Patents by Inventor Keming Chen
Keming Chen 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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Publication number: 20090243934Abstract: Instead of normalizing time reference of independent spatially-located clocks using a reference tag transmission from known location, the present invention uses an interarrival time interval between a pulse pair of UWB pulses as a timing metric. Thus, a method of synchronizing spatially-located clocks or normalizing time indications thereof comprises transmitting a UWB pulse pair, determining at first and second monitoring stations a respective count value indicative of a locally measured time interval between received pulse pairs, determining a ratio between clock counts of first and second monitoring stations, and utilizing the ratio to determine clock skew, e.g., a timing correction to be applied to respective local clocks of the monitoring stations.Type: ApplicationFiled: June 15, 2009Publication date: October 1, 2009Inventors: Aitan Ameti, Keming Chen, Robert J. Fontana, Edward A. Richley, Belinda Turner
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Patent number: 7586760Abstract: A DC-to-DC converter and associated methods are provided for controlling the discharge of snubber capacitances during a light/no load buck mode of operation. An operating method for a DC-to-DC converter detects conditions corresponding to a light/no load buck mode of operation, and, in response to the detection of that mode, controls the states of a first switch, a second switch, a first switched diode element, a second switched diode element, a third switched diode element, and a fourth switched diode element to facilitate discharging of a first capacitance element and a second capacitance element through a secondary winding of a transformer.Type: GrantFiled: December 18, 2007Date of Patent: September 8, 2009Assignee: GM Global Technology Operations, Inc.Inventor: Keming Chen
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Publication number: 20090161389Abstract: A method and apparatus for precharging a DC to DC power converter system is provided. The system includes a boost circuit for generating a boosted output voltage from an input voltage. The input voltage is monitored. A predetermined current limit is compared to a current in the boost circuit, and the current limited is increased when the input voltage is greater than a predetermined value.Type: ApplicationFiled: December 19, 2007Publication date: June 25, 2009Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventors: KEMING CHEN, DOUGLAS S. CARLSON, SUNG CHUNG
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Publication number: 20090153284Abstract: A vehicular power converter includes switches and first and second inductive components. The first and second inductive components have substantially adjacent portions and are coupled to the plurality of switches such that when current flows from the plurality of switches and through the first and second inductive components, flux generated by the current flowing through the adjacent portions of the first and second inductive components and located between the adjacent portions is oriented in substantially opposite directions.Type: ApplicationFiled: December 17, 2007Publication date: June 18, 2009Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventor: KEMING CHEN
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Publication number: 20090154205Abstract: A DC-to-DC converter and associated methods are provided for controlling the discharge of snubber capacitances during a light/no load buck mode of operation. An operating method for a DC-to-DC converter detects conditions corresponding to a light/no load buck mode of operation, and, in response to the detection of that mode, controls the states of a first switch, a second switch, a first switched diode element, a second switched diode element, a third switched diode element, and a fourth switched diode element to facilitate discharging of a first capacitance element and a second capacitance element through a secondary winding of a transformer.Type: ApplicationFiled: December 18, 2007Publication date: June 18, 2009Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.Inventor: KEMING CHEN
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Patent number: 7492316Abstract: Instead of normalizing time reference of independent spatially-located clocks using a reference tag transmission from known location, the present invention uses an interarrival time interval between a pulse pair of UWB pulses as a timing metric. Thus, a method of synchronizing spatially-located clock or normalizing time indications thereof comprises transmitting a UWB pulse pair, determining at first and second monitoring stations a respective count value indicative of a locally measured time interval between received pulse pairs, determining a ratio between clock counts of first and second monitoring stations, and utilizing the ratio to determine clock skew, e.g., a timing correction to be applied to respective local clocks of the monitoring stations.Type: GrantFiled: July 6, 2006Date of Patent: February 17, 2009Assignee: Multispectral Solutions, Inc.Inventors: Aitan Ameti, Keming Chen, Robert J. Fontana, Edward A. Richley, Belinda Turner
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Publication number: 20080284387Abstract: A method of operating an isolated bi-directional dc/dc converter to provide voltage regulation at a no-load condition over a wide voltage range and also provide overshoot protection for the boost mode main switching transistors uses new boost mode drive waveforms. The new waveforms drive switches S2 and S4 to be turned off during boost mode and only S1 and S3 are switched to provide reverse energy flow at no-load. In boost mode, C1 and C2 provide overshoot protection caused by leakage inductance of the isolation transformer when boost mode drive transistors turn off during forward energy flow and provide stored energy for reverse energy flow during reverse energy flow periods used for voltage regulation in the boost mode. In buck mode, C1 and C2 provide soft switching for buck mode main switching transistors S2 and S4.Type: ApplicationFiled: May 14, 2007Publication date: November 20, 2008Inventors: KEMING CHEN, Steven E. Schulz
