Circuit for driving light-emitting diodes

• US 20020014862A1
• Filed: 01/16/2001
• Published: 02/07/2002
• Est. Priority Date: 01/14/2000
• Status: Active Grant

• Current Assignee: Ip Technologies LLC
• Original Assignee: Design Rite LLC
• Inventors: Fregoso, Gilbert
• Granted Patent: US 6,724,156 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/30 Driver circuits
• CPC Class Codes: H05B 45/37 Converter circuits

Abstract

A circuit efficiently drives light emitting diodes (LEDs). The circuit uses a switching regulator device instead of a standard resistor to limit current to the LEDs. The switching regulator device is in a closed loop with a current sensing device near the LED lamps. Feedback from this current sensing device switches the control method according to the current load regulating the voltage applied to the LEDs. An inductive storage device in the circuit allows the LEDs to be driven with minimal voltage input. Methods for intensifying and focusing the light produced by the LEDs driven by the circuit are also described.

Claims

1. A circuit for driving light emitting diodes comprising:

an inductive storage device, a switching regulator device, a rectifier, a filter, and a current sensing device.

2. The circuit of claim 1, wherein said inductive storage device is wire wound with an inductance between about 22 and 220 micro henries.

3. The circuit of claim 1, wherein said switching regulator device comprises:

a) a reference voltage source;

b) an oscillation circuit;

c) an error amplifier; and

d) a power MOSFET.

4. The circuit of claim 1, wherein said switching regulator device is a CMOS PWM-PFM-control step-up switching regulator.

5. The circuit of claim 1, wherein said rectifier is a Schottky diode.

6. The circuit of claim 1, wherein said current sensing device is a current driver and temperature compensation circuit comprising an error amplifier, a current sensing resistor and at least two reference voltage resistors.

7. The circuit of claim 6, wherein said current driver and temperature compensation circuit further comprises a transistor as a power driver.

8. The circuit of claim 1, further comprising a low voltage power converter circuit.

9. The circuit of claim 8, wherein said low voltage power converter circuit produces 3 volts and 20 milliamps when supplied with at least 0.8 volts input.

10. The circuit of claim 8, wherein said switching regulator device comprises:

a) a programmable reference voltage source;

b) an oscillation circuit; and

c) an error amplifier.

11. The circuit of claim 10, further comprising a super enhanced MOSFET.

12. The circuit of claim 1, wherein said circuit further comprises a power source.

13. The circuit of claim 12, wherein said power source is at least one battery.

14. The circuit of claim 12, wherein said power source is selected from the group consisting of:

one or more AAA batteries, one or more AA batteries, one or more C batteries and one or more D batteries.

15. The circuit of claim 1, wherein said circuit is at least about 70% to about 99% efficient.

16. The circuit of claim 1, wherein said circuit is at least about 90% efficient.

17. The circuit of claim 1, wherein said circuit is at least about 97% efficient.

18. The circuit of claim 1, wherein said inductive storage device is wire wound with an inductance between about 22 and 220 micro henries, wherein said switching regulator device is a CMOS PWM/PFM-control step-up switching regulator, wherein said rectifier is a Schottky diode, and wherein said current sensing device is a current driver and temperature compensation circuit comprising an error amplifier, a current sensing resistor, at least two reference voltage resistors, and a transistor as a power driver.

19. The circuit of claim 11, wherein said switching regulator device comprises a programmable reference voltage source, an oscillation circuit, and an error amplifier, and wherein said circuit further comprises a low voltage power converter circuit capable of producing 3 volts and 20 milliamps when supplied with a least 0.8 volts input and a super enhanced MOSFET.

20. A method for directing the beam pattern of at least one light emitting diode, comprising the steps of:

placing at least one primary lens in the beam path of said light emitting diode.

21. The method of claim 20, further comprising the steps of:

placing a zoom lens in a directed beam pattern from said at least one primary lens and varying the distance between said at least one primary lens and said zoom lens to focus the beam pattern of said light emitting diode.

22. An illumination device, comprising:

a circuit comprising an inductive storage device, a switching regulator device, a rectifier, a filter, and a current sensing device.

23. The illumination device of claim 22, further comprising at least one light emitting diode which is powered by said circuit.

24. The illumination device of claim 22, further comprising a power source.

25. The illumination device of claim 24, wherein said power source is at least one battery.

26. The illumination device of claim 22, wherein said inductive storage device is wire wound with an inductance between about 22 and 220 micro henries, wherein said switching regulator device is a CMOS PWM/PFM-control step-up switching regulator, wherein said rectifier is a Schottky diode, and wherein said current sensing device is a current driver and temperature compensation circuit comprising an error amplifier, a current sensing resistor, at least two reference voltage resistors, and a transistor as a power driver.

27. The illumination device of claim 22, wherein said power source is at least one AAA battery, said switching regulator device comprises a programmable reference voltage source, an oscillation circuit, and an error amplifier, and wherein said circuit further comprises a low voltage power converter circuit capable of producing 3 volts and 20 milliamps when supplied with a least 0.8 volts input and a super enhanced MOSFET.

28. The illumination device of claim 22, wherein said device is a flashlight.

29. The illumination device of claim 22, wherein said device is a headlamp.

30. The illumination device of claim 22, further comprising at least one primary lens.

31. The illumination device of claim 29, further comprising a zoom lens.

32. The illumination device of claim 29, wherein said device is a flashlight.

33. The illumination device of claim 29, wherein said device is a headlamp.

34. The illumination device of claim 30, wherein said device is a flashlight.

35. The illumination device of claim 30, wherein said device is a headlamp.