Patents by Inventor Kuang-Ming Chang
Kuang-Ming Chang 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: 10763221Abstract: A high voltage (HV) converter implemented on a printed circuit board (PCB) includes a double diffused metal oxide semiconductor (DMOS) package comprising a lead frame and a main DMOS chip. The lead frame includes a gate section electrically connected to a gate electrode of the main DMOS chip, a source section electrically connected to a source electrode of the main DMOS chip and a drain section electrically connected to a drain electrode of the main DMOS chip. The PCB layout includes a large area source copper pad attached to and overlapping the source section of the DMOS package to facilitate cooling and a small area drain copper pad attached to and overlapping the drain section of the DMOS package to reduce electromagnetic interference (EMI) noise.Type: GrantFiled: August 29, 2019Date of Patent: September 1, 2020Assignee: ALPHA AND OMEGA SEMICONDUCTOR (CAYMAN), LTD.Inventors: Zhiqiang Niu, Kuang Ming Chang, Lin Chen, Ning Sun, QiHong Huang, Tzu-Hsin Lu
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Publication number: 20190385953Abstract: A high voltage (HV) converter implemented on a printed circuit board (PCB) includes a double diffused metal oxide semiconductor (DMOS) package comprising a lead frame and a main DMOS chip. The lead frame includes a gate section electrically connected to a gate electrode of the main DMOS chip, a source section electrically connected to a source electrode of the main DMOS chip and a drain section electrically connected to a drain electrode of the main DMOS chip. The PCB layout includes a large area source copper pad attached to and overlapping the source section of the DMOS package to facilitate cooling and a small area drain copper pad attached to and overlapping the drain section of the DMOS package to reduce electromagnetic interference (EMI) noise.Type: ApplicationFiled: August 29, 2019Publication date: December 19, 2019Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Zhiqiang Niu, Kuang Ming Chang, Lin Chen, Ning Sun, QiHong Huang, Tzu-Hsin Lu
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Patent number: 10438900Abstract: A high voltage (HV) converter implemented on a printed circuit board (PCB) includes a double diffused metal oxide semiconductor (DMOS) package comprising a lead frame and a main DMOS chip. The lead frame includes a gate section electrically connected to a gate electrode of the main DMOS chip, a source section electrically connected to a source electrode of the main DMOS chip and a drain section electrically connected to a drain electrode of the main DMOS chip. The PCB layout includes a large area source copper pad attached to and overlapping the source section of the DMOS package to facilitate cooling and a small area drain copper pad attached to and overlapping the drain section of the DMOS package to reduce electromagnetic interference (EMI) noise.Type: GrantFiled: March 29, 2018Date of Patent: October 8, 2019Assignee: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Zhiqiang Niu, Kuang Ming Chang, Lin Chen, Ning Sun, QiHong Huang
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Publication number: 20190304924Abstract: A high voltage (HV) converter implemented on a printed circuit board (PCB) includes a double diffused metal oxide semiconductor (DMOS) package comprising a lead frame and a main DMOS chip. The lead frame includes a gate section electrically connected to a gate electrode of the main DMOS chip, a source section electrically connected to a source electrode of the main DMOS chip and a drain section electrically connected to a drain electrode of the main DMOS chip. The PCB layout includes a large area source copper pad attached to and overlapping the source section of the DMOS package to facilitate cooling and a small area drain copper pad attached to and overlapping the drain section of the DMOS package to reduce electromagnetic interference (EMI) noise.Type: ApplicationFiled: March 29, 2018Publication date: October 3, 2019Applicant: Alpha and Omega Semiconductor (Cayman) Ltd.Inventors: Zhiqiang Niu, Kuang Ming Chang, Lin Chen, Ning Sun, QiHong Huang, Tzu-Hsin Lu
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Patent number: 10250152Abstract: A flyback converter implements a Forced Zero Voltage Switching (ZVS) timing control by detecting a positive current excursion of the secondary winding current as the synchronous rectifier turn off trigger. The synchronous rectifier switch is turned on near the end of the switching cycle or the on duration is extended to develop a current ripple on the secondary winding current. The control circuit of the flyback converter detects a positive current excursion on the secondary winding current to turn off the synchronous rectifier and to start the next switching cycle. At this point, the voltage across the primary switch has been discharged and the primary switch can be turned on with zero drain-to-source voltage. In other embodiments, zero voltage switching for the off-transition of the primary switch is realized by coupling a capacitor across the primary switch or by coupling a capacitor across the primary winding, or both.Type: GrantFiled: May 4, 2018Date of Patent: April 2, 2019Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Kuang Ming Chang, Lin Chen, Qihong Huang
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Publication number: 20180254712Abstract: A flyback converter implements a Forced Zero Voltage Switching (ZVS) timing control by detecting a positive current excursion of the secondary winding current as the synchronous rectifier turn off trigger. The synchronous rectifier switch is turned on near the end of the switching cycle or the on duration is extended to develop a current ripple on the secondary winding current. The control circuit of the flyback converter detects a positive current excursion on the secondary winding current to turn off the synchronous rectifier and to start the next switching cycle. At this point, the voltage across the primary switch has been discharged and the primary switch can be turned on with zero drain-to-source voltage. In other embodiments, zero voltage switching for the off-transition of the primary switch is realized by coupling a capacitor across the primary switch or by coupling a capacitor across the primary winding, or both.Type: ApplicationFiled: May 4, 2018Publication date: September 6, 2018Inventors: Kuang Ming Chang, Lin Chen, Qihong Huang
