Patents by Inventor Feng Cheng Tsao
Feng Cheng Tsao 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: 7663352Abstract: A switching control circuit is provided for measuring and regulating an output current of a power converter. The power converter is operated under continuous current mode. A detection circuit generates a continuous-current signal and a peak-current signal by detecting a switching current of an inductive device. An integration circuit generates an average-current signal in response to the continuous-current signal, the peak-current signal and an off time of a switching signal. The switching control circuit generates the switching signal in response to the average-current signal. The switching signal is coupled to switch the inductive device and regulate the output current of the power converter. A time constant of the integration circuit is correlated to the switching period of the switching signal, therefore the average-current signal will be proportional to the output current.Type: GrantFiled: August 27, 2007Date of Patent: February 16, 2010Assignee: System General Corp.Inventors: Ta-yung Yang, Chuh-Ching Li, Feng-Cheng Tsao
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Patent number: 7561447Abstract: A switching regulator includes a switching device to switch a transformer from a primary-side to secondary side. A control circuit generates a switching signal for regulating output of the switching regulator. The control circuit includes a first circuit to generate a first signal and a timing signal by measuring a reflected signal of the transformer. A second circuit produces a second signal by integrating a current signal with the timing signal. The current signal represents a primary-side switching current of the transformer. A first feedback circuit produces a first feedback signal in response to the first signal and the reference signal, in which the reference signal is varied in response to the change of the second signal. Furthermore, a second feedback circuit generates a second feedback signal in response to the second signal. A switching control circuit generates the switching signal in response to the feedback signals.Type: GrantFiled: January 31, 2008Date of Patent: July 14, 2009Assignee: System General Corp.Inventors: Ta-yung Yang, Chuh-Ching Li, Feng-Cheng Tsao
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Publication number: 20090058389Abstract: A switching control circuit is provided for measuring and regulating an output current of a power converter. The power converter is operated under continuous current mode. A detection circuit generates a continuous-current signal and a peak-current signal by detecting a switching current of an inductive device. An integration circuit generates an average-current signal in response to the continuous-current signal, the peak-current signal and an off time of a switching signal. The switching control circuit generates the switching signal in response to the average-current signal. The switching signal is coupled to switch the inductive device and regulate the output current of the power converter. A time constant of the integration circuit is correlated to the switching period of the switching signal, therefore the average-current signal will be proportional to the output current.Type: ApplicationFiled: August 27, 2007Publication date: March 5, 2009Applicant: SYSTEM GENERAL CORP.Inventors: Ta-yung Yang, Chuh-Ching Li, Feng-Cheng Tsao
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Patent number: 7492613Abstract: A control circuit for detecting the reflected voltage of a transformer is provided. A detection circuit is developed for sampling the reflected voltage. Because the pulse width of the reflected voltage is narrower at light load, a bias circuit is utilized for producing a bias signal to help the reflected voltage detection. Furthermore, a blanking circuit ensures a minimum pulse width of the reflected voltage.Type: GrantFiled: November 28, 2005Date of Patent: February 17, 2009Assignee: System General Corp.Inventors: Ta-yung Yang, Chuh-Ching Li, Feng Cheng Tsao
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Patent number: 7471121Abstract: A transistor drive circuit of a power converter is developed for operating in a wide voltage range. It includes an N-type high-side transistor, a P-type high-side transistor and an N-type low-side transistor. A voltage clamp device is connected to the gate of the N-type high-side transistor to limit the maximum output voltage. A detection circuit is coupled to detect the supply voltage of the transistor drive circuit to generate a disable signal in response to the voltage level of the supply voltage. The disable signal is coupled to disable the P-type high-side transistor once the voltage level of the supply voltage is higher than a threshold voltage.Type: GrantFiled: December 21, 2006Date of Patent: December 30, 2008Assignee: System General Corp.Inventors: Ta-Yung Yang, Feng-Cheng Tsao, Chuh-Ching Li, Jesse R. Wang
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Patent number: 7466569Abstract: The present invention provides a power converter having a phase lock circuit for quasi-resonant soft switching. The power converter includes a first circuit coupled to the feedback signal to generate a switching signal for switching a switching device and regulating the output of the power converter. A second circuit is coupled to an auxiliary winding of the transformer for generating a voltage signal in response to the voltage of the transformer. A phase lock circuit generates a control signal to enable the switching signal in accordance with the voltage signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.Type: GrantFiled: November 16, 2005Date of Patent: December 16, 2008Assignee: System General CorporationInventors: Ta-Yung Yang, Rui-Hong Lu, Chuh-Ching Li, Feng-Cheng Tsao, Tso-Min Chen
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Patent number: 7426120Abstract: The present invention provides a switching control circuit having a valley voltage detector to achieve the soft switching and improve the efficiency of a power converter. The switching control circuit includes a control circuit coupled to the feedback signal to generate a switching signal. Through an output circuit, the switching signal drives a switching device for switching a transformer and regulating the output of the power converter. The valley voltage detector is coupled to an auxiliary winding of the transformer for generating a control signal in response to the voltage of the transformer. The control signal is used for enabling the switching signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.Type: GrantFiled: November 28, 2005Date of Patent: September 16, 2008Assignee: System General CorporationInventors: Ta-Yung Yang, Rui-Hong Lu, Chuh-Ching Li, Feng-Cheng Tsao, Pei-Sheng Tsu