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Patent number: 7393236Abstract: An electrical system as described herein is suitable for use in an electric or hybrid vehicle. The electrical system includes electrical devices, such as power transistors, coupled to an electrically and thermally conductive bus bar. The respective nodes of the electrical devices are coupled to the bus bar such that the bus bar carries a combined signal generated by the electrical devices. The bus bar is also thermally coupled to a conduction heat transfer system, such as a liquid cooled cold plate. Thus, the bus bar functions as both an electrical conduit and a conduction-based heat sink for the electrical system.Type: GrantFiled: September 2, 2005Date of Patent: July 1, 2008Assignee: GM Global Technology Operations, Inc.Inventors: Alex Thompson, Mark D. Korich, Mark L Selogie, Keming Chen
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Patent number: 7362077Abstract: A boost control module operates semiconductor switches of a boost converter circuit in an avalanche mode to precharge a boost output capacitor. The boost control module comprises a switching module that complementarily transitions a first semiconductor switch and a second semiconductor switch between ON and OFF states when a current does not exceed a maximum current threshold. The switching module transitions the first semiconductor switch and the second semiconductor switch to the OFF state when the current exceeds the maximum current threshold. The switching module maintains the first semiconductor switch and the second semiconductor switch in the OFF state until at least one of the inductor current is less than or equal to a minimum current threshold.Type: GrantFiled: August 2, 2005Date of Patent: April 22, 2008Assignee: GM Global Technology Operations, Inc.Inventor: Keming Chen
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Patent number: 7345861Abstract: A capacitor circuit with surge protection that is selectively connected between a voltage source and a device includes a first capacitance element has one end that communicates with a first terminal of the voltage source. A first transistor has a first terminal that communicates with an opposite end of the first capacitance element and a second terminal that communicates with a second terminal of the voltage source. A control terminal of the first transistor communicates with a capacitor enable signal that provides a controlled turn-on to limit current surge and turns off the first transistor when voltage surge is detected.Type: GrantFiled: August 23, 2005Date of Patent: March 18, 2008Assignee: GM Global Technology Operations, Inc.Inventor: Keming Chen
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Patent number: 7312653Abstract: A reverse polarity protected system comprises a voltage source that includes positive and negative terminals. A polarity-sensitive device has a first terminal that communicates with the positive terminal of the voltage source, and that includes a second terminal. A low-resistance switch communicates with the first and second terminals of the voltage source, and communicates with the second terminal of the polarity-sensitive device. The low-resistance switch assumes a conducting state between the second terminal of the polarity-sensitive device and the negative terminal of the voltage source when a first voltage at the positive terminal of the voltage source minus a second voltage at the negative terminal of the voltage source is greater than a threshold voltage. Otherwise, the low-resistance switch assumes a non-conducting state.Type: GrantFiled: March 10, 2005Date of Patent: December 25, 2007Assignee: GM Global Technology Operations, Inc.Inventors: Keming Chen, David Tang
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Publication number: 20070129010Abstract: A method and system for controlling an output signal power level of a wireless transmitter can be created by detecting the signal power level of the transmitter with a detector, selectively attenuating the output signal power level with an attenuator having variable attenuation levels, and monitoring the output signal power level and comparing the output signal power level, as determined by the detector, to a predetermined threshold with a processor. The processor preferably controls the attenuator in accordance with the comparison of the output signal power level and the predetermined threshold.Type: ApplicationFiled: February 9, 2007Publication date: June 7, 2007Applicant: GENERAL INSTRUMENT CORPORATIONInventor: Keming Chen
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Publication number: 20070096705Abstract: A current mode control circuit uses a current comparing module to control a switching signal according to one of a plurality of current feedback signals. The current mode circuit comprises a voltage control module that generates an output voltage according to an input voltage and the switching control signal, and that generates the plurality of current feedback signals. The current comparing module outputs a control current signal that is indicative of a greater one of the plurality of current feedback signals. A current mode control module receives the control current signal and generates the switching control signal according to the control current signal.Type: ApplicationFiled: October 31, 2005Publication date: May 3, 2007Inventor: Keming Chen
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Publication number: 20070070664Abstract: A current sensing circuit that determines an output current of a bi-directional converter circuit comprises a current transformer that receives a first current signal and that outputs a second current signal. The first current signal is indicative of the output current and flows in one of a first direction and/or a second direction. The second current signal is indicative of the first current signal. A current sensing module receives the second current signal and has a first state and a second state. A converter control module simultaneously transitions the first current signal from the first direction to the second direction and transitions the current sensing module from the first state to the second state. The converter control module transitions the current sensing module to the first state after a resetting period.Type: ApplicationFiled: September 27, 2005Publication date: March 29, 2007Inventor: Keming Chen
