Vehicle headlamp control system

• US 5,382,877 A
• Filed: 03/15/1993
• Issued: 01/17/1995
• Est. Priority Date: 03/19/1992
• Status: Expired due to Term

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Kawabata, Akira, Katsumata, Shuichi, Matsumoto, Hironori
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): McAndrews, Jr., Roland G.
• Application Number:
  US08/031,473
• Time in Patent Office: 673 Days
• Field of Search: 315/82, 315/83, 315/291
• US Class Current: 315/82
• CPC Class Codes: B60Q 1/1415 Dimming circuits
• 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

Disclosure is a vehicle headlamp control system having a control circuit which can control the operation and the intensity of illumination of headlamps with ease. The vehicle headlamp control system has a control circuit for controlling the operations of headlamps on a vehicle at the start of the engine. The control circuit operates to adjust the duty ratios of driving pulse currents applied to the headlamps through transistors, thereby to adjust the intensities of illumination of the headlamps. The control circuit has elements for adjusting the duty ratios. With the system, the intensities of illumination of the headlamps can be adjusted with ease.

Claims

1. A vehicle headlamp control device for controlling operation of a headlamp on a vehicle, said control device comprising:

a control circuit for controlling an intensity of illumination of said vehicle headlamp by applying a driving pulse current to said headlamp through a transistor, said control circuit including;

a frequency division counter for adjusting a duty ratio of said driving pulse current in response to a control signal to change said intensity of illumination of said head lamp.

2. A vehicle headlamp control device as claimed in claim 1, wherein said control circuit maximizes said duty ratio of said driving pulse current to maximize said intensity illumination of said headlamp in response to said control signal provided by at least one of a dimmer passing switch and a headlamp switch.

3. A vehicle headlamp control device as claimed in claim 1, further comprising a selecting switch for providing said control signal to set said duty ratio to a predetermined value.

4. A vehicle headlamp control device as claimed in claim 1, further comprising terminals for setting said duty ratio to a predetermined value by grounding at least one of said terminals with a wire harness.

5. A vehicle headlamp control device as claimed in claim 1, wherein said control circuit interrupts an application of said driving pulse current in response to an output signal of a parking brake switch.

6. A vehicle headlamp control device as claimed in claim 1, wherein said control circuit turns on said headlamp at a start of an engine thereof.