Patents by Inventor Zhibo Tao
Zhibo Tao 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).
-
Patent number: 11689113Abstract: A control circuit is configured to control a flyback circuit comprising a primary-side switch, a secondary-side rectifier and a transformer. The control circuit comprises a feedback control circuit configured to generate a secondary-side control signal based on a current ripple signal of the transformer, and at least one of a direct-current component of an output voltage signal and a direct-current component of an output current signal of a secondary side of the flyback circuit, wherein the secondary-side control signal is configured to control a turn-off of the secondary-side rectifier, an isolated transmission circuit coupled to the feedback control circuit and configured to generate a first primary-side control signal based on the secondary-side control signal, and a primary control circuit coupled to the isolated transmission circuit and configured to control a turn-on of the primary-side switch in response to receiving the first primary-side control signal.Type: GrantFiled: March 18, 2021Date of Patent: June 27, 2023Assignee: Halo Microelectronics InternationalInventors: Hai Tao, Chih-Hsien Hsieh, Kai-Fang Wei, Zhibo Tao
-
Patent number: 11606041Abstract: A synchronous rectifier control apparatus includes a continuous conduction mode detection circuit configured to receive a voltage across a synchronous rectifier switch and determine whether the synchronous rectifier switch operates in a continuous conduction mode based on a rising slope of the voltage across the synchronous rectifier switch, a turn-off timer control circuit configured to measure a conduction time of the synchronous rectifier switch and turn off the synchronous rectifier switch after the conduction time of the synchronous rectifier switch in a current cycle is substantially equal to the conduction time measured in an immediately previous cycle, and a drive voltage control circuit configured to reduce a gate drive voltage of the synchronous rectifier switch after the conduction time of the synchronous rectifier switch in the current cycle is substantially equal to the conduction time measured in the immediately previous cycle multiplied by a predetermined percentage.Type: GrantFiled: June 24, 2021Date of Patent: March 14, 2023Assignee: Halo Microelectronics InternationalInventors: Kai-Fang Wei, Zhibo Tao, Yueguo Hao
-
Publication number: 20220416675Abstract: A synchronous rectifier control apparatus includes a continuous conduction mode detection circuit configured to receive a voltage across a synchronous rectifier switch and determine whether the synchronous rectifier switch operates in a continuous conduction mode based on a rising slope of the voltage across the synchronous rectifier switch, a turn-off timer control circuit configured to measure a conduction time of the synchronous rectifier switch and turn off the synchronous rectifier switch after the conduction time of the synchronous rectifier switch in a current cycle is substantially equal to the conduction time measured in an immediately previous cycle, and a drive voltage control circuit configured to reduce a gate drive voltage of the synchronous rectifier switch after the conduction time of the synchronous rectifier switch in the current cycle is substantially equal to the conduction time measured in the immediately previous cycle multiplied by a predetermined percentage.Type: ApplicationFiled: June 24, 2021Publication date: December 29, 2022Inventors: Kai-Fang Wei, Zhibo Tao, Yueguo Hao
-
Publication number: 20220302849Abstract: A control circuit is configured to control a flyback circuit comprising a primary-side switch, a secondary-side rectifier and a transformer. The control circuit comprises a feedback control circuit configured to generate a secondary-side control signal based on a current ripple signal of the transformer, and at least one of a direct-current component of an output voltage signal and a direct-current component of an output current signal of a secondary side of the flyback circuit, wherein the secondary-side control signal is configured to control a turn-off of the secondary-side rectifier, an isolated transmission circuit coupled to the feedback control circuit and configured to generate a first primary-side control signal based on the secondary-side control signal, and a primary control circuit coupled to the isolated transmission circuit and configured to control a turn-on of the primary-side switch in response to receiving the first primary-side control signal.Type: ApplicationFiled: March 18, 2021Publication date: September 22, 2022Inventors: Hai Tao, Chih-Hsien Hsieh, Kai-Fang Wei, Zhibo Tao
-
