公开(公告)号：US20190159310A1

公开(公告)日：2019-05-23

申请号：US16160789

申请日：2018-10-15

Applicant: RICHTEK TECHNOLOGY CORPORATION

Inventor： Meng-Hsun Yang ,  Chi-Hsiu Lin ,  Wei-Ming Chiu

IPC: H05B33/08 ,  H02M3/157 ,  H02M1/14 ,  H02M1/08

Abstract: A light emitting device driver apparatus includes: an inductor; a power switch which switches the inductor to convert an input power to an output current for driving a light emitting device circuit; and a conversion control circuit. When a dimming signal exceeds a first dimming threshold, a reference current signal is generated according to the dimming signal, and a switch control signal controls the power switch according to a first PWM signal, such that the output current corresponds to the level of the dimming signal. When the dimming signal does not exceed the first dimming threshold, the reference current signal is clamped to a level corresponding to the first dimming threshold, and a second PWM signal is generated according to the dimming signal, wherein the second PWM signal enables the first PWM signal to generate the switch control signal to control the power switch.

公开(公告)号：US10306718B1

公开(公告)日：2019-05-28

申请号：US16160789

申请日：2018-10-15

Applicant: RICHTEK TECHNOLOGY CORPORATION

Inventor： Meng-Hsun Yang ,  Chi-Hsiu Lin ,  Wei-Ming Chiu

IPC: H05B33/00 ,  H05B33/08 ,  H02M1/08 ,  H02M1/14 ,  H02M3/157

Abstract: A light emitting device driver apparatus includes: an inductor; a power switch which switches the inductor to convert an input power to an output current for driving a light emitting device circuit; and a conversion control circuit. When a dimming signal exceeds a first dimming threshold, a reference current signal is generated according to the dimming signal, and a switch control signal controls the power switch according to a first PWM signal, such that the output current corresponds to the level of the dimming signal. When the dimming signal does not exceed the first dimming threshold, the reference current signal is clamped to a level corresponding to the first dimming threshold, and a second PWM signal is generated according to the dimming signal, wherein the second PWM signal enables the first PWM signal to generate the switch control signal to control the power switch.