Invention Grant
- Patent Title: LED drive circuit
- Patent Title (中): LED驱动电路
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Application No.: US14768366Application Date: 2014-02-18
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Publication No.: US09277615B2Publication Date: 2016-03-01
- Inventor: Keisuke Sakai , Takashi Akiyama , Satoshi Goto , Shigehisa Watanabe , Tatsuro Yamada
- Applicant: CITIZEN HOLDINGS CO., LTD. , CITIZEN ELECTRONICS CO., LTD.
- Applicant Address: JP Tokyo JP Yamanashi
- Assignee: CITIZEN HOLDINGS CO., LTD.,CITIZEN ELECTRONICS CO., LTD.
- Current Assignee: CITIZEN HOLDINGS CO., LTD.,CITIZEN ELECTRONICS CO., LTD.
- Current Assignee Address: JP Tokyo JP Yamanashi
- Agency: RatnerPrestia
- Priority: JP2013-028854 20130218; JP2013-041683 20130304; JP2013-046329 20130308; JP2013-171090 20130821
- International Application: PCT/JP2014/053787 WO 20140218
- International Announcement: WO2014/126258 WO 20140821
- Main IPC: H05B33/08
- IPC: H05B33/08 ; H05B41/282

Abstract:
The purpose of the present invention is to provide an LED drive circuit that is capable of ameliorating insufficient lighting and improving power utilization efficiency. This LED drive circuit is an LED drive circuit wherein the number of LEDs that are turned on varies in accordance with the voltage of a commercial alternating-current power supply, the LED drive circuit being characterized by having an LED row in which multiple LEDs are connected in series, a current detection resistor for detecting a current that flows in the LED row, a bypass circuit that is connected to an intermediate connection part of the LED row, and a current-limiting circuit that is connected to an end of the LED row, wherein the bypass circuit includes a first current-limiting component, the current-limiting circuit includes a second current-limiting component, the first current-limiting component is controlled on the basis of a voltage across the ends of the current detection resistor or a voltage that is obtained by dividing the voltage across the ends of the current detection resistor, and the second current-limiting component is controlled by the divided voltage that is obtained by dividing the current detection resistor.
Public/Granted literature
- US20150382420A1 LED DRIVE CIRCUIT Public/Granted day:2015-12-31
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