The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Patent No.:

US 9723674 B1

PDF
Full Text
Expired
Date of Patent:
Aug. 01, 2017

Filed:

Jul. 14, 2016
Applicant:

Rohm Co., Ltd., Ukyo-ku, Kyoto, JP;

Inventors:

Takeshi Nozawa, Kyoto, JP;

Shingo Haruta, Kyoto, JP;

Assignee:

ROHM CO., LTD., Ukyo-Ku, Kyoto, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B 33/08 (2006.01); G02F 1/1335 (2006.01);
U.S. Cl.
CPC ...
H05B 33/0842 (2013.01); G02F 1/133603 (2013.01); H05B 33/0815 (2013.01); H05B 33/0827 (2013.01);
Abstract

A current driver connected with light emitting diode (LED) bars of the maximum number N of channels and driving LED bars of M channels to be driven, includes: PWM input terminal configured to receive PWM-modulated external dimming pulse having duty cycle with a target light quantity common to the LED bars of the M channels; pulse measurement circuit configured to measure period and pulse width of the external dimming pulse and generate digital period data and pulse width data; interface circuit connected to external processor and configured to receive enable data and phase difference setting data; M current sources of the M channels to be driven and respectively connected with corresponding LED bars, and configured to be On-and-Off-switched in response to internal dimming pulse; and pulse generator configured to generate M internal dimming pulses and distribute the M internal dimming pulses to the M current sources.


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