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Patent number: 9998021Abstract: A flyback converter implements a Forced Zero Voltage Switching (ZVS) timing control by detecting a positive current excursion of the secondary winding current as the synchronous rectifier turn off trigger. The synchronous rectifier switch is turned on near the end of the switching cycle or the on duration is extended to develop a current ripple on the secondary winding current. The control circuit of the flyback converter detects a positive current excursion on the secondary winding current to turn off the synchronous rectifier and to start the next switching cycle. At this point, the voltage across the primary switch has been discharged and the primary switch can be turned on with zero drain-to-source voltage. In other embodiments, zero voltage switching for the off-transition of the primary switch is realized by coupling a capacitor across the primary switch or by coupling a capacitor across the primary winding, or both.Type: GrantFiled: October 25, 2016Date of Patent: June 12, 2018Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Kuang Ming Chang, Lin Chen, Qihong Huang
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Publication number: 20180115252Abstract: A flyback converter implements a Forced Zero Voltage Switching (ZVS) timing control by detecting a positive current excursion of the secondary winding current as the synchronous rectifier turn off trigger. The synchronous rectifier switch is turned on near the end of the switching cycle or the on duration is extended to develop a current ripple on the secondary winding current. The control circuit of the flyback converter detects a positive current excursion on the secondary winding current to turn off the synchronous rectifier and to start the next switching cycle. At this point, the voltage across the primary switch has been discharged and the primary switch can be turned on with zero drain-to-source voltage. In other embodiments, zero voltage switching for the off-transition of the primary switch is realized by coupling a capacitor across the primary switch or by coupling a capacitor across the primary winding, or both.Type: ApplicationFiled: October 25, 2016Publication date: April 26, 2018Inventors: Kuang Ming Chang, Lin Chen, Qihong Huang
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Patent number: 9899931Abstract: A flyback converter implements a Forced Zero Voltage Switching (ZVS) timing control by detecting a positive current excursion of the secondary winding current as the synchronous rectifier turn off trigger. The synchronous rectifier switch is turned on near the end of the switching cycle or the on duration is extended to develop a current ripple on the secondary winding current. The control circuit of the flyback converter detects a positive current excursion on the secondary winding current to turn off the synchronous rectifier and to start the next switching cycle. At this point, the voltage across the primary switch has been discharged and the primary switch can be turned on with zero drain-to-source voltage. In other embodiments, zero voltage switching for the off-transition of the primary switch is realized by coupling a capacitor across the primary switch or by coupling a capacitor across the primary winding, or both.Type: GrantFiled: October 25, 2016Date of Patent: February 20, 2018Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Kuang Ming Chang, Lin Chen, Qihong Huang
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Patent number: 9846469Abstract: A fault tolerant power supply system includes at least one load switch circuit configured to connect, using a main switch, an input voltage to an output node of the load switch circuit when the load switch circuit is turned on and at least one power channel coupled to the load switch circuit to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the main switch of the load switch circuit, to determine that the current flowing through the main switch of the load switch circuit has exceeded a current limit threshold, and to disable the main switch of the load switch circuit and the low-side power switch of the power channel in response to the determination that the current flowing in the main switch has exceeded the current limit threshold.Type: GrantFiled: May 16, 2016Date of Patent: December 19, 2017Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee, Son Tran
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Patent number: 9705395Abstract: A fault tolerant power supply system includes at least one load switch configured to connect an input voltage to an output node of the load switch when the load switch is turned on and at least one power channel coupled to the load switch to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the low-side power switch, to determine that the current flowing through the low-side power switch has exceeded a current limit threshold, and to disable the low-side power switch and the load switch in response to the determination that the current flowing in the low-side power switch has exceeded the current limit threshold.Type: GrantFiled: July 7, 2015Date of Patent: July 11, 2017Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee
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Publication number: 20160259390Abstract: A fault tolerant power supply system includes at least one load switch circuit configured to connect, using a main switch, an input voltage to an output node of the load switch circuit when the load switch circuit is turned on and at least one power channel coupled to the load switch circuit to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the main switch of the load switch circuit, to determine that the current flowing through the main switch of the load switch circuit has exceeded a current limit threshold, and to disable the main switch of the load switch circuit and the low-side power switch of the power channel in response to the determination that the current flowing in the main switch has exceeded the current limit threshold.Type: ApplicationFiled: May 16, 2016Publication date: September 8, 2016Inventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee, Son Tran
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Patent number: 9367111Abstract: A fault tolerant power supply system includes at least one load switch circuit configured to connect, using a main switch, an input voltage to an output node of the load switch circuit when the load switch circuit is turned on and at least one power channel coupled to the load switch circuit to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the main switch of the load switch circuit, to determine that the current flowing through the main switch of the load switch circuit has exceeded a current limit threshold, and to disable the main switch of the load switch circuit and the low-side power switch of the power channel in response to the determination that the current flowing in the main switch has exceeded the current limit threshold.Type: GrantFiled: July 24, 2013Date of Patent: June 14, 2016Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee, Son Tran
