Invention Grant
- Patent Title: LED driver circuit
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Application No.: US15510431Application Date: 2015-09-11
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Publication No.: US09860944B2Publication Date: 2018-01-02
- Inventor: Takashi Akiyama , Tatsuro Yamada , Satoshi Goto
- Applicant: CITIZEN ELECTRONICS CO., LTD. , CITIZEN WATCH CO., LTD.
- Applicant Address: JP Yamanashi JP Tokyo
- Assignee: CITIZEN ELECTRONICS CO., LTD.,CITIZEN WATCH CO., LTD.
- Current Assignee: CITIZEN ELECTRONICS CO., LTD.,CITIZEN WATCH CO., LTD.
- Current Assignee Address: JP Yamanashi JP Tokyo
- Agency: RatnerPrestia
- Priority: JP2014-186800 20140912
- International Application: PCT/JP2015/075890 WO 20150911
- International Announcement: WO2016/039457 WO 20160317
- Main IPC: H05B33/08
- IPC: H05B33/08 ; H05B37/02

Abstract:
The purpose of the present invention is to provide an LED driving circuit with which it is possible to easily manage the color temperature by adjusting light. An LED driving circuit, characterized in having: a first LED group in which a plurality of first LEDs are serially connected, the first LED group contributing to emission of light having a first color temperature; a second LED group in which a plurality of second LEDs are serially connected, the second LED group contributing to emission of light having a second color temperature; a third LED group in which a plurality of second LEDs are serially connected, the second LED group contributing to emission of light having the second color temperature; and a control unit for switching, in response to an increase in a rectified output voltage, from illumination of only the first LED group to illumination of only the second LED group and then from illumination of only the second LED group to illumination of the second LED group and the third LED group, the number of first LEDs included in the first LED group being less than the number of second LEDs included in the second LED group.
Public/Granted literature
- US20170290111A1 LED DRIVER CIRCUIT Public/Granted day:2017-10-05
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