Patent number: 11005377Abstract: In one embodiment, a power supply controller, or alternately a semiconductor device having a power supply controller, may have a first circuit configured to form a sense signal that is representative of a signal from an auxiliary winding of a transformer. A feedback circuit may be configured to allow the sense signal to increase in response to a turn-off of the power switch, to subsequently detect a second increase of the sense signal prior to subsequently turning on the power switch, and to form a feedback signal as a value of the sense signal responsively to the second increase of the sense signal.Type: GrantFiled: December 17, 2019Date of Patent: May 11, 2021Assignee: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo Tao, Chih-Hsien Hsieh, Yue-Hong Tang
-
Patent number: 10897206Abstract: A switched-mode power supply with near valley switching includes a quasi-resonant converter. The converter includes a switch element that is turned on not only at the valley, but also in a window range of ?tNVW close to the valley, where the voltage across the switch element is at its minimum. This advantageously reduces switching loss and maintains a balance between efficiency and frequency variation.Type: GrantFiled: February 20, 2019Date of Patent: January 19, 2021Assignee: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo Tao, Jung-Sheng Chen, Li Lin, Kai-Fang Wei, Chih-Hsien Hsieh, Hangseok Choi, Yue-Hong Tang
-
Publication number: 20200127573Abstract: In one embodiment, a power supply controller, or alternately a semiconductor device having a power supply controller, may have a first circuit configured to form a sense signal that is representative of a signal from an auxiliary winding of a transformer. A feedback circuit may be configured to allow the sense signal to increase in response to a turn-off of the power switch, to subsequently detect a second increase of the sense signal prior to subsequently turning on the power switch, and to form a feedback signal as a value of the sense signal responsively to the second increase of the sense signal.Type: ApplicationFiled: December 17, 2019Publication date: April 23, 2020Applicant: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo TAO, Chih-Hsien HSIEH, Yue-Hong TANG
-
Patent number: 10560027Abstract: In one embodiment, a power supply controller, or alternately a semiconductor device having a power supply controller, may have a first circuit configured to form a sense signal that is representative of a signal from an auxiliary winding of a transformer. A feedback circuit may be configured to allow the sense signal to increase in response to a turn-off of the power switch, to subsequently detect a second increase of the sense signal prior to subsequently turning on the power switch, and to form a feedback signal as a value of the sense signal responsively to the second increase of the sense signal.Type: GrantFiled: February 4, 2019Date of Patent: February 11, 2020Assignee: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo Tao, Chih-Hsien Hsieh, Yue-Hong Tang
-
Patent number: 10523110Abstract: A synchronous rectifier (SR) controller includes a controller having an input adapted to be coupled to a drain of an SR transistor, and an output for providing a drive signal in response thereto, a gate driver having an input coupled to the output of the controller, and an output adapted to be coupled to a gate of the SR transistor for providing a gate signal thereto, a first transistor having a drain coupled to the gate terminal, a gate, and a source coupled to ground, and a protection circuit having an input coupled to the drain terminal, and an output coupled to the gate of the first transistor. The protection circuit is responsive to a voltage on the drain terminal exceeding a first voltage to provide a voltage on the gate of the first transistor greater than a turn-on voltage and less than an overvoltage of the first transistor.Type: GrantFiled: May 8, 2018Date of Patent: December 31, 2019Assignee: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Zhibo Tao, Lei Chen, Kai-Fang Wei
-
Patent number: 10516341Abstract: Synchronous rectifier gate voltage boost method and system. At least some of the example embodiments are methods of operating a power converter to create an output voltage, including storing energy in a field of a main transformer arranged for flyback operation, the storing during periods of time when a primary switch is conductive and current flows through a primary winding of the transformer; and then transferring energy from the field of the main transformer to the output voltage on a secondary side of the power converter; activating a secondary rectifier (SR) switch on the secondary side of the power converter during periods of time when the primary switch is non-conductive, the activating by: driving a gate of the SR switch without boost if the output voltage is above a first threshold; and driving the gate of the SR switch with boost if the output voltage is below the first threshold.Type: GrantFiled: December 18, 2018Date of Patent: December 24, 2019Assignee: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Jian Ming Fu, Chou-Sheng Wang, Zhibo Tao
