公开(公告)号：US20240163987A1

公开(公告)日：2024-05-16

申请号：US18458990

申请日：2023-08-30

Applicant: Richtek Technology Corporation

Inventor： Chun-Wen Wang ,  Yi-Hua Chang ,  Hsing-Shen Huang

IPC: H05B45/10 ,  H05B45/325

CPC classification number: H05B45/10 ,  H05B45/325

Abstract: A dimming circuit is configured to generate a dimming signal to control a brightness of a light emitting device. The brightness is correlated with a duty ratio of the dimming signal. The dimming circuit is configured to count a conduction time of the dimming signal according to a programmable period count code and a programmable brightness code, based upon a fundamental frequency, wherein when the conduction time is less than a conduction time lower limit, based upon a down conversion ratio, the dimming circuit reduces a frequency of the dimming signal according to the programmable period count code and the programmable brightness code, wherein the down conversion ratio is greater than 1 to an extent where a dimming conduction time is greater than or equal to a conduction time lower threshold.