Light source control apparatus and light source control method

• US 9,370,082 B2
• Filed: 08/24/2015
• Issued: 06/14/2016
• Est. Priority Date: 09/29/2014
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Yoneoka, Isao, Asamura, Yoshinori, Yamamoto, Zenkou, Inoue, Haruhisa
• Primary Examiner(s): PHAM, THAI N
• Application Number:
  US14/834,100
• Publication Number:
  US 20160095194A1
• Time in Patent Office: 295 Days
• Field of Search: 315/121, 315/291, 315/294, 315/297, 315/307, 315/308
• US Class Current: 1/1
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: H05B 45/52 in a parallel array of LEDs
• CPC Class Codes: H05B 45/58 involving end of life detection of LEDs

Abstract

A controller determines whether parallel-connected light sources include a faulty light source. When a faulty light source is included, the controller controls at least one of a current supply unit and a switching unit such that a current is continuously supplied to normal light sources being light sources of the light sources except for the faulty light source.

Claims

1. A light source control apparatus that controls a plurality of light sources that are connected in parallel and emit light when supplied with a current, said apparatus comprising:

a current supply unit that collectively supplies a current to said plurality of light sources;

a first current sensing unit that senses a first current being said current collectively supplied to said plurality of light sources by said current supply unit;

a second current sensing unit that senses a second current being a current supplied to at least one of said plurality of light sources;

a switching unit having a function of stopping the supply of a current to each of said plurality of light sources; and

a controller that determines whether said plurality of light sources include a faulty light source on the basis of said first current and said second current,

wherein when said plurality of light sources include said faulty light source, said controller further controls at least one of said current supply unit and said switching unit such that a current is continuously supplied to a normal light source being a light source of said plurality of light sources except for said faulty light source.

2. The light source control apparatus according to claim 1, wherein said controller identifies said faulty light source on the basis of said first current and said second current.

3. The light source control apparatus according to claim 1, wherein

said faulty light source is a light source that has a short-circuit fault,

when said plurality of light sources include said faulty light source,

said switching unit stops the supply of a current to said faulty light source, and

said current supply unit performs a process for setting a current value of a current to be supplied to said normal light source to be smaller than or equal to a rated value of said normal light source.

4. The light source control apparatus according to claim 1, wherein

said faulty light source is a light source that has an open-circuit fault, and

when said plurality of light sources include said faulty light source, said current supply unit performs a process for setting a current value of a current to be supplied to said normal light source to be smaller than or equal to a rated value of said normal light source.

5. A light source control method to be performed by a light source control apparatus that controls a plurality of light sources that are connected in parallel and emit light when supplied with a current,

said light source control apparatus comprising:

a current supply unit that collectively supplies a current to said plurality of light sources;

a first current sensing unit that senses a first current being said current collectively supplied to said plurality of light sources by said current supply unit;

a second current sensing unit that senses a second current being a current supplied to at least one of said plurality of light sources; and

a switching unit having a function of stopping the supply of a current to each of said plurality of light sources,

said method comprising;

determining whether said plurality of light sources include a faulty light source on the basis of said first current and said second current; and

controlling, when the plurality of light sources include said faulty light source, at least one of said current supply unit and said switching unit such that a current is continuously supplied to a normal light source being a light source of said plurality of light sources except for said faulty light source.