Resonant circuit for halogen lighting

• US 20060152168A1
• Filed: 01/11/2005
• Published: 07/13/2006
• Est. Priority Date: 01/11/2005
• Status: Active Grant

• Current Assignee: Vitesco Technologies USA, LLC (Continental AG)
• Original Assignee: Temic Automotive of North America, Incorporated (Continental AG)
• Inventors: O'Gorman, Patrick A., Stephens, Dennis L.
• Granted Patent: US 7,339,327 B2
• Time in Patent Office: Days
• US Class Current: 315/209.R
• CPC Class Codes: H05B 39/045 with high-frequency bridge converters H05B39/048 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 315/07 Starting and control circuits for gas discharge lamp using transistors

Abstract

An apparatus and method for driving a halogen lamp. A driving circuit is provided that is operable near a series resonance frequency. The driving circuit is coupled to the lamp in a series configuration. During startup, the circuit is driven above resonance. After the lamp has warmed up, the circuit is driven substantially at resonance. A controller is coupled to the driving circuit. The controller is operable to control the frequency of operation of the driving circuit.

Claims

1. An apparatus for driving a halogen lamp, the apparatus comprising:

a driving circuit operable near a series resonance frequency, the driving circuit coupled to the lamp in a series configuration; and

a controller coupled to the driving circuit, the controller operable to control the frequency of operation of the driving circuit.

2. The apparatus of claim 1, wherein the driving circuit is operated in an alternating current (AC) mode.

3. The apparatus of claim 2, wherein the controller controls a brightness of the lamp by skipping pulses in the AC drive current.

4. The apparatus of claim 1, wherein upon lighting of the lamp, the controller controls an inrush current to the lamp by operating the driving circuit at a frequency above the resonance frequency of the driving circuit.

5. The apparatus of claim 4, wherein after lighting of the lamp, the controller operates the driving circuit substantially at the resonance frequency of the driving circuit.

6. The apparatus of claim 1, wherein the controller controls an operating frequency of the driving circuit to regulate an output current to the lamp.

7. An apparatus for driving a halogen lamp, the apparatus comprising:

an alternating current (AC) driving circuit operable near a series resonance frequency, the driving circuit coupled to the lamp in a series configuration; and

a controller coupled to the driving circuit, the controller operable to control the frequency of operation of the driving circuit to regulate an output current, wherein

upon lighting of the lamp, the controller controls an inrush current to the lamp by operating the driving circuit at a frequency above the resonance frequency of the driving circuit, and

after lighting of the lamp, the controller operates the driving circuit substantially at the resonance frequency of the driving circuit.

8. The apparatus of claim 7, wherein the controller controls a brightness of the lamp by skipping pulses in the AC drive current.

9. The apparatus of claim 8, wherein an amplitude of the current is reduced before and after pulse skipping.

10. The apparatus of claim 7, wherein the controller operates the driving circuit substantially at the resonance frequency of the driving circuit when the resistance of the lamp has substantially stabilized.

11. A method for driving a halogen lamp, the method comprising the steps of:

providing a driving circuit for the lamp that is operable near a resonance frequency, and a controller operable to control the frequency of operation of the driving circuit;

operating the driving circuit above its resonance during startup of the lamp; and

operating the driving circuit substantially at its resonance after startup of the lamp.

12. The method of claim 11, wherein the operating steps include operating the driving circuit in an alternative current (AC) mode.

13. The method of claim 12, further comprising the step of controlling a brightness of the lamp by skipping pulses in the AC drive current.

14. The method of claim 13, wherein an amplitude of the current is reduced before and after pulse skipping.

15. The method of claim 11, wherein the operating after startup step occurs after a resistance of the lamp has substantially stabilized.

16. The method of claim 11, wherein the operating after startup step includes frequency controlling the driving circuit with PWM signals to regulate an output current to the lamp.