Patents by Inventor Yajiang Zhu
Yajiang Zhu 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).
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Patent number: 10756633Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelope waveform formed by peak points of current pulses is in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.Type: GrantFiled: July 17, 2015Date of Patent: August 25, 2020Assignee: DIODES INCORPORATEDInventors: Shihai Zhu, Zeqiang Chen, Xuegang Ren, Yajiang Zhu
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Patent number: 9991787Abstract: A control circuit for a switch mode power supply (SMPS) includes a power switch for coupling to a primary winding of the power supply and a startup resistor coupled to an external input voltage and to a control terminal of the power switch. The control circuit also includes a controller. During startup, the controller is configured to cause the power switch to amplify a startup current from an external input voltage through the startup resistor and provide a startup power to the controller. During normal operation, the controller is configured to provide a power switch control signal to turn on and off the power switch for controlling a current flow in the primary winding and regulating an output of the power supply. The controller is configured to provide a current signal for driving an NPN power switch and to provide a voltage signal for driving an NMOS power switch.Type: GrantFiled: July 17, 2017Date of Patent: June 5, 2018Assignee: SHANGHAI SIM-BCD SEMICONDUCTOR MANUFACTURING CO., Ltd.Inventors: Meiling Zhang, Xiaoru Gao, Chao Chen, Yajiang Zhu
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Patent number: 9893626Abstract: A switch mode power supply (SMPS) has a primary-side controller configured to control a power switch for turning on and turning off a current flow in the primary winding. A secondary-side controller is coupled to the secondary winding for providing constant voltage (CV) and constant current (CC) control of the SMPS. The secondary-side controller is configured to receive an output selection signal and, based on the output selection signal, select a voltage reference signal from a plurality of voltage reference signals and select a current reference signal from a plurality of current reference signals. The secondary-side controller is configured to monitor an output voltage and an output current of the SMPS, and is configured to provide a turn-on signal to the primary-side controller for turning on the power switch upon determining that the output voltage is below the selected voltage reference signal and the output current is below the selected current reference signal.Type: GrantFiled: July 17, 2015Date of Patent: February 13, 2018Assignee: Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.Inventors: Hu Wang, Yajiang Zhu, Chao Gao, Yawei Tang
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Patent number: 9853542Abstract: A control circuit is provided for a buck converter that includes at least an inductor coupled to an output of the buck converter. The control circuit includes a power switch configured for coupling to a line voltage and configured for charging the inductor, an input line voltage sampling circuit, and a constant-voltage (CV) and constant-current (CC) control module coupled to the power switch. During a charging period of the inductor, the CV and CC control module is configured to control the power switch to provide a constant output current by maintaining a constant peak inductor current, even when the input line voltage changes. During a discharging period of the inductor, the CV and CC control module is configured to monitor the sensed output voltage to control the power switch to provide a constant output voltage.Type: GrantFiled: February 9, 2016Date of Patent: December 26, 2017Assignee: BCD SEMICONDUCTOR MANUFACTURING LIMITEDInventors: Hu Wang, Yajiang Zhu, Ruixia Fei, Shuzhuang Lv
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Publication number: 20170317577Abstract: A control circuit for a switch mode power supply (SMPS) includes a power switch for coupling to a primary winding of the power supply and a startup resistor coupled to an external input voltage and to a control terminal of the power switch. The control circuit also includes a controller. During startup, the controller is configured to cause the power switch to amplify a startup current from an external input voltage through the startup resistor and provide a startup power to the controller. During normal operation, the controller is configured to provide a power switch control signal to turn on and off the power switch for controlling a current flow in the primary winding and regulating an output of the power supply. The controller is configured to provide a current signal for driving an NPN power switch and to provide a voltage signal for driving an NMOS power switch.Type: ApplicationFiled: July 17, 2017Publication date: November 2, 2017Inventors: MEILING ZHANG, XIAORU GAO, CHAO CHEN, YAJIANG ZHU
