Patents by Inventor Sean S. Chen
Sean S. 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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Patent number: 10054647Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for fault detection in a power control system. In one aspect, a method includes measuring a plurality of values of a feedback voltage from a power control system over a period of time; determining a rate of feedback voltage change based on the measured values of the feedback voltage and a duration of the period of time; determining, with a controller, that the determined rate of feedback voltage change is smaller than a threshold rate of change; and in response to determining that the determined rate of feedback voltage change is smaller than the threshold rate of change, transmitting a fault indication signal to the power control system.Type: GrantFiled: September 15, 2014Date of Patent: August 21, 2018Assignee: Atmel CorporationInventor: Sean S. Chen
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Patent number: 9706610Abstract: A circuit for driving light emitting elements, such as LEDs, includes a first transistor having a source coupled to ground through a first resistive element, and a second transistor having a gate electrically coupled to a gate of the first transistor, a source electrically coupled to ground, and a drain for electrical connection to a first group of light emitting elements. The circuit also includes circuitry to provide a predetermined voltage at the source of the first transistor, circuitry to compensate for a difference in respective gate-source voltages of the first and second transistors, and circuitry to compensate for a difference in respective drain-source voltages of the first and second transistors. In some implementations, the circuit can achieve relatively low power consumption.Type: GrantFiled: October 18, 2011Date of Patent: July 11, 2017Assignee: Atmel CorporationInventors: Sean S. Chen, Wenbo Liang
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Patent number: 9318959Abstract: A controller circuit for the control of a power converter is disclosed. An example controller circuit generates a waveform that drives a switch that controls the power converter. The controller circuit includes a divider module that generates a modification factor based on a ratio of the two input signals of the module. The circuit includes a module that generates a first waveform configured for a critical conducting mode of operation of a power converter and an on-time adjuster module that modifies the first waveform based on the modification factor and generates a second waveform. The second waveform is delivered to the switch. An example modification factor is the ratio of the output voltage to the rectified input voltage of the power converter.Type: GrantFiled: January 31, 2013Date of Patent: April 19, 2016Assignee: Atmel CorporationInventors: Hong Zhang, Sean S. Chen, Dilip Sangam
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Publication number: 20160077162Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for fault detection in a power control system. In one aspect, a method includes measuring a plurality of values of a feedback voltage from a power control system over a period of time; determining a rate of feedback voltage change based on the measured values of the feedback voltage and a duration of the period of time; determining, with a controller, that the determined rate of feedback voltage change is smaller than a threshold rate of change; and in response to determining that the determined rate of feedback voltage change is smaller than the threshold rate of change, transmitting a fault indication signal to the power control system.Type: ApplicationFiled: September 15, 2014Publication date: March 17, 2016Inventor: Sean S. Chen
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Patent number: 9288852Abstract: A circuit for driving light emitting elements, such as LEDs, includes a first transistor having a source coupled to ground through a first resistive element, and a second transistor having a gate electrically coupled to a gate of the first transistor, a source electrically coupled to ground, and a drain for electrical connection to a first group of light emitting elements. The circuit also includes circuitry to provide a predetermined voltage at the source of the first transistor, circuitry to compensate for a difference in respective gate-source voltages of the first and second transistors, and circuitry to compensate for a difference in respective drain-source voltages of the first and second transistors. In some implementations, the circuit can achieve relatively low power consumption.Type: GrantFiled: March 7, 2012Date of Patent: March 15, 2016Assignee: Atmel CorporationInventors: Sean S. Chen, Wenbo Liang
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Patent number: 9195249Abstract: An adaptive phase-lead compensation (zero) circuit is disclosed that can be added to a circuit (e.g., a CMOS-based LDO) to ease the compensation and increase the phase margin of the circuit. By using the disclosed adaptive phase-lead compensation circuit, an adjustable resistance can be connected to any nodