Multi-lamp driving system

• US 7,446,485 B2
• Filed: 08/24/2005
• Issued: 11/04/2008
• Est. Priority Date: 08/24/2005
• Status: Expired due to Fees

• Current Assignee: Beyond Innovation Technology Co Ltd
• Original Assignee: Beyond Innovation Technology Co Ltd
• Inventors: Huang, Shih-Chung
• Primary Examiner(s): Vu; David Hung
• Assistant Examiner(s): Le; Tung X
• Application Number:
  US11/210,534
• Publication Number:
  US 20070052370A1
• Time in Patent Office: 1,168 Days
• Field of Search: 315/209.R, 315/246, 315254-256, 315276-279, 315/291, 315307-308, 315/312, 345/102, 345/204
• US Class Current: 315/277
• CPC Class Codes: H05B 41/282 with semiconductor devices H05B41/2806, H05B41/288, H05B41/295 take precedence
• CPC Class Codes: H05B 41/2822 using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A multi-lamp driving system for driving a first lamp and a second lamp includes a power supply circuit, and first-stage transformers. The power supply circuit is used for supplying the first and second lamps with an AC power, and first-stage transformers coupled to the power supply circuit for performing an impedance-matching function to balance lamp currents and deliver evenly distributed current to each lamp in the multi-lamp system so that each lamp provides approximately same amount of luminance. The first-stage transformers includes a first transformer have a primary side coupled to the power supply circuit and a secondary side coupled to the first lamp, and a second transformer have a primary side coupled to the first transformer and a secondary side coupled to the second lamp.

Claims

1. A multi-lamp driving system for driving a plurality of lamps, comprising:

a power supply circuit, comprising a second stage transformer, for supplying said plurality of lamps with an AC power, wherein said power supply circuit comprises a DC/AC converter for converting a DC power to a first AC power, and said second-stage transformer is coupled to said DC/AC converter for stepping up said first AC power to provide said AC power;

first-stage transformers coupled to said second stage transformer for performing an impedance-matching function to balance lamp currents and deliver evenly distributed current to each lamp in said multi-lamp system so that each lamp provides approximately same amount of luminance, wherein the first-stage transformers are voltage amplified transformers, and the second stage transformer and the first-stage transformers perform two-stage voltage amplifying; and

a voltage detection circuit coupled to a common node of said second-stage transformer and said first-stage transformer for detecting a voltage of said common node.

2. The multi-lamp driving system, as recited in claim 1, further comprises a current detection circuit coupled to said first-stage transformer for detecting a primary-side current thereof.

3. The multi-lamp driving system, as recited in claim 1, wherein said lamps are selected from a group consisting of cold cathode fluorescent lamps, metal halide lamps, sodium vapor lamps, x-ray tubes, and External Electrode Fluorescent Lamps.

4. A multi-lamp driving system for driving a first and a second lamps, comprising:

a power supply circuit for supplying said first and second lamps with an AC power;

first-stage transformers coupled to said power supply circuit for performing an impedance-matching function to balance lamp currents and deliver evenly distributed current to each lamp in said multi-lamp system so that each lamp provides approximately same amount of luminance, wherein said first-stage transformers comprises;

a first transformer having a primary side coupled to said power supply circuit and a secondary side directly coupled to a first two ends of said first lamp; and

a second transformer having a primary side coupled to said first transformer and a secondary side directly coupled to a second two ends of said second lamp, wherein said primary side of said first transformer is coupled in series or parallel to said secondary side of said second transformer; and

a voltage detection circuit coupled to a common node of said second-stage transformer and said first-stage transformer for detecting a voltage of said common node.

5. The multi-lamp driving system, as recited in claim 4, further comprises a current detection circuit coupled to said first-stage transformer for detecting a primary-side current thereof.

6. The multi-lamp driving system, as recited in claim 4, further comprises a current detection circuit coupled to said second lamp for detecting said second lamp current.

7. The multi-lamp driving system, as recited in claim 4, further comprises a current detection circuit coupled to said second lamp for detecting said second lamp current.

8. The multi-lamp driving system, as recited in claim 4, wherein said lamps are selected from a group consisting of cold cathode fluorescent lamps, metal halide lamps, sodium vapor lamps, x-ray tubes, and External Electrode Fluorescent Lamps.

9. A multi-lamp driving system for diving a first and a second lamps, comprising:

a power supply circuit for supplying said first and second lamps with an AC power;

first-stage transformers coupled to said power supply circuit for performing an impedance-matching function to balance lamp currents and deliver evenly distributed current to each lamp in said multi-lamp system so that each lamp provides approximately same amount of luminance, wherein said first-stage transformers comprises;

a first transformer having a primary side coupled to said power supply circuit and a secondary side directly coupled to a first two ends of said first lamp; and

a second transformer having a primary side coupled to said first transformer and a secondary side directly coupled to a second two ends of said second lamp, wherein said primary side of said first transformer is coupled in series to said secondary side of said second transformer; and

a voltage detection circuit coupled to a common node of said secondary side of said first-stage transformer and said second lamp for detecting a voltage of said common node.