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Patent number: 9748834Abstract: A control circuit for a switch mode power supply (SMPS) includes a power switch for coupling to a primary winding of the power supply and a startup resistor coupled to an external input voltage and to a control terminal of the power switch. The control circuit also includes a controller. During startup, the controller is configured to cause the power switch to amplify a startup current from an external input voltage through the startup resistor and provide a startup power to the controller. During normal operation, the controller is configured to provide a power switch control signal to turn on and off the power switch for controlling a current flow in the primary winding and regulating an output of the power supply. The controller is configured to provide a current signal for driving an NPN power switch and to provide a voltage signal for driving an NMOS power switch.Type: GrantFiled: February 19, 2016Date of Patent: August 29, 2017Assignee: Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.Inventors: Meiling Zhang, Xiaoru Gao, Chao Chen, Yajiang Zhu
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Patent number: 9520868Abstract: A power supply controller is provided for providing a drive current to a control terminal of a power transistor in three time intervals. The controller includes control circuits configured to control the drive current in multiple stages. During a first time interval, first drive current includes a current spike for turning on the power transistor in response to a start of the control signal pulse. During a second time interval, a second drive current includes a ramping current substantially proportional to a magnitude of a current through the power transistor. During a third time interval, current flow to the power transistor is at least partially turned off before an end of the control signal pulse.Type: GrantFiled: April 12, 2013Date of Patent: December 13, 2016Assignee: BCD Semiconductor Manufacturing LimitedInventors: Jinhua Duan, Qiang Zong, Yajiang Zhu
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Patent number: 9431895Abstract: An SMPS received a rectified periodic input line voltage and is configure to provide a regulated output. A power switch has a constant turn-on time in a given cycle of the rectified periodic input line voltage. A maximum value of the envelope of peak currents through the power switch is determined and is compared with a reference value, and the power switch turn-on time in the next cycle is adjusted accordingly. The output of the power supply is regulated to a target output value, and the current is in phase with the periodic input line voltage, resulting in a high power factor. No sampling of the line voltage is needed to maintain the high power factor. A controller chip can have as few as five pins. Alternatively, a seven-pin controller chip can have two external resistors for selecting operations in either Boundary Conduction Mode (BCM) or Discontinuous Conduction Mode (DCM).Type: GrantFiled: September 22, 2014Date of Patent: August 30, 2016Assignee: Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.Inventors: Na Liu, Zeqiang Chen, Yajiang Zhu, Jianhua Duan, Chao Deng, Zhimin Hu, Siyuan Xu
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Patent number: 9391530Abstract: A synchronous rectification circuit for a power supply includes a power switch for coupling to a secondary winding of a transformer of the power supply and an output capacitor of the power supply. The power switch includes a four-terminal MOSFET having a source, a drain, a gate, and a body. A body diode is formed by a junction between the body and the drain or by a junction between the body and the source. The body diode is coupled in parallel to the source and drain of the power transistor. A control circuit is configured to provide a control signal for controlling an on/off state of the power switch in response to a voltage condition of two terminals of the power switch. When the body diode makes a transition from reverse bias to forward bias, the control circuit causes the MOSFET to turn on, and when the forward bias voltage drops below a reference voltage, the control circuit causes the MOSFET to turn off.Type: GrantFiled: August 13, 2013Date of Patent: July 12, 2016Inventors: ShaoHua Fang, BaoZhen Chen, Qiang Zong, YaJiang Zhu
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Publication number: 20160190938Abstract: A switch mode power supply (SMPS) has a primary-side controller configured to control a power switch for turning on and turning off a current flow in the primary winding. A secondary-side controller is coupled to the secondary winding for providing constant voltage (CV) and constant current (CC) control of the SMPS. The secondary-side controller is configured to receive an output selection signal and, based on the output selection signal, select a voltage reference signal from a plurality of voltage reference signals and select a current reference signal from a plurality of current reference signals. The secondary-side controller is configured to monitor an output voltage and an output current of the SMPS, and is configured to provide a turn-on signal to the primary-side controller for turning on the power switch upon determining that the output voltage is below the selected voltage reference signal and the output current is below the selected current reference signal.Type: ApplicationFiled: July 17, 2015Publication date: June 30, 2016Inventors: HU WANG, YAJIANG ZHU, CHAO GAO, YAWEI TANG
