Circuit for enhancing power delivery of an energy source

• US 5,714,863 A
• Filed: 02/20/1996
• Issued: 02/03/1998
• Est. Priority Date: 02/20/1996
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Patil, Ashok Ramakant, Hwang, B. Chester
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): Law, Patrick B.
• Application Number:
  US08/602,523
• Time in Patent Office: 714 Days
• Field of Search: 320/1, 320/5, 320/13, 320/14, 320/50, 363/101, 323/259, 323/344
• US Class Current: 320/166
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

The power delivery of an energy source (10) is enhanced by a dual function circuit. The circuit utilizes a storage capacitor (32) to store a voltage higher than the source voltage by transferring charge from the energy source to the storage capacitor between current pulses (16), than transferring charge from the storage capacitor to the load during current pulses. This is achieved by the novel combination of a boost converter (40) operating in conjunction with a buck converter (45).

Claims

1. A circuit for enhancing power delivery of an energy source, said energy source containing an electrical charge, having a source voltage, and providing current pulses to a load, and being electrically connected to said load by a power line and a return line, said circuit comprising:

a storage capacitor having a storage voltage;

a boost mode converter coupled between said power line and said storage capacitor for charging said storage capacitor by transferring charge from said energy source to said storage capacitor between said current pulses until said storage voltage reaches a predetermined level, wherein said boost mode converter comprises;

an inductor having first and second terminals, said first terminal connected to said power line;

a boost switch coupled between said second terminal of said inductor and said return line;

a boost diode coupled between said second terminal of said inductor and said storage capacitor; and

a boost control circuit responsive to said storage voltage and the occurrence of said current pulses for controlling said boost switch; and

a means for discharging said storage capacitor by transferring charge from said storage capacitor to said load during said current pulses.

2. A circuit as defined by claim 1, wherein said boost control circuit operates said boost switch by pulse width modulation having a fixed duty cycle.

3. A circuit for enhancing power delivery of an energy source, said energy source containing an electrical charge, having a source voltage, and providing current pulses to a load, and being electrically connected to said load by a power line and a return line, said circuit comprising:

a storage capacitor having a storage voltage;

a means for charging said storage capacitor by transferring charge from said energy source to said storage capacitor between said current pulses until said storage voltage reaches a predetermined level; and

a buck converter coupled between said power line and said storage capacitor for discharging said storage capacitor by transferring charge from said storage capacitor to said load during said current pulses, wherein said buck mode converter comprises;

an inductor having first and second terminals, said first terminal connected to said power line;

a buck switch coupled between said second terminal of said inductor and said storage capacitor;

a buck diode coupled between said second terminal of said inductor and said return line; and

a buck control circuit responsive to said source voltage and said current pulses for controlling said buck switch.

4. A circuit as defined by claim 3, wherein said buck control circuit operates said buck switch by pulse width modulation having a variable duty cycle.

5. A circuit as defined by claim 3, further comprising a filter capacitor coupled in parallel with said energy source.

6. A circuit for enhancing power delivery of a battery, said battery containing an electrical charge, having a source voltage, and providing current pulses to a load, and being electrically connected to said load by a power line and a return line, said circuit comprising:

a storage capacitor referenced to said return line and having a storage voltage;

an inductor having a first terminal and a second terminal, said first terminal connected to said power line;

a buck diode and a boost switch connected in parallel between said second terminal of said inductor and said power line;

a boost diode and a buck switch coupled in parallel between said second terminal of said inductor and said storage capacitor;

a boost control circuit responsive to said storage voltage and the occurrence of said current pulses for controlling said boost switch thereby transferring charge from said battery to said storage capacitor between said current pulses until said storage voltage reaches a predetermined level; and

a buck control circuit responsive to said source voltage and the occurrence of said current pulses for controlling said buck switch thereby transferring charge from said storage capacitor to said load during said current pulses.

7. A circuit as defined by claim 6, wherein said boost control circuit operates said boost switch by pulse width modulation having a fixed duty cycle.

8. A circuit as defined by claim 6, wherein said storage voltage is substantially higher than said source voltage.

9. A circuit as defined by claim 6, wherein said buck control circuit operates said buck switch by pulse width modulation having a variable duty cycle.

10. A circuit as defined by claim 6, further comprising a filter capacitor coupled in parallel with said battery.