Patents by Inventor Bairen Liu

Bairen Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20200389953
    Abstract: A dimming circuit for dimming a current flowing through a light emitting device, having: a multi-function pin, configured to receive a dimming signal; wherein when the dimming signal is an analog voltage signal, an amplitude of the current flowing through the light emitting device is regulated based on the dimming signal; when the dimming signal is a pulse signal and a frequency of the dimming signal is in a first frequency range, a duty cycle of the current flowing through the light emitting device is regulated based on the dimming signal; and when the dimming signal is the pulse signal and the frequency of the dimming signal is in a second frequency range, the amplitude of the current flowing through the light emitting device is regulated based on the dimming signal.
    Type: Application
    Filed: June 3, 2020
    Publication date: December 10, 2020
    Inventors: Bo Yu, Bairen Liu, Junxin Tan
  • Patent number: 10715044
    Abstract: A control circuit of a power converter providing at least a first output voltage and a second output voltage, having: a first loop control circuit, configured to provide a first error amplifying signal based on the first output voltage and a first reference voltage; a second loop control circuit, configured to provide a second error amplifying signal based on the second output voltage and a second reference voltage; a saturation detecting circuit, configured to provide a saturation indicating signal based on the first error amplifying signal and a saturation reference signal; and a first current source circuit, configured to charge an output terminal of the second error amplifier based on the saturation indicating signal.
    Type: Grant
    Filed: November 26, 2019
    Date of Patent: July 14, 2020
    Assignee: Chengdu Monolithic Power Systems Co., Ltd.
    Inventors: Bairen Liu, Shufa Jiang, Bo Yu
  • Publication number: 20200220464
    Abstract: A control circuit of a power converter providing at least a first output voltage and a second output voltage, having: a first loop control circuit, configured to provide a first error amplifying signal based on the first output voltage and a first reference voltage; a second loop control circuit, configured to provide a second error amplifying signal based on the second output voltage and a second reference voltage; a saturation detecting circuit, configured to provide a saturation indicating signal based on the first error amplifying signal and a saturation reference signal; and a first current source circuit, configured to charge an output terminal of the second error amplifier based on the saturation indicating signal.
    Type: Application
    Filed: November 26, 2019
    Publication date: July 9, 2020
    Inventors: Bairen Liu, Shufa Jiang, Bo Yu
  • Patent number: 10091846
    Abstract: A LED driving system has an energy storage component receiving an input voltage, a power switch coupled between the energy storage component and a reference ground, a first output switch coupled between the energy storage component and a first output terminal, a second output switch coupled between the energy storage component and a second output terminal, and a control circuit, wherein the first output terminal produces a first output voltage to supply power for a first LED array, the second output terminal produces a second output voltage to supply power for a second LED array, the control circuit controls a duty cycle of the first output switch according to voltages at cathode terminals of multiple LED strings in the LED array and controls a duty cycle of the second output switch according to voltages at cathode terminals of multiple LED strings in the second LED array.
    Type: Grant
    Filed: June 20, 2017
    Date of Patent: October 2, 2018
    Assignee: Chengdu Monolithic Power Systems Co., Ltd.
    Inventor: Bairen Liu
  • Patent number: 9998005
    Abstract: A voltage converter provides a positive voltage and a negative voltage with a single inductor. The voltage converter has a first switch, a second switch, a third switch and a fourth switch switched periodically, wherein each switching period comprise a first time period, a second time period and a third time period, and wherein: during the first time period, the first switch and the fourth switch are turned on, whereas the second switch and the third switch are turned off; during the second time period, the first switch and the third switch are turned on, whereas the second switch and the fourth switch are turned off; and during the third time period, the second switch and the fourth switch are turned on, whereas the first switch and the third switch are turned off.
    Type: Grant
    Filed: March 30, 2017
    Date of Patent: June 12, 2018
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Bairen Liu, Licheng Sheng, Bo Yu
  • Publication number: 20170374713
    Abstract: A LED driving system has an energy storage component receiving an input voltage, a power switch coupled between the energy storage component and a reference ground, a first output switch coupled between the energy storage component and a first output terminal, a second output switch coupled between the energy storage component and a second output terminal, and a control circuit, wherein the first output terminal produces a first output voltage to supply power for a first LED array, the second output terminal produces a second output voltage to supply power for a second LED array, the control circuit controls a duty cycle of the first output switch according to voltages at cathode terminals of multiple LED strings in the LED array and controls a duty cycle of the second output switch according to voltages at cathode terminals of multiple LED strings in the second LED array.
