公开(公告)号：US09907128B2

公开(公告)日：2018-02-27

申请号：US15454424

申请日：2017-03-09

Applicant: Richtek Technology Corporation

Inventor： Chang-Yu Wu ,  Wei-Ming Chiu

IPC: H05B33/08

CPC classification number: H05B33/0815 ,  H05B33/0824 ,  H05B33/0827 ,  H05B33/083 ,  H05B33/0842 ,  H05B33/0857 ,  H05B33/0887 ,  Y02B20/341

Abstract: A control chip of a driving circuit for driving a LED array shares a ground terminal with the LED array so that, without an additional winding, the driving circuit can provide a supply voltage for the control chip, implement a zero-current switching function, and implement an over-voltage protection function. Since no additional windings are needed, the related costs and the size of the driving circuit are decreased.

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.

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：US20170196055A1

公开(公告)日：2017-07-06

申请号：US15216890

申请日：2016-07-22

Applicant: RICHTEK TECHNOLOGY CORPORATION

Inventor： Tong-Cheng Jao ,  Isaac Y. Chen ,  Yi-Wei Lee ,  Wei-Ming Chiu ,  Jiun-Hung Pan

IPC: H05B33/08 ,  H05B37/02

CPC classification number: H05B33/0815 ,  H05B33/0809 ,  H05B33/0812 ,  H05B33/0827 ,  H05B33/0848 ,  H05B33/0851

Abstract: A light emitting device circuit has one or plural light emitting devices connected in series. A light emitting device driver circuit drives the light emitting device circuit according to a rectified input voltage. The light emitting device driver circuit includes a power switch and a control circuit. When the power switch is conductive, a light emitting device current flows through the light emitting device circuit and the power switch. When the power switch is not conductive, an output capacitor discharges to provide the light emitting device current. The control circuit determines whether the rectified input voltage is lower or not lower than a forward voltage plus a reference voltage according to a voltage at a reverse end of the light emitting device circuit, and control the power switch accordingly.

公开(公告)号：US09629210B2

公开(公告)日：2017-04-18

申请号：US15047154

申请日：2016-02-18

Applicant: Richtek Technology Corporation

Inventor： Chang-Yu Wu ,  Wei-Ming Chiu

IPC: H05B33/08

CPC classification number: H05B33/0815 ,  H05B33/0824 ,  H05B33/0827 ,  H05B33/083 ,  H05B33/0842 ,  H05B33/0857 ,  H05B33/0887 ,  Y02B20/341

Abstract: A control chip of a driving circuit for driving a LED array shares a ground terminal with the LED array so that, without an additional winding, the driving circuit can provide a supply voltage for the control chip, implement a zero-current switching function, and implement an over-voltage protection function. Since no additional windings are needed, the related costs and the size of the driving circuit are decreased.