公开(公告)号：US09655185B2

公开(公告)日：2017-05-16

申请号：US14920240

申请日：2015-10-22

Applicant: RICHTEK TECHNOLOGY CORPORATION

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

IPC: H05B33/08

CPC classification number: H05B33/083 ,  Y02B20/341 ,  Y02B20/345

Abstract: A linear LED driver comprises a transistor having an input terminal coupled to a LED. When the transistor is turned on, the LED is lighted. The linear LED driver further includes a protection circuit for judging whether an instant high voltage variation occurs or not according to at least one of the voltages of a control terminal and an output terminal of the transistor so as to achieve a protection function.

公开(公告)号：US09451661B2

公开(公告)日：2016-09-20

申请号：US15018309

申请日：2016-02-08

Applicant: Richtek Technology Corporation

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

IPC: G05F1/00 ,  H05B33/08

CPC classification number: H05B33/0845 ,  H05B33/083

Abstract: A linear LED driver includes a voltage supply terminal providing a driving voltage, at least one first transistor, each of which has an input terminal coupled to a respective LED, and a bleeder circuit. When the voltage of the output terminal of each of the at least one first transistor is lower than a first threshold and a power voltage is higher than a second threshold, the bleeder circuit will generate a bleeder current to discharge the voltage supply terminal so as to prevent the LEDs from flickering. The bleeder circuit detects the voltage of the output terminal of each of the at least one first transistor. Therefore, whether the LEDs are lighted up can be confirmed so that the bleeder current can be provided at properly time point.

Abstract translation: 线性LED驱动器包括提供驱动电压的电压供应端子，至少一个第一晶体管，每个第一晶体管具有耦合到相应LED的输入端子和泄放电路。 当所述至少一个第一晶体管中的每一个的输出端子的电压低于第一阈值并且电源电压高于第二阈值时，所述泄放电路将产生泄放电流以对所述电压供应端子进行放电，以便 防止LED闪烁。 泄放电路检测至少一个第一晶体管中的每一个的输出端子的电压。 因此，可以确认LED是否点亮，从而可以在正确的时间点设置泄放电流。

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：US10587312B1

公开(公告)日：2020-03-10

申请号：US16532531

申请日：2019-08-06

Applicant: Richtek Technology Corporation

Inventor： Tong-Cheng Jao ,  Yi-Wei Lee ,  Isaac Y. Chen

IPC: H01F27/42 ,  H04B5/00 ,  H04B15/02

Abstract: A transmission interface with noise reduction function includes a first circuit and a second circuit, for transmitting a signal from the first circuit to the second circuit or from the second circuit to the first circuit. The first circuit includes a first sub-winding and a first wire unit, and the second circuit includes a second sub-winding and a second wire unit. When an electromagnetic noise passes through the first sub-winding and the first wire unit, two loop currents are respectively generated, and the currents have opposite directions to cancel each other so as to reduce the electromagnetic noise. Or, when an emitting current corresponding to the signal flows through the first sub-winding and the first wire unit, two magnetic fields are respectively generated, and the magnetic fields have opposite directions to cancel each other so as to reduce the electromagnetic interference.