-
Publication number: 20190181763Abstract: In one embodiment, a power supply controller, or alternately a semiconductor device having a power supply controller, may have a first circuit configured to form a sense signal that is representative of a signal from an auxiliary winding of a transformer. A feedback circuit may be configured to allow the sense signal to increase in response to a turn-off of the power switch, to subsequently detect a second increase of the sense signal prior to subsequently turning on the power switch, and to form a feedback signal as a value of the sense signal responsively to the second increase of the sense signal.Type: ApplicationFiled: February 4, 2019Publication date: June 13, 2019Applicant: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo TAO, Chih-Hsien HSIEH, Yue-Hong TANG
-
Publication number: 20190181765Abstract: A switched-mode power supply with near valley switching includes a quasi-resonant converter. The converter includes a switch element that is turned on not only at the valley, but also in a window range of ?tNVW close to the valley, where the voltage across the switch element is at its minimum. This advantageously reduces switching loss and maintains a balance between efficiency and frequency variation.Type: ApplicationFiled: February 20, 2019Publication date: June 13, 2019Applicant: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo TAO, Jung-Sheng CHEN, Li LIN, Kai-Fang WEI, Chih-HSIEN HSIEH, Hangseok CHOI, Yue-Hong TANG
-
Patent number: 10256735Abstract: A switched-mode power supply with near valley switching includes a quasi-resonant converter. The converter includes a switch element that is turned on not only at the valley, but also in a window range of ?tNVW close to the valley, where the voltage across the switch element is at its minimum. This advantageously reduces switching loss and maintains a balance between efficiency and frequency variation.Type: GrantFiled: February 25, 2016Date of Patent: April 9, 2019Assignee: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo Tao, Jung-Sheng Chen, Li Lin, Kai-Fang Wei, Chih-Hsien Hsieh, Hangseok Choi, Yue-Hong Tang
-
Publication number: 20190097521Abstract: A synchronous rectifier (SR) controller includes a controller having an input adapted to be coupled to a drain of an SR transistor, and an output for providing a drive signal in response thereto, a gate driver having an input coupled to the output of the controller, and an output adapted to be coupled to a gate of the SR transistor for providing a gate signal thereto, a first transistor having a drain coupled to the gate terminal, a gate, and a source coupled to ground, and a protection circuit having an input coupled to the drain terminal, and an output coupled to the gate of the first transistor. The protection circuit is responsive to a voltage on the drain terminal exceeding a first voltage to provide a voltage on the gate of the first transistor greater than a turn-on voltage and less than an overvoltage of the first transistor.Type: ApplicationFiled: May 8, 2018Publication date: March 28, 2019Applicant: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Zhibo TAO, Lei CHEN, Kai-Fang WEI
-
Patent number: 10236779Abstract: In one embodiment, a power supply controller, or alternately a semiconductor device having a power supply controller, may have a first circuit configured to form a sense signal that is representative of a signal from an auxiliary winding of a transformer. A feedback circuit may be configured to allow the sense signal to increase in response to a turn-off of the power switch, to subsequently detect a second increase of the sense signal prior to subsequently turning on the power switch, and to form a feedback signal as a value of the sense signal responsively to the second increase of the sense signal.Type: GrantFiled: March 29, 2017Date of Patent: March 19, 2019Assignee: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo Tao, Chih-Hsien Hsieh, Yue-Hong Tang
-
