Patents by Inventor Wan Tim Chan
Wan Tim Chan 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: 11245391Abstract: Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of ?100 V to +100 V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gm biasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.Type: GrantFiled: July 20, 2020Date of Patent: February 8, 2022Assignee: MICROCHIP TECHNOLOGY INC.Inventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan, Jimes Lei
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Publication number: 20210367500Abstract: Disclosed herein is a method. An output voltage level is sensed. Determining if a power source delivers power to a system. If the output voltage is higher than a designed voltage threshold (Vh), then the power source will stop delivery of power to a circuit. If the output voltage is lower than another voltage threshold (Vl), the power source transfers power to the system until the output voltage reaches the designed voltage threshold (Vh).Type: ApplicationFiled: May 19, 2020Publication date: November 25, 2021Inventors: Ka Wai Ho, Wan Tim Chan, Ngai Wa Wong, Chiu Sing Celement Tse
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Publication number: 20210175796Abstract: Disclosed herein is a fast voltage stabilizer wherein an actual voltage across a targeted electronic element is sensed. The actual voltage is compared with a reference voltage. A control signal is generated, wherein in response to the control signal, an external current path is provided to maintain current flow and stabilize the actual voltage through charging or discharging an input capacitor and a supply filtering capacitor. Under an arbitrary supply voltage variation, a fast dynamic response to regulate the voltage across the targeted electronic element is provided no matter what the operating mode of the entire electrical circuit is, including but not limited by constant current mode, constant output resistant mode and constant power mode.Type: ApplicationFiled: December 6, 2019Publication date: June 10, 2021Inventors: Ka Wai Ho, Chung Pui Tung, Po Wa Chow, Wing To Fan, Wan Tim Chan, Ke Wei Wang, Shu Hung Henry Chung, Chiu Sing Celement Tse
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Publication number: 20200350901Abstract: Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of ?100 V to +100 V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gm biasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.Type: ApplicationFiled: July 20, 2020Publication date: November 5, 2020Inventors: Isaac Ko, KA WAI HO, WAN TIM CHAN, JIMES LEI
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Patent number: 10756719Abstract: Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of ?100V to +100V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gm biasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.Type: GrantFiled: October 21, 2015Date of Patent: August 25, 2020Assignee: MICROCHIP TECHNOLOGY INC.Inventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan, Jimes Lei
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Patent number: 10637358Abstract: A current control circuit having a current regulation element, a first control circuit, and a second control circuit. The first control circuit is arranged to regulate, based on a reference current, a current flowing with respect to the current regulation element. The second control circuit is arranged to regulate, based on a reference voltage, a voltage across the current regulation element.Type: GrantFiled: December 18, 2017Date of Patent: April 28, 2020Assignee: Mosway Semiconductor LimitedInventors: Ka Wai Ho, Chung Pui Tung, Po Wa Chow, Wing To Fan, Wan Tim Chan, Shu Hung Henry Chung, Chiu Sing Tse
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Patent number: 10468869Abstract: An analog transmit/receive switch and voltage detection circuit that do not require depletion mode devices are provided. The switch may be configured to operate in a receive mode and a protection mode. The voltage detection circuit may be coupled to the switch and may be configured to measure a potential difference between two terminals of the switch. The switch and the voltage detection circuit may not include any depletion mode devices.Type: GrantFiled: March 17, 2017Date of Patent: November 5, 2019Assignee: Microchip Technology IncorporatedInventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan
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Patent number: 10469043Abstract: An ultrasound probe buffer is provided. The ultrasound probe buffer may include a high impedance amplifier having a common-source core stage with series-series local feedback. The high impedance amplifier may include a first MOSFET and a second MOSFET, wherein a source terminal of the first MOSFET is coupled to a source terminal of the second MOSFET.Type: GrantFiled: March 17, 2017Date of Patent: November 5, 2019Assignee: Microchip Technology IncorporatedInventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20190190389Abstract: A current control circuit having a current regulation element, a first control circuit, and a second control circuit. The first control circuit is arranged to regulate, based on a reference current, a current flowing with respect to the current regulation element. The second control circuit is arranged to regulate, based on a reference voltage, a voltage across the current regulation element.Type: ApplicationFiled: December 18, 2017Publication date: June 20, 2019Inventors: Ka Wai HO, Chung Pui TUNG, Po Wa CHOW, Wing To FAN, Wan Tim CHAN, Shu Hung Henry CHUNG, Chiu Sing TSE
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Patent number: 10171072Abstract: An improved analog switch for use in an ultrasound elastography probe is disclosed. The improved analog switch results in less heat dissipation compared to prior art analog switches.Type: GrantFiled: September 14, 2016Date of Patent: January 1, 2019Assignee: MICROCHIP TECHNOLOGY INC.Inventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20170279263Abstract: An analog transmit/receive switch and voltage detection circuit that do not require depletion mode devices are provided. The switch may be configured to operate in a receive mode and a protection mode. The voltage detection circuit may be coupled to the switch and may be configured to measure a potential difference between two terminals of the switch. The switch and the voltage detection circuit may not include any depletion mode devices.Type: ApplicationFiled: March 17, 2017Publication date: September 28, 2017Applicant: Microchip Technology IncorporatedInventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20170279423Abstract: An ultrasound probe buffer is provided. The ultrasound probe buffer may include a high impedance amplifier having a common-source core stage with series-series local feedback. The high impedance amplifier may include a first MOSFET and a second MOSFET, wherein a source terminal of the first MOSFET is coupled to a source terminal of the second MOSFET.Type: