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.:
Date of Patent:
Jul. 19, 2022
Filed:
Feb. 24, 2020
Rohm Co., Ltd., Kyoto, JP;
Toru Takahashi, Kyoto, JP;
Kei Nagao, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
An object of the present invention is to optimize a light-emitting driving voltage for each light-emitting portion. A light-emitting diode (LED) driver (A) includes: driver blocks () of a plurality of channels, each driver block () having a light-emitting portion connecting terminal (CH) to be connected to a light-emitting portion (LL) including one or more than one LED, the light-emitting portion being caused to emit light by a current flowing through the light-emitting portion connecting terminal to the light-emitting portion; a lowest voltage detection circuit (), detecting and outputting a lowest voltage among voltages of the light-emitting portion connecting terminals of each channel; a sample hold circuit (), comparing an output voltage (V) of the lowest voltage detection circuit with a hold voltage (V) thereof, and updating the hold voltage to the output voltage if the output voltage is lower than the hold voltage; and a feedback control circuit (), outputting a feedback signal according to the hold voltage and a predetermined reference voltage to a power supply device () providing a light emission driving voltage (Vo) to the light-emitting portions of the plurality of channels, so as to control the light emission driving voltage.