DC power conversion circuit with constant current output

• US 7,688,045 B2
• Filed: 07/12/2007
• Issued: 03/30/2010
• Est. Priority Date: 08/07/2006
• Status: Active Grant

• Current Assignee: IML International
• Original Assignee: Addtek Corporation
• Inventors: Wang, Shih-Yuan
• Primary Examiner(s): Patel, Rajnikant B
• Application Number:
  US11/776,557
• Publication Number:
  US 20080031025A1
• Time in Patent Office: 992 Days
• Field of Search: 323/222, 323/277, 323282-288, 323262-267, 361/18, 361/100, 361/101, 361/93.03, 361/152, 363/21.17, 363/17, 363/124
• US Class Current: 323/265
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators

Abstract

A DC power conversion circuit with constant current output includes a DC voltage source, a driving circuit and a control signal generator. The DC voltage source is used for providing DC power. The driving circuit includes a switch, a resistor, a diode, and an inductor. The switch has three ends, one used for receiving a control signal. Furthermore, the switch is used for conducting or cutting off a coupling between the other two ends according to the control signal. The resistor is coupled between the switch and a first grounding end. The diode has a first end and a second end coupled to a second grounding end. The inductor has a first end coupled to the first grounding end, and a second end coupled to a load circuit. The control signal generator generates the control signal for the second end of the switch according to a current of the resistor.

Claims

1. A direct-current (DC) power conversion circuit with constant current output comprising:

a DC voltage source for providing DC power;

a driving circuit comprising;

a switch having a first end coupled to the DC voltage source, a second end for receiving a control signal, and a third end, the switch used for conducting or cutting off a coupling between the first end and the third end according to the control signal received by the second end;

a resistor having a first end coupled to the third end of the switch and a second end coupled to a first grounding end;

a diode having a first end coupled to the third end of the switch and the first end of the resistor, and a second end coupled to a second grounding end; and

an inductor having a first end coupled to the first grounding end, and a second end coupled to a load circuit; and

a control signal generator having a first input end coupled to the second end of the switch, a second input end coupled to the first grounding end, and an output end coupled to the third end of the switch, the control signal generator for generating the control signal for the second end of the switch according to a current of the resistor.

2. The DC power conversion circuit of claim 1, wherein the control signal generator is a pulse width modulator.

3. The DC power conversion circuit of claim 1 further comprising a filtering capacitor coupled to the second grounding end and the second end of the inductor.

4. The DC power conversion circuit of claim 1, wherein the switch is a metal-oxide-semiconductor field-effect transistor (MOSFET transistor).

5. The DC power conversion circuit of claim 4, wherein the first end of the switch is a drain, the second end of the switch is a gate, and the third end of the switch is a source.

6. The DC power conversion circuit of claim 1, wherein the switch is a bipolar junction transistor (BJT).

7. The DC power conversion circuit of claim 6, wherein the first end of the switch is a collector, the second end of the switch is a base, and the third end of the switch is an emitter.

8. The DC power conversion circuit of claim 1, wherein the first end of the diode is N-doped, and the second end of the diode is P-doped.

9. A direct-current (DC) power conversion circuit with constant current output comprising:

a DC voltage source for providing DC power;

a driving circuit comprising;

a switch having a first end coupled to the DC voltage source, a second end for receiving a control signal, and a third end, the switch used for conducting or cutting off a coupling between the first end and the third end according to the control signal received by the second end;

a first resistor having a first end coupled to the third end of the switch and a second end coupled to a first grounding end;

a second resistor having a first end and a second end coupled to the first grounding end;

a diode having a first end coupled to the first end of the second resistor, and a second end coupled to a second grounding end; and

an inductor having a first end coupled to the first grounding end, and a second end coupled to a load circuit; and

a control signal generator coupled to the second and third ends of the switch, the first end of the second resistor, and the first grounding end, for generating the control signal for the second end of the switch according to a current of the first or second resistor.

10. The DC power conversion circuit of claim 9, wherein the control signal generator is a pulse width modulator.

11. The DC power conversion circuit of claim 9 further comprising a filtering capacitor coupled to the second grounding end and the second end of the inductor.

12. The DC power conversion circuit of claim 9, wherein the switch is a metal-oxide-semiconductor field-effect transistor (MOSFET transistor).

13. The DC power conversion circuit of claim 12, wherein the first end of the switch is a drain, the second end of the switch is a gate, and the third end of the switch is a source.

14. The DC power conversion circuit of claim 9, wherein the switch is a bipolar junction transistor (BJT).

15. The DC power conversion circuit of claim 14, wherein the first end of the switch is a collector, the second end of the switch is a base, and the third end of the switch is an emitter.

16. The DC power conversion circuit of claim 9, wherein the first end of the diode is N-doped, and the second end of the diode is P-doped.