ApplicationFiled: March 17, 2017Publication date: September 28, 2017Applicant: Microchip Technology IncorporatedInventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20170104481Abstract: An improved analog switch for use in an ultrasound elastography probe is disclosed. The improved analog switch results in less heat dissipation compared to prior art analog switches.Type: ApplicationFiled: September 14, 2016Publication date: April 13, 2017Inventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20160191036Abstract: Described herein are multiple designs for an improved analog switch for use in transmitting high voltage signals without using high voltage power supplies for the switch. The analog switches are able to pass and block input signals in the approximate range of ?100V to +100V. The use of translinear loops and a bootstrap configuration results in a constant on-resistance of the symmetrical switches and matches the conductance of each analog switch to the transconductance of an NMOS transistor, which can be easily stabilized with a constant gm biasing scheme. In certain embodiments, a shunt termination (T-switch) configuration is used for better off-isolation, and each of the symmetrical switches has its own translinear loop and thus flexibility of on-resistance and termination voltage.Type: ApplicationFiled: October 21, 2015Publication date: June 30, 2016Inventors: Isaac Ko, Ka Wai Ho, Wan Tim Chan, Jimes Lei
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Patent number: 8937565Abstract: An impedance matching transmission circuit for a transducer has a transmission medium connected to the transducer. A transmitting circuit is connected to the transmission medium with the transmitting circuit terminating in a reference circuit element. The transmitting circuit comprises an analog to digital converter having an analog input connected to the reference circuit element, and having a digital output. A digital to analog converter receives the digital output and generates an analog output signal in response thereto. A driver circuit is connected to the transmission medium and receives the analog output signal and supplies a driver signal to the transmission medium.Type: GrantFiled: August 22, 2012Date of Patent: January 20, 2015Assignee: Supertex, Inc.Inventors: Isaac Terasuth Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20120313485Abstract: An impedance matching transmission circuit for a transducer has a transmission medium connected to the transducer. A transmitting circuit is connected to the transmission medium with the transmitting circuit terminating in a reference circuit element. The transmitting circuit comprises an analog to digital converter having an analog input connected to the reference circuit element, and having a digital output. A digital to analog converter receives the digital output and generates an analog output signal in response thereto. A driver circuit is connected to the transmission medium and receives the analog output signal and supplies a driver signal to the transmission medium.Type: ApplicationFiled: August 22, 2012Publication date: December 13, 2012Applicant: Supertex, Inc.Inventors: Isaac Terasuth KO, Ka Wai HO, Wan Tim CHAN
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Patent number: 8269656Abstract: An impedance matching transmission circuit for a transducer has a transmission medium connected to the transducer. A transmitting circuit is connected to the transmission medium with the transmitting circuit terminating in a reference circuit element. The transmitting circuit comprises an analog to digital converter having an analog input connected to the reference circuit element, and having a digital output. A digital to analog converter receives the digital output and generates an analog output signal in response thereto. A driver circuit is connected to the transmission medium and receives the analog output signal and supplies a driver signal to the transmission medium.Type: GrantFiled: May 24, 2010Date of Patent: September 18, 2012Assignee: Supertex, Inc.Inventors: Isaac Terasuth Ko, Ka Wai Ho, Wan Tim Chan
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Patent number: 8193839Abstract: A multi-level transmitter circuit with substantially constant output impedance has a capacitive transducer connected between a voltage input and ground. A first voltage path connects the voltage input to a first positive voltage source. The first voltage path is controlled by a first control signal. A second voltage path connects the voltage input to a second positive voltage source, less than the first positive voltage source. The second voltage path passes through a diode and is controlled by a second control signal. A third voltage path connects the voltage input to a third voltage source, less than ground, and is controlled by the second control signal. The impedance at the voltage input during the first control signal is substantially the same as the impedance at the voltage input during the second control signal.Type: GrantFiled: May 24, 2010Date of Patent: June 5, 2012Assignee: SuperTex, Inc.Inventors: Isaac Terasuth Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20110285457Abstract: A multi-level transmitter circuit with substantially constant output impedance has a capacitive transducer connected between a voltage input and ground. A first voltage path connects the voltage input to a first positive voltage source. The first voltage path is controlled by a first control signal. A second voltage path connects the voltage input to a second positive voltage source, less than the first positive voltage source. The second voltage path passes through a diode and is controlled by a second control signal. A third voltage path connects the voltage input to a third voltage source, less than ground, and is controlled by the second control signal. The impedance at the voltage input during the first control signal is substantially the same as the impedance at the voltage input during the second control signal.Type: ApplicationFiled: May 24, 2010Publication date: November 24, 2011Inventors: Isaac Terasuth Ko, Ka Wai Ho, Wan Tim Chan
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Publication number: 20110285561Abstract: An impedance matching transmission circuit for a transducer has a transmission medium connected to the transducer. A transmitting circuit is connected to the transmission medium with the transmitting circuit terminating in a reference circuit element. The transmitting circuit comprises an analog to digital converter having an analog input connected to the reference circuit element, and having a digital output. A digital to analog converter receives the digital output and generates an analog output signal in response thereto. A driver circuit is connected to the transmission medium and receives the analog output signal and supplies a driver signal to the transmission medium.Type: ApplicationFiled: May 24, 2010Publication date: November 24, 2011Inventors: Isaac Terasuth Ko, Ka Wai Ho, Wan Tim Chan