Resonant circuit for halogen lighting

• US 7,339,327 B2
• Filed: 01/11/2005
• Issued: 03/04/2008
• 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.
• Primary Examiner(s): VU, DAVID HUNG
• Application Number:
  US11/034,174
• Publication Number:
  US 20060152168A1
• Time in Patent Office: 1,148 Days
• Field of Search: 315/224, 315/244, 315/242, 315/DIG.5, 315/DIG.7
• US Class Current: 315/244
• 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 series-resonant driving circuit operable near a series resonance frequency, the series-resonant driving circuit coupled to the halogen lamp in a series configuration; and

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

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

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

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

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

6. The apparatus of claim 1, wherein the controller controls the frequency of operation of the series-resonant driving circuit to regulate an output current to the halogen lamp.

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

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

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

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

after lighting of the halogen lamp, the controller operates the series-resonant driving circuit substantially at the series resonance frequency.

8. The apparatus of claim 7, wherein the controller controls a brightness of the halogen 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 series-resonant driving circuit substantially at the series resonance frequency when a resistance of the halogen lamp has substantially stabilized.

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

providing (i) a series-resonant driving circuit for the halogen lamp, wherein the series-resonant driving circuit is operable near a series resonance frequency and (ii) a controller operable to control a frequency of operation of the series-resonant driving circuit;

operating the series-resonant driving circuit above the series resonance frequency during startup of the halogen lamp; and

operating the series-resonant driving circuit substantially at the series resonance frequency after startup of the halogen lamp.

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

13. The method of claim 12, further comprising the step of controlling a brightness of the halogen 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 halogen lamp has substantially stabilized.

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