Patent number: 10177645Abstract: A circuit includes a drain detect circuit. The drain detect circuit receives a sense signal from a secondary side of a power converter circuit, determines, using voltage values of the sense signal, whether a primary side switch of the power converter circuit has been turned on, and assert a switch on detect signal in response to determining that the primary side switch has been turned on. The circuit may assert an enable signal in response to the assertion of the switch on detect signal, and de-asserts the enable signal in response to an assertion of a control signal. The control signal may only allowed to be asserted when the enable signal is asserted. The control signal may control a Synchronous Rectifier device. The power converter circuit may be a flyback converter, and the primary side switch may control a current into a primary-side coil of a transformer.Type: GrantFiled: October 20, 2017Date of Patent: January 8, 2019Assignee: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Zhibo Tao, Taesung Kim, BongGeun Chung, Gwanbon Koo, Lei Chen
-
Patent number: 10158298Abstract: A method for communicating with a power converter comprises initiating a communication sequence by sensing a first distortion of a sensed waveform during a discharge period of a first power transfer cycle of the power converter. The sensed waveform is proportional to a secondary current of the power converter. At a primary side of the power converter, a data bit is received from a secondary side of the power converter, by sensing a second distortion to represent one state of the data bit and sending an absence of the second distortion to represent another state of the data bit. The secondary distortion is applied to the secondary current during the discharge period of a subsequent power transfer cycle.Type: GrantFiled: April 27, 2018Date of Patent: December 18, 2018Assignee: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Li Lin, Zhibo Tao, Chih Hsien Hsieh, Yue-Hong Tang, Ching Wen Fu, Ju-Hyun Kim
-
Publication number: 20180358885Abstract: A circuit includes a drain detect circuit. The drain detect circuit receives a sense signal from a secondary side of a power converter circuit, determines, using voltage values of the sense signal, whether a primary side switch of the power converter circuit has been turned on, and assert a switch on detect signal in response to determining that the primary side switch has been turned on. The circuit may assert an enable signal in response to the assertion of the switch on detect signal, and de-asserts the enable signal in response to an assertion of a control signal. The control signal may only allowed to be asserted when the enable signal is asserted. The control signal may control a Synchronous Rectifier device. The power converter circuit may be a flyback converter, and the primary side switch may control a current into a primary-side coil of a transformer.Type: ApplicationFiled: October 20, 2017Publication date: December 13, 2018Applicant: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Zhibo TAO, Taesung KIM, BongGeun CHUNG, Gwanbon KOO, Lei CHEN
-
Publication number: 20180248490Abstract: A method for communicating with a power converter comprises initiating a communication sequence by sensing a first distortion of a sensed waveform during a discharge period of a first power transfer cycle of the power converter. The sensed waveform is proportional to a secondary current of the power converter. At a primary side of the power converter, a data bit is received from a secondary side of the power converter, by sensing a second distortion to represent one state of the data bit and sending an absence of the second distortion to represent another state of the data bit. The secondary distortion is applied to the secondary current during the discharge period of a subsequent power transfer cycle.Type: ApplicationFiled: April 27, 2018Publication date: August 30, 2018Applicant: SEMICONDUCTOR COMPONENTS INDUSTRIES, LLCInventors: Li LIN, Zhibo TAO, Chih Hsien HSIEH, Yue-Hong TANG, Ching Wen FU, Ju-Hyun KIM
-
Patent number: 10027165Abstract: An electrical circuit for a power supply includes a primary-side controller integrated circuit (IC) that outputs a drive signal on a switch pin to control a switching operation of a switch that is coupled to a primary winding of a transformer. The primary-side controller IC places the switch pin at high impedance during a sense window and turns on the switch in response to sensing a dynamic detection signal on the switch pin during the sense window. The dynamic detection signal is induced by a secondary-side controller IC by controlling switching of a switch that is coupled to a secondary winding of the transformer when the output voltage drops below a predetermined threshold during standby or other low load conditions.Type: GrantFiled: May 19, 2017Date of Patent: July 17, 2018Assignee: FAIRCHILD SEMICONDUCTOR CORPORATIONInventors: Zhibo Tao, Zhao-Jun Wang, Chih-Hsien Hsieh, Li Lin