Vehicular lamp

• US 7,116,052 B2
• Filed: 04/23/2004
• Issued: 10/03/2006
• Est. Priority Date: 04/28/2003
• Status: Expired due to Fees

• Current Assignee: Koito Manufacturing Company Limited
• Original Assignee: Koito Manufacturing Company Limited
• Inventors: Ito, Masayasu, Takeda, Hitoshi
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): Lie, Angela M
• Application Number:
  US10/831,090
• Publication Number:
  US 20040213015A1
• Time in Patent Office: 893 Days
• Field of Search: 315/291, 315/307, 315/312, 315/324, 315/325, 315/77, 315/82, 340/458, 362/545
• US Class Current: 315/77
• CPC Class Codes: B60Q 11/00 Arrangement of monitoring devices for devices provided for in groups B60Q1/00 - B60Q9/00
• CPC Class Codes: H05B 45/382 with galvanic isolation between input and output
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits

Abstract

Electric current supplied to light source rows of a vehicular lamp is controlled appropriately. The vehicular lamp includes: a plurality of semiconductor light emitting devices connected in parallel; a wire breakage detecting unit detecting wire breakage of each of the plurality of semiconductor light emitting devices; and an electric current supplying unit supplying a predetermined electric current to the plurality of semiconductor light emitting devices. The electric current supplying unit decreases the electric current to be supplied to the plurality of semiconductor light emitting devices when the wire breakage detecting unit detects wire breakage of at least one of the plurality of semiconductor light emitting devices.

Claims

1. A vehicular lamp, comprising:

a plurality of semiconductor light emitting devices connected in parallel;

a wire breakage detecting unit detecting wire breakage of each of said plurality of semiconductor light emitting devices;

an electric current supplying unit supplying a first electric current to said plurality of semiconductor light emitting devices,

a plurality of electric current detecting units corresponding to said plurality of semiconductor light emitting devices, each of said plurality of electric current detecting units detecting electric current flowing through corresponding one of said plurality of semiconductor light emitting devices;

an average electric current value output unit selecting at least one of said plurality of electric current detecting units corresponding to respective one(s) of said plurality of semiconductor light emitting devices of which the wire breakage is not detected by said corresponding wire breakage detecting unit, and outputting an average value of electric current detected by said selected electric current detecting unit, wherein

said average value is an average of a current flowing through all working branches, and

said electric current supplying unit decreases the electric current to be supplied to said plurality of semiconductor light emitting devices from the first electric current to a second electric current, which is lower than the first electric current, when said wire breakage detecting unit detects wire breakage of at least one of said plurality of semiconductor light emitting devices, such that the average value is maintained substantially constant when at least one of said wire breakage detecting units detects wire breakage of respective one(s) of said semiconductor light emitting devices.

2. The vehicular lamp as claimed in claim 1, wherein said electric current supplying unit decreases the electric current to be supplied to said plurality of semiconductor light emitting devices from the second electric current to a third electric current, which is lower than the second electric current, when said wire breakage detecting unit detects wire breakage of at least two of said plurality of semiconductor light emitting devices.