said MOS switch; and

an SCR drive circuit having a pulse transformer and a transistor, said transistor electrically connected with said control circuit and a first side of said pulse transformer, said pulse transformer having a second side electrically connected with a gate terminal of said SCR;

wherein a battery can be electrically connected with said circuitry by its one terminal electrically connected with said MOS switch and the other terminal electrically grounded, and then said control circuit controls said MOS switch drive unit and said SCR drive circuit to further drive said semiconductor switch unit to be turned on/off and timing of charging to intercept charging current from said rectified positive half-wave power source for charging said battery.

2. The circuitry as defined in claim 1 further comprising a discharging circuit, said discharging circuit having a transistor and a plurality of resistors and electrically connected with an output terminal of said MOS switch and said control circuit for being controlled by said control circuit to be of electrical conduction for discharging.

3. The circuitry as defined in claim 1, wherein said rectifier unit is a bridging rectifier.

4. The circuitry as defined in claim 1, wherein said MOS switch is an MOSFET or a bipolar power transistor.

5. The circuitry as defined in claim 1, wherein said microprocessor comprises a programmable single chip.

6. The circuitry as defined in claim 1 further comprising a capacitor, said capacitor having a terminal electrically connected with said MOS switch and the other terminal electrically grounded to enable said circuitry to become a DC power supply.

7. A battery charging and/or DC power supply circuitry comprising:

a rectifier unit electrically connected with an AC power source for rectifying a positive full wave of said AC power source to a plurality of positive half waves;

a control circuit having a microprocessor for predetermined calculation and control;

a semiconductor switch unit having an SCR serially connected with an input terminal of an MOS switch and electrically connected with said rectifier unit;

an MOS switch drive circuit electrically connected with a control terminal of said MOS switch and said control circuit for being controlled by said control circuit to turn on/off said MOS switch;

a step-down circuit having an inductor and two diodes, said inductor having a terminal electrically connected with an output terminal of said MOS switch;

a level-limiting circuit having an OP comparator and a Zener diode, said OP comparator having two input terminals electrically connected with said rectifier unit and said Zener diode, said Zener diode being electrically connected with the other terminal of said inductor of said step-down circuit, said OP comparator having an output terminal electrically connected with said control circuit and said MOS switch drive circuit for a limiting predetermined voltage level of said MOS switch;

an SCR drive circuit having a pulse transformer and a transistor, said transistor electrically connected with said control circuit and a first side of said pulse transformer, said pulse transformer having a second side electrically connected with a gate terminal of said SCR;

an SCR maintenance circuit having two transistors Q3 and Q4, said SCR maintenance circuit being bridged over said input terminal of said MOS switch and said step-down circuit and electrically connected with said control circuit for being controlled to maintain electrical conduction of said SCR;

a timing sensing circuit having a second OP comparator, said second OP comparator having two input terminals electrically connected with said rectifier unit and said step-down circuit and an output terminal electrically connected with said control circuit; and

a current sensor;

wherein a battery can be electrically connected with said circuitry by its one terminal electrically connected with said step-down circuit and the other terminal electrically connected with said current sensor, and then said control circuit controls said MOS switch drive unit and said SCR drive circuit to further drive said semiconductor switch unit to be turned on/off and timing of charging to intercept charging current from said rectified positive half-wave power source for charging said battery;

said battery can be replaced by a capacitor, whereby said circuitry becomes a DC power supply.

8. The circuitry as defined in claim 7 further comprising a protection circuit, said protection circuit having a fuse and a second SCR and electrically connected between said AC power source and said rectifier unit, said second SCR having a gate terminal electrically connected with said control circuit.

9. The circuitry as defined in claim 7 further comprising a third SCR and a second SCR drive circuit for respectively processing said single/dual positive half-wave AC power source, said third SCR being connected in parallel with said SCR of said semiconductor switch unit, said second SCR drive circuit being electrically connected with said control circuit.

10. The circuitry as defined in claim 7, wherein said current inductor is a resistor.