    Type: Application
    Filed: June 20, 2017
    Publication date: December 28, 2017
    Inventor: Bairen Liu
  • Publication number: 20170324323
    Abstract: A voltage converter provides a positive voltage and a negative voltage with a single inductor. The voltage converter has a first switch, a second switch, a third switch and a fourth switch switched periodically, wherein each switching period comprise a first time period, a second time period and a third time period, and wherein: during the first time period, the first switch and the fourth switch are turned on, whereas the second switch and the third switch are turned off; during the second time period, the first switch and the third switch are turned on, whereas the second switch and the fourth switch are turned off; and during the third time period, the second switch and the fourth switch are turned on, whereas the first switch and the third switch are turned off.
    Type: Application
    Filed: March 30, 2017
    Publication date: November 9, 2017
    Inventors: Bairen Liu, Licheng Sheng, Bo Yu
  • Patent number: 9685876
    Abstract: A method of capacitive mode detection is used in a resonant converter. The resonant converter has a square wave generator having a first switch and a second switch, a resonant network, an isolated transformer having a primary winding and a second winding, and a rectifier network providing an output DC voltage for a load. The method of capacitive mode detection includes: detecting a voltage of the secondary winding and generating a voltage detection signal; detecting an output DC voltage of the rectifier network and generating a voltage detecting threshold; comparing the voltage detection signal with the voltage detection threshold when either of the first and the second switches is turned OFF; generating a flag signal indicating whether the resonant converter enters into a capacitive mode based on the comparison result.
    Type: Grant
    Filed: December 18, 2015
    Date of Patent: June 20, 2017
    Assignee: Hangzhou MPS Semiconductor Technology Ltd.
    Inventors: Bairen Liu, Licheng Sheng, Bo Yu, Hongqiang Qin, Qiming Zhao, Naixing Kuang, Eric Yang
  • Patent number: 9485819
    Abstract: A light-emitting element driver system has a power conversion circuit, a second switch and a control circuit, the power conversion circuit has a primary circuit, a transformer, a first rectified circuit and a second rectified circuit, the second rectified circuit provides a first signal, the second switch has a first terminal coupled to an output terminal of the first rectified circuit and a second terminal to provide a second signal, when a dimming signal is in a first state, the control circuit provides a first control signal to control the power conversion circuit based on the first signal, and meanwhile provides a second control signal to control the second switch based on the second signal.
    Type: Grant
    Filed: January 22, 2015
    Date of Patent: November 1, 2016
    Assignee: CHENGDU MONOLITHIC POWER SYSTEMS CO., LTD.
    Inventors: Bairen Liu, Qiming Zhao, Licheng Sheng, Bo Yu, Hongqiang Qin, Eric Yang
  • Publication number: 20160190945
    Abstract: A method of capacitive mode detection is used in a resonant converter. The resonant converter has a square wave generator having a first switch and a second switch, a resonant network, an isolated transformer having a primary winding and a second winding, and a rectifier network providing an output DC voltage for a load. The method of capacitive mode detection includes: detecting a voltage of the secondary winding and generating a voltage detection signal; detecting an output DC voltage of the rectifier network and generating a voltage detecting threshold; comparing the voltage detection signal with the voltage detection threshold when either of the first and the second switches is turned OFF; generating a flag signal indicating whether the resonant converter enters into a capacitive mode based on the comparison result.
    Type: Application
    Filed: December 18, 2015
    Publication date: June 30, 2016
    Inventors: Bairen Liu, Licheng Sheng, Bo Yu, Hongqiang Qin, Qiming Zhao, Naixing Kuang, Eric Yang
  • Patent number: 9236796
    Abstract: A method having a negative output voltage at a negative output terminal of a charge pump tracking a positive output voltage at a positive output terminal of the charge pump. The charge pump comprises a plurality of switches and each of the plurality of switches has a serially coupled resistance. The method comprises selecting the serially coupled resistance for at least one of the plurality of switches to be different to each of the other respective serially coupled resistances associated to the other switches.
    Type: Grant
    Filed: May 29, 2014
    Date of Patent: January 12, 2016
    Assignee: Chengdu Monolithic Power Systems Co., Ltd.
    Inventors: Bairen Liu, Hongqiang Qin, Eric Yang, Song Qu, Paul Ueunten
  • Patent number: 9215769
    Abstract: The embodiments of the present circuit and method disclose a light-emitting diode (LED) driver system. The LED driver system may comprise an isolated converter and a DC/DC converter. The isolated converter may be coupled to a first input signal, and may provide a LED current and a bus voltage. The isolated converter may be configured to regulate the LED current and the bus voltage separately in accordance with a dimming signal. The DC/DC converter may comprise an input coupled to the bus voltage.
    Type: Grant
    Filed: January 25, 2012
    Date of Patent: December 15, 2015
    Assignee: Chengdu Monolithic Power Systems Co., Ltd.