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Publication number: 20160049876Abstract: A synchronous rectifier comprising a discrete switching device and a controller for controlling the discrete switching device both mounted on a common die pad and packaged in a single package. The packaging of the discrete switching device and the controller together in a single package provides shortest path of connection between the ports of the controller and the switching device, enabling the controller to accurately sense voltage across the switching device thereby avoiding the effect of parasitic inductances and enabling the controller to enable/disable the switching device at the precise time, resulting in improved power consumption and better efficiency.Type: ApplicationFiled: August 12, 2014Publication date: February 18, 2016Inventors: Gilbert Lee, James Park, Xiaotian Zhang, Benjamin Pun, Yu Ding, Alex Kim, Wayne F. Eng, Kuang Ming Chang, Xiaobin Wang
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Publication number: 20150311780Abstract: A fault tolerant power supply system includes at least one load switch configured to connect an input voltage to an output node of the load switch when the load switch is turned on and at least one power channel coupled to the load switch to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the low-side power switch, to determine that the current flowing through the low-side power switch has exceeded a current limit threshold, and to disable the low-side power switch and the load switch in response to the determination that the current flowing in the low-side power switch has exceeded the current limit threshold.Type: ApplicationFiled: July 7, 2015Publication date: October 29, 2015Inventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee
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Patent number: 9106075Abstract: A fault tolerant power supply system includes at least one load switch configured to connect an input voltage to an output node of the load switch when the load switch is turned on and at least one power channel coupled to the load switch to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the low-side power switch, to determine that the current flowing through the low-side power switch has exceeded a current limit threshold, and to disable the low-side power switch and the load switch in response to the determination that the current flowing in the low-side power switch has exceeded the current limit threshold.Type: GrantFiled: July 24, 2013Date of Patent: August 11, 2015Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee
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Patent number: 8890552Abstract: A flyback converter includes a transformer to convert an input voltage into an output voltage, a control circuit senses a primary current of the transformer to generate a current sense signal, and a sensing circuit is configured to sense a variation of the current sense signal between two time points for extracting the input voltage information therefrom.Type: GrantFiled: June 2, 2009Date of Patent: November 18, 2014Assignee: Richtek Technology Corp.Inventors: Pei-Lun Huang, Kuang-Ming Chang
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Publication number: 20140277802Abstract: A fault tolerant power supply system includes at least one load switch circuit configured to connect, using a main switch, an input voltage to an output node of the load switch circuit when the load switch circuit is turned on and at least one power channel coupled to the load switch circuit to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the main switch of the load switch circuit, to determine that the current flowing through the main switch of the load switch circuit has exceeded a current limit threshold, and to disable the main switch of the load switch circuit and the low-side power switch of the power channel in response to the determination that the current flowing in the main switch has exceeded the current limit threshold.Type: ApplicationFiled: July 24, 2013Publication date: September 18, 2014Applicant: Alpha and Omega Semiconductor IncorporatedInventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee, Son Tran
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Publication number: 20140268939Abstract: A fault tolerant power supply system includes at least one load switch configured to connect an input voltage to an output node of the load switch when the load switch is turned on and at least one power channel coupled to the load switch to receive the input voltage. The power channel is configured as a buck converter and includes at least a high-side power switch and a low-side power switch. The fault tolerant power supply system is configured to measure a current flowing through the low-side power switch, to determine that the current flowing through the low-side power switch has exceeded a current limit threshold, and to disable the low-side power switch and the load switch in response to the determination that the current flowing in the low-side power switch has exceeded the current limit threshold.Type: ApplicationFiled: July 24, 2013Publication date: September 18, 2014Applicant: Alpha and Omega Semiconductor IncorporatedInventors: Mark Tomas, Zhiye Zhang, Allen Chang, Kuang Ming Chang, Gilbert Lee
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Patent number: 8493047Abstract: A control circuit for a switching regulator implements constant on-time control scheme with synchronous rectification and applies dual control loops to improve light load efficiency and enhance transient response. In one embodiment, the control circuit includes a first control loop configured to control a one-shot timer to generate a control signal to turn on the main switch when the feedback voltage is below a first reference voltage and a minimum off-time duration has expired. The control circuit further includes a second control loop configured to control the one-shot timer to generate the control signal to turn on the main switch when the feedback voltage is below a second reference voltage and the minimum off-time duration has expired and a low-side current signal has a first state indicative of a light load condition at the output node.Type: GrantFiled: May 23, 2011Date of Patent: July 23, 2013Assignee: Alpha and Omega Semiconductor IncorporatedInventors: Zhiye Zhang, Kuang Ming Chang