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Publication number: 20070053163Abstract: An electrical system as described herein is suitable for use in an electric or hybrid vehicle. The electrical system includes electrical devices, such as power transistors, coupled to an electrically and thermally conductive bus bar. The respective nodes of the electrical devices are coupled to the bus bar such that the bus bar carries a combined signal generated by the electrical devices. The bus bar is also thermally coupled to a conduction heat transfer system, such as a liquid cooled cold plate. Thus, the bus bar functions as both an electrical conduit and a conduction-based heat sink for the electrical system.Type: ApplicationFiled: September 2, 2005Publication date: March 8, 2007Inventors: Alex Thompson, Mark Korich, Mark Selogie, Keming Chen
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Publication number: 20070047171Abstract: A capacitor circuit with surge protection that is selectively connected between a voltage source and a device comprises a first capacitance element has one end that communicates with a first terminal of the voltage source. A first transistor has a first terminal that communicates with an opposite end of the first capacitance element and a second terminal that communicates with a second terminal of the voltage source. A control terminal of the first transistor communicates with a capacitor enable signal that provides a controlled turn-on to limit current surge and turns off the first transistor when voltage surge is detected.Type: ApplicationFiled: August 23, 2005Publication date: March 1, 2007Inventor: Keming Chen
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Publication number: 20070029982Abstract: A boost control module operates semiconductor switches of a boost converter circuit in an avalanche mode to precharge a boost output capacitor. The boost control module comprises a switching module that complementarily transitions a first semiconductor switch and a second semiconductor switch between ON and OFF states when a current does not exceed a maximum current threshold. The switching module transitions the first semiconductor switch and the second semiconductor switch to the OFF state when the current exceeds the maximum current threshold. The switching module maintains the first semiconductor switch and the second semiconductor switch in the OFF state until at least one of the inductor current is less than or equal to a minimum current threshold.Type: ApplicationFiled: August 2, 2005Publication date: February 8, 2007Inventor: Keming Chen
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Patent number: 7116012Abstract: A power conversion circuit includes a current section, a transformer, and a voltage section. The current section includes inductors configured to produce a boosted output voltage from a voltage sourse when then current section is operating in a forward direction. The transformer includes a primary winding electrically coupled to the secondary winding and configured to drive a load. The voltage section includes a pluralaty of balancing switchtes configured to actively driven to provide a DC voltage to the load. The balancing switches balance energy between the current section and the voltage section when the power conversion circuit is the load and operating in the forward direction.Type: GrantFiled: July 30, 2003Date of Patent: October 3, 2006Assignee: General Motors CorporationInventors: Lateef A. Kajouke, Keming A. Chen, James F. Lazar
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Publication number: 20060202746Abstract: A reverse polarity protected system comprises a voltage source that includes positive and negative terminals. A polarity-sensitive device has a first terminal that communicates with the positive terminal of the voltage source, and that includes a second terminal. A low-resistance switch communicates with the first and second terminals of the voltage source, and communicates with the second terminal of the polarity-sensitive device. The low-resistance switch assumes a conducting state between the second terminal of the polarity-sensitive device and the negative terminal of the voltage source when a first voltage at the positive terminal of the voltage source minus a second voltage at the negative terminal of the voltage source is greater than a threshold voltage. Otherwise, the low-resistance switch assumes a non-conducting state.Type: ApplicationFiled: March 10, 2005Publication date: September 14, 2006Inventors: Keming Chen, David Tang
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Patent number: 7106605Abstract: A DC-DC converter comprises an input circuit that stores inductive energy that includes a first switch that releases the stored inductive energy. A transformer includes a primary winding that communicates with the input circuit and a secondary winding. An output circuit communicates with the secondary winding and that includes first and second output conductors and a first diode that communicates with one end of the secondary winding and the first output conductor. A second diode communicates with one end of the secondary winding and the second output conductor. A third diode communicates with an opposite end of the secondary winding and the first output conductor. A fourth diode communicates with an opposite end of the secondary winding and the second output conductor. A first capacitor is connected in parallel to the third diode. A second capacitor is connected in parallel to the fourth diode.Type: GrantFiled: June 30, 2004Date of Patent: September 12, 2006Assignee: General Motors CorporationInventors: Keming Chen, Lateef A. Kajouke, James F. Lazar