- Patent Title: LED drive circuit including a plurality of LEDs connected in series
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Application No.: US15564669Application Date: 2016-04-08
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Publication No.: US10044289B2Publication Date: 2018-08-07
- Inventor: Takashi Akiyama
- Applicant: CITIZEN WATCH CO., LTD. , CITIZEN ELECTRONICS CO., LTD.
- Applicant Address: JP Tokyo JP Yamanashi
- Assignee: CITIZEN WATCH CO., LTD.,CITIZEN ELECTRONICS CO., LTD.
- Current Assignee: CITIZEN WATCH CO., LTD.,CITIZEN ELECTRONICS CO., LTD.
- Current Assignee Address: JP Tokyo JP Yamanashi
- Agency: RatnerPrestia
- Priority: JP2015-079020 20150408
- International Application: PCT/JP2016/061603 WO 20160408
- International Announcement: WO2016/163533 WO 20161013
- Main IPC: H02M7/06
- IPC: H02M7/06 ; H05B37/02 ; H01L33/00 ; H02M1/00

Abstract:
The LED drive circuit has a rectifying circuit that rectifies an alternating-current voltage, an LED string including a plurality of LEDs connected in series, a first switch whose one end is connected to a cathode of an LED in a last stage of the LED string, a capacitor whose one end is connected to the other end of the first switch, a second switch that is connected between one end of the capacitor and the anode of the LED in the first stage of the LED string, and a third switch that is connected between the cathode of the LED in the last stage of the LED string and a second terminal of the rectifying circuit, and which turns on when the full-wave rectified voltage is lower than a charge start voltage and turns off when the full-wave rectified voltage is higher than or equal to the charge start voltage.
Public/Granted literature
- US20180069483A1 LED DRIVE CIRCUIT Public/Granted day:2018-03-08
Information query
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