    Inventors: Frank Ren, Naixing Kuang, Bairen Liu, Licheng Sheng
  • Publication number: 20150208472
    Abstract: A light-emitting element driver system has a power conversion circuit, a second switch and a control circuit, the power conversion circuit has a primary circuit, a transformer, a first rectified circuit and a second rectified circuit, the second rectified circuit provides a first signal, the second switch has a first terminal coupled to an output terminal of the first rectified circuit and a second terminal to provide a second signal, when a dimming signal is in a first state, the control circuit provides a first control signal to control the power conversion circuit based on the first signal, and meanwhile provides a second control signal to control the second switch based on the second signal.
    Type: Application
    Filed: January 22, 2015
    Publication date: July 23, 2015
    Inventors: Bairen Liu, Qiming Zhao, Licheng Sheng, Bo Yu, Hongqiang Qin, Eric Yang
  • Patent number: 9035566
    Abstract: Light emitting diode (LED) dimming and driver systems and associated methods of control are disclosed herein. In one embodiment, a system comprises a PFC stage and an LED driver stage. The LED driver stage comprises an isolated converter and a controller responsive to a dimming signal to dim LED strings for backlight. The controller also regulates an output current of the isolated converter.
    Type: Grant
    Filed: March 15, 2011
    Date of Patent: May 19, 2015
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Lei Du, Bairen Liu, Kaiwei Yao, Junming Zhang, Yuancheng Ren
  • Patent number: 8952632
    Abstract: LED driver systems and associated methods of control are disclosed herein. In one embodiment, the LED driver system comprises a converter and a controller. The controller is responsive to the LED current feedback signal and a dimming signal, and operable to generate a continuous gate drive signal to control the primary side switch of the converter. Thus, the controller regulates the output current of the converter.
    Type: Grant
    Filed: March 15, 2011
    Date of Patent: February 10, 2015
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Lei Du, Bairen Liu, Kaiwei Yao, Junming Zhang, Yuancheng Ren
  • Publication number: 20140354349
    Abstract: A method having a negative output voltage at a negative output terminal of a charge pump tracking a positive output voltage at a positive output terminal of the charge pump. The charge pump comprises a plurality of switches and each of the plurality of switches has a serially coupled resistance. The method comprises selecting the serially coupled resistance for at least one of the plurality of switches to be different to each of the other respective serially coupled resistances associated to the other switches.
    Type: Application
    Filed: May 29, 2014
    Publication date: December 4, 2014
    Applicant: Chengdu Monolithic Power Systems, Inc.
    Inventors: Bairen Liu, Hongqiang Qin, Eric Yang, Song Qu, Paul Ueunten
  • Publication number: 20120194078
    Abstract: The embodiments of the present circuit and method disclose a light-emitting diode (LED) driver system. The LED driver system may comprise an isolated converter and a DC/DC converter. The isolated converter may be coupled to a first input signal, and may provide a LED current and a bus voltage. The isolated converter may be configured to regulate the LED current and the bus voltage separately in accordance with a dimming signal. The DC/DC converter may comprise an input coupled to the bus voltage.
    Type: Application
    Filed: January 25, 2012
    Publication date: August 2, 2012
    Inventors: Frank Ren, Naixing Kuang, Bairen Liu, Licheng Sheng
  • Patent number: 8098018
    Abstract: The present invention provides a pulse dimming circuit and a method thereof. The pulse dimming circuit is compatible for both DC input signal and PWM input signal using only one circuit board, and includes a first input port, a second input port, a comparison signal generator, a comparator, a logic module, and a switch network electrically coupled to the second input port, an output terminal of the comparator, and an output terminal of the logic module.
    Type: Grant
    Filed: November 5, 2009
    Date of Patent: January 17, 2012
    Assignee: Monolithic Power Systems, Inc.
    Inventors: Bairen Liu, Lei Du, Yuancheng Ren
  • Publication number: 20110227492
    Abstract: LED driver systems and associated methods of control are disclosed herein. In one embodiment, the LED driver system comprises a converter and a controller. The controller is responsive to the LED current feedback signal and a dimming signal, and operable to generate a continuous gate drive signal to control the primary side switch of the converter. Thus, the controller regulates the output current of the converter.
    Type: Application
    Filed: March 15, 2011
    Publication date: September 22, 2011
    Inventors: Lei Du, Bairen Liu, Kaiwei Yao, Junming Zhang, Yuancheng Ren
  • Publication number: 20110227493
    Abstract: Light emitting diode (LED) dimming and driver systems and associated methods of control are disclosed herein. In one embodiment, a system comprises a PFC stage and an LED driver stage. The LED driver stage comprises an isolated converter and a controller responsive to a dimming signal to dim LED strings for backlight. The controller also regulates an output current of the isolated converter.
    Type: Application
    Filed: March 15, 2011
    Publication date: September 22, 2011
    Inventors: Lei Du, Bairen Liu, Kaiwei Yao, Junming Zhang, Yuancheng Ren