Title:
LIGHTING CIRCUIT AND VEHICULAR LAMP
Document Type and Number:
WIPO Patent Application WO/2020/045271
Kind Code:
A1
Abstract:
A semiconductor light source (502) includes a plurality of series-connected light-emitting elements (504_1 through 504_3). A drive circuit (610), upon receiving an input voltage (VIN), supplies a drive current (ILED) to the semiconductor light source (502). A bypass circuit (620) is connected to a portion (504_3) of the plurality of light-emitting elements (504_1 through 504_3) and is enabled when in a low-voltage state, thereby allowing the drive current (ILED) to be redirected therethrough. An auxiliary power supply circuit (630) is series-connected to the portion (504_3) of the plurality of light-emitting elements. A determination unit (640) determines that the portion (504_3) of the plurality of light-emitting elements has an open abnormality if an expected current does not flow in the auxiliary power supply circuit (630) when the bypass circuit (620) is disabled.
Inventors:
ICHIKAWA TOMOYUKI (JP)
Application Number:
PCT/JP2019/033005
Publication Date:
March 05, 2020
Filing Date:
August 23, 2019
Export Citation:
Assignee:
KOITO MFG CO LTD (JP)
International Classes:
B60Q1/04; B60Q11/00
Foreign References:
| JP2011192684A | 2011-09-29 | |||
| JP2016197711A | 2016-11-24 | |||
| JP2014120444A | 2014-06-30 | |||
| JP2018016191A | 2018-02-01 |
Attorney, Agent or Firm:
MORISHITA Sakaki (JP)
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