System and method for operating incandescent lamps with high voltage source

• US 6,307,330 B1
• Filed: 04/25/2000
• Issued: 10/23/2001
• Est. Priority Date: 04/25/2000
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: So, Lingkon
• Primary Examiner(s): Philogene, Haissa
• Application Number:
  US09/558,263
• Time in Patent Office: 546 Days
• Field of Search: 315/291, 315/307, 315/224, 315/311, 315/77, 315/78, 315/DIG.4, 307/10.1, 307/10.8
• US Class Current: 315/291
• CPC Class Codes: H05B 39/047 with pulse width modulation from a DC power source
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A system and method is provided for operating incandescent lamps with a high voltage source in a motor vehicle. The system includes at least one pulse width modulation circuit having an incandescent lamp electrically connected to a high voltage source. The system also includes a generator electrically connected to the at least one pulse width modulation circuit for generating a pulse width modulation signal to modulate a voltage of the high voltage source to a voltage rating of the incandescent lamp.

Claims

1. A system for operating incandescent lamps with a high voltage source in a motor vehicle comprising:

at least one pulse width modulation circuit having an incandescent lamp electrically connected to a high voltage direct current source, the high voltage direct current source having a voltage rating higher than a voltage rating of said incandescent lamp; and

a generator electrically connected to said at least one pulse width modulation circuit for generating a pulse width modulation signal to modulate a voltage of the high voltage direct current source reduced to the voltage rating of said incandescent lamp.

2. A system as set forth in claim 1 wherein said generator is a pulse width modulation generator.

3. A system as set forth in claim 1 wherein said generator has a variable duty cycle.

4. A system as set forth in claim 1 wherein said generator is a square wave generator.

5. A system as set forth in claim 4 wherein said square wave generator produces an 800 Hz square wave signal.

6. A system as set forth in claim 1 including a voltage sensor electrically interconnecting said incandescent lamp and said generator.

7. A system as set forth in claim 1 including a current sensor electrically interconnecting said pulse width modulation circuit and said generator.

8. A system as set forth in claim 1 wherein said incandescent lamp has a voltage rating of 12.8 v and the voltage source has a voltage of 42 v.

9. A system for operating incandescent lamps with a high voltage source in a motor vehicle comprising:

at least one pulse width modulation circuit having an incandescent lamp electrically connected to a high voltage source;

a generator electrically connected to said at least one pulse width modulation circuit for generating a pulse width modulation signal to modulate a voltage of the high voltage source to a voltage rating of said incandescent lamp;

a current sensor electrically interconnecting said pulse width modulation circuit and said generator; and

an amplitude controller electrically interconnecting said current sensor and said generator and said pulse width modulation circuit.

10. A system for operating incandescent lamps with a high voltage source in a motor vehicle comprising:

at least one pulse width modulation circuit having an incandescent lamp electrically connected to a high voltage source;

a generator electrically connected to said at least one pulse width modulation circuit for generating a pulse width modulation signal to modulate a voltage of the high voltage source to a voltage rating of said incandescent lamp; and

wherein said at least one pulse width modulation circuit includes an amplitude controller and a pulse width modulation device electrically interconnecting said amplitude controller and said incandescent lamp.

11. A system for operating incandescent lamps with a high voltage source in a motor vehicle comprising:

at least one pulse width modulation circuit having an incandescent lamp electrically connected to a high voltage source;

a generator electrically connected to said at least one pulse width modulation circuit for generating a pulse width modulation signal to modulate a voltage of the high voltage source to a voltage rating of said incandescent lamp; and

an octal counter electrically interconnecting said generator and said pulse width modulation circuit.

12. A method for operating incandescent lamps with a high voltage source in a motor vehicle, said method comprising the steps of:

providing at least one pulse width modulation (PWM) circuit having an incandescent lamp electrically connected to a high voltage direct current source, the high voltage direct current source having a voltage rating higher than a voltage rating of the incandescent lamp;

providing a generator electrically connected to the at least one pulse width modulation circuit; and

generating a pulse width modulation signal from the generator and modulating a voltage of the high voltage direct current source and reducing the voltage to the voltage rating of the incandescent lamp.

13. A method as set forth in claim 12 including the step of limiting current to the incandescent lamp during an initial turn On of the incandescent lamp.

14. A method as set forth in claim 13 wherein said step of limiting comprises operating the PWM circuit with a constant duty cycle during the initial turn On.

15. A method as set forth in claim 14 including the step of operating a PWM device of the PWM circuit in a linear mode such that power and energy supplied to the incandescent lamp is small during the initial turn On and gradually increased to a rated value of the incandescent lamp within a period of time.

16. A method as set forth in claim 12 including the step of varying the duty cycle generated by the generator.

17. A method as set forth in claim 16 wherein said step of varying comprises varying the duty cycle by the generator inversely proportional to the voltage.

18. A method as set forth in claim 12 wherein said generator is a pulse width modulation generator.

19. A method for operating incandescent lamps with a high voltage source in a motor vehicle, said method comprising the steps of:

providing at least one pulse width modulation (PWM) circuit having an incandescent lamp electrically connected to a high voltage source;

providing a generator electrically connected to the at least one pulse width modulation circuit;

generating a pulse width modulation signal from the generator and modulating a voltage of the high voltage source to a voltage rating of the incandescent lamp; and

reducing an amplitude of the PWM signal by an amplitude controller to zero to turn Off a PWM device of the PWM circuit when over current of a predetermined amplitude occurs.

20. A method for operating incandescent lamps with a high voltage source in a motor vehicle, said method comprising the steps of:

providing at least one pulse width modulation (PWM) circuit having an incandescent lamp electrically connected to a high voltage source;

providing a generator electrically connected to the at least one pulse width modulation circuit;

generating a pulse width modulation signal from the generator and modulating a voltage of the high voltage source to a voltage rating of the incandescent lamp; and

dimming the incandescent lamp by decreasing an amplitude of the PWM signal by an amplitude controller over a period of time.