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Publication number: 20080150503Abstract: A transistor drive circuit of a power converter is developed for operating in wide voltage range. It includes an N-type high-side transistor, a P-type high-side transistor and an N-type low-side transistor. A voltage clamp device is connected to the gate of the N-type high-side transistor to limit the maximum output voltage. A detection circuit is coupled to detect the supply voltage of the transistor drive circuit to generate a disable signal in response to the voltage level of the supply voltage. The disable signal is coupled to disable the P-type high-side transistor once the voltage level of the supply voltage is higher than a threshold voltage.Type: ApplicationFiled: December 21, 2006Publication date: June 26, 2008Inventors: Ta-Yung Yang, Feng-Cheng Tsao, Chuh-Ching Li, Jesse R. Wang
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Publication number: 20080136393Abstract: A switching regulator includes a switching device to switch a transformer from a primary-side to secondary side. A control circuit generates a switching signal for regulating output of the switching regulator. The control circuit includes a first circuit to generate a first signal and a timing signal by measuring a reflected signal of the transformer. A second circuit produces a second signal by integrating a current signal with the timing signal. The current signal represents a primary-side switching current of the transformer. A first feedback circuit produces a first feedback signal in response to the first signal and the reference signal, in which the reference signal is varied in response to the change of the second signal. Furthermore, a second feedback circuit generates a second feedback signal in response to the second signal. A switching control circuit generates the switching signal in response to the feedback signals.Type: ApplicationFiled: January 31, 2008Publication date: June 12, 2008Applicant: SYSTEM GENERAL CORP.Inventors: Ta-yung Yang, Chuh-Ching Li, Feng-Cheng Tsao
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Patent number: 7362593Abstract: A voltage-waveform detector produces a voltage-feedback signal and a discharge-time signal by multi-sampling a voltage signal of a transformer. The discharge-time signal represents a discharge time of a secondary-side switching current. A voltage-loop error amplifier amplifies the voltage-feedback signal and generates a control signal. An off-time modulator correspondingly generates a discharge-current signal and a standby signal in response to the control signal and an under-voltage signal. The under-voltage signal indicates a low supply voltage of the controller. An oscillator produces a pulse signal in response to the discharge-current signal. The pulse signal determines the off-time of the switching signal. A PWM circuit generates the switching signal in response to the pulse signal and the standby signal. The standby signal further controls the off-time of the switching signal and maintains a minimum switching frequency. The switching signal is used for regulating the output of the power supply.Type: GrantFiled: September 16, 2004Date of Patent: April 22, 2008Assignee: System General Corp.Inventors: Ta-yung Yang, Guo-Kiang Hung, Jenn-yu G. Lin, Chuh-Ching Li, Feng Cheng Tsao
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Patent number: 7352595Abstract: A switching regulator includes a switching device to switch a transformer from a primary-side to secondary side. A control circuit generates a switching signal for regulating output of the switching regulator. The control circuit includes a first circuit to generate a first signal and a timing signal by measuring a reflected signal of the transformer. A second circuit produces a second signal by integrating a current signal with the timing signal. The current signal represents a primary-side switching current of the transformer. A first feedback circuit produces a first feedback signal in response to the first signal and the reference signal, in which the reference signal is varied in response to the change of the second signal. Furthermore, a second feedback circuit generates a second feedback signal in response to the second signal. A switching control circuit generates the switching signal in response to the feedback signals.Type: GrantFiled: November 8, 2005Date of Patent: April 1, 2008Assignee: System General Corp.Inventors: Ta-yung Yang, Chuh-Ching Li, Feng Cheng Tsao
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Publication number: 20070121352Abstract: The present invention provides a switching control circuit having a valley voltage detector to achieve the soft switching and improve the efficiency of a power converter. The switching control circuit includes a control circuit coupled to the feedback signal to generate a switching signal. Through an output circuit, the switching signal drives a switching device for switching a transformer and regulating the output of the power converter. The valley voltage detector is coupled to an auxiliary winding of the transformer for generating a control signal in response to the voltage of the transformer. The control signal is used for enabling the switching signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.Type: ApplicationFiled: November 28, 2005Publication date: May 31, 2007Inventors: Ta-Yung Yang, Rui-Hong Lu, Chuh-Ching Li, Feng-Cheng Tsao, Pei-Sheng Tsu
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Publication number: 20070109820Abstract: The present invention provides a power converter having a phase lock circuit for quasi-resonant soft switching. The power converter includes a first circuit coupled to the feedback signal to generate a switching signal for switching a switching device and regulating the output of the power converter. A second circuit is coupled to an auxiliary winding of the transformer for generating a voltage signal in response to the voltage of the transformer. A phase lock circuit generates a control signal to enable the switching signal in accordance with the voltage signal. The switching signal further turns on the switching device in response to a valley voltage across the switching device.Type: ApplicationFiled: November 16, 2005Publication date: May 17, 2007Inventors: Ta-Yung Yang, Rui-Hong Lu, Chuh-Ching Li, Feng-Cheng Tsao, Tso-Min Chen
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Patent number: 7061780Abstract: The invention presents a switching control circuit for a primary-side-controlled power converter. A pattern generator produces a digital pattern to control a programmable capacitor that is connected to an oscillator, which produces frequency hopping to reduce the EMI. A voltage-waveform detector produces a voltage-feedback signal and a discharge-time signal by multi-sampling a voltage signal of a transformer. A current-waveform detector and an integrator generate a feedback signal. The integration of a current-waveform signal with a timing signal generates the average-current signal. Time constant of the integrator is correlated to the switching frequency. The oscillator generates the timing signal and a pulse signal in response to the output of a current-loop error amplifier. A PWM circuit generates the switching signal in response to the pulse signal and the output of a voltage-loop error amplifier for switching the switching device and regulating the output of the power converter.Type: GrantFiled: September 9, 2004Date of Patent: June 13, 2006Assignee: System General Corp.Inventors: Ta-yung Yang, Guo-Kiang Hung, Jenn-yu G. Lin, Feng Cheng Tsao, Chiu Shao Wei