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Publication number: 20160172964Abstract: A control circuit for a switch mode power supply (SMPS) includes a power switch for coupling to a primary winding of the power supply and a startup resistor coupled to an external input voltage and to a control terminal of the power switch. The control circuit also includes a controller. During startup, the controller is configured to cause the power switch to amplify a startup current from an external input voltage through the startup resistor and provide a startup power to the controller. During normal operation, the controller is configured to provide a power switch control signal to turn on and off the power switch for controlling a current flow in the primary winding and regulating an output of the power supply. The controller is configured to provide a current signal for driving an NPN power switch and to provide a voltage signal for driving an NMOS power switch.Type: ApplicationFiled: February 19, 2016Publication date: June 16, 2016Inventors: MEILING ZHANG, XIAORU GAO, CHAO CHEN, YAJIANG ZHU
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Publication number: 20160164408Abstract: A control circuit is provided for a buck converter that includes at least an inductor coupled to an output of the buck converter. The control circuit includes a power switch configured for coupling to a line voltage and configured for charging the inductor, an input line voltage sampling circuit, and a constant-voltage (CV) and constant-current (CC) control module coupled to the power switch. During a charging period of the inductor, the CV and CC control module is configured to control the power switch to provide a constant output current by maintaining a constant peak inductor current, even when the input line voltage changes. During a discharging period of the inductor, the CV and CC control module is configured to monitor the sensed output voltage to control the power switch to provide a constant output voltage.Type: ApplicationFiled: February 9, 2016Publication date: June 9, 2016Inventors: HU WANG, Yajiang Zhu, Ruixia Fei, Shuzhuang LV
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Patent number: 9356508Abstract: A control circuit is provided for a buck converter that includes at least an inductor coupled to an output of the buck converter. The control circuit includes a power switch configured for coupling to a line voltage and configured for charging the inductor, an input line voltage sampling circuit, and a constant-voltage (CV) and constant-current (CC) control module coupled to the power switch. During a charging period of the inductor, the CV and CC control module is configured to control the power switch to provide a constant output current by maintaining a constant peak inductor current, even when the input line voltage changes. During a discharging period of the inductor, the CV and CC control module is configured to monitor the sensed output voltage to control the power switch to provide a constant output voltage.Type: GrantFiled: September 20, 2013Date of Patent: May 31, 2016Assignee: BCD Semiconductor Manufacturing Co., Ltd.Inventors: Hu Wang, Yajiang Zhu, Ruixia Fei, Shuzhuang Lv
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Publication number: 20160087523Abstract: An SMPS received a rectified periodic input line voltage and is configure to provide a regulated output. A power switch has a constant turn-on time in a given cycle of the rectified periodic input line voltage. A maximum value of the envelope of peak currents through the power switch is determined and is compared with a reference value, and the power switch turn-on time in the next cycle is adjusted accordingly. The output of the power supply is regulated to a target output value, and the current is in phase with the periodic input line voltage, resulting in a high power factor. No sampling of the line voltage is needed to maintain the high power factor. A controller chip can have as few as five pins. Alternatively, a seven-pin controller chip can have two external resistors for selecting operations in either Boundary Conduction Mode (BCM) or Discontinuous Conduction Mode (DCM).Type: ApplicationFiled: September 22, 2014Publication date: March 24, 2016Inventors: NA LIU, Zeqiang Chen, Yajiang Zhu, Jianhua Duan, Chao Deng, Zhimin Hu, Siyuan Xu
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Patent number: 9293981Abstract: A control circuit for a switch mode power supply (SMPS) includes a power switch for coupling to a primary winding of the power supply and a startup resistor coupled to an external input voltage and to a control terminal of the power switch. The control circuit also includes a controller. During startup, the controller is configured to cause the power switch to amplify a startup current from an external input voltage through the startup resistor and provide a startup power to the controller. During normal operation, the controller is configured to provide a power switch control signal to turn on and off the power switch for controlling a current flow in the primary winding and regulating an output of the power supply. The controller is configured to provide a current signal for driving an NPN power switch and to provide a voltage signal for driving an NMOS power switch.Type: GrantFiled: August 28, 2013Date of Patent: March 22, 2016Assignee: Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.Inventors: Meiling Zhang, Xiaoru Gao, Chao Chen, Yajiang Zhu
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Publication number: 20150326131Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelope waveform formed by peak points of current pulses is in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.Type: ApplicationFiled: July 17, 2015Publication date: November 12, 2015Inventors: SHIHAI ZHU, ZEQIANG CHEN, XUEGANG REN, YAJIANG ZHU
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Patent number: 9112426Abstract: A switch mode power supply (SMPS) system includes a rectifying circuit for coupling to an AC input voltage and a transformer having a primary winding for coupling to the rectifying circuit and a secondary winding coupled to the primary winding. The system also has a power switch coupled to the primary winding and a control circuit coupled to the power switch. The control circuit is configured to control current flow in the primary winding such that an envelop waveform formed by peak points of current pulses are in phase with the magnitude of the AC input voltage. Moreover, the SMPS system is configured to provide a constant average output current.Type: GrantFiled: March 17, 2011Date of Patent: August 18, 2015Assignee: BCD Semiconductor Manufacturing CO., LTd.Inventors: Shihai Zhu, Zeqiang Chen, Xuegang Ren, Yajiang Zhu
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Patent number: 9083246Abstract: A switched mode power supply (SMPS) includes a transformer with a primary winding, a secondary winding, an auxiliary winding, and a power switch coupled to the primary winding. During one switching cycle, the auxiliary winding provides a feedback signal which includes a first voltage pulse that is induced after the power switch is turned on and a second voltage pulse that is induced after the power switch is turned off. A control circuit includes a circuit for generating a sampling signal for sampling the second voltage pulse in a switching cycle at a time that is determined based on the first voltage pulse in the same switching cycle. A sample-and-hold circuit is configured for sampling and storing the second voltage pulse in response to the sampling signal. A switching signal generating circuit is configured to generate a switching signal for controlling the power switch based on an output of the sample-and-hold circuit.Type: GrantFiled: April 20, 2011Date of Patent: July 14, 2015Assignee: BCD Semiconductor Manufacturing CO., LTd.Inventors: Qiang Zong, Huizhen Zhu, Pingan Zhao, Yajiang Zhu
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Patent number: 8964415Abstract: A switching mode power supply (SMPS) includes a rectifying device configured for converting a periodically varying input AC (alternating current) voltage into a DC (direct current) voltage, and a transformer including a primary winding, a secondary winding, and an auxiliary winding. The primary winding is coupled to the rectifying device. An input capacitor is coupled to the rectifying device and the primary winding of the transformer. A first power switch is coupled to the input capacitor. A control circuit is coupled to the first power switch and is configured to control the first power switch based on a phase or amplitude of the input AC voltage. By controlling the charging and discharging of the input capacitor, power is provided to the primary winding during a longer portion of the AC input voltage cycle, allowing the rectifier device to have a larger conduction angle to increase a power factor (PF).Type: GrantFiled: September 11, 2012Date of Patent: February 24, 2015Assignee: BCD Semiconductor Manufacturing LimitedInventors: Yajiang Zhu, Na Liu, Siyuan Xu
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Patent number: RE46369Abstract: A switching mode power supply (SMPS) includes a transformer having a primary winding, a secondary winding for providing an output voltage, and an auxiliary winding. The SMPS also includes a power switch coupled to the primary winding. A first control circuit is coupled to the secondary winding, and is configured to provide a first electrical signal to the secondary winding when the output voltage of the SMPS is less than a reference voltage during a discontinuous time, whereupon a second electrical signal is induced in the auxiliary winding. A second control circuit is coupled to the auxiliary winding and the power switch. The second control circuit is configured to regulate the output of the SMPS by controlling the power switch in response to a feedback voltage signal from the auxiliary winding, and is further configured to turn on the power switch in response to the second electrical signal.Type: GrantFiled: June 26, 2014Date of Patent: April 18, 2017Assignee: BCD Semiconductor Manufacturing LimitedInventors: Yajiang Zhu, Jia Xie, Yongbo Zhang, Chao Chen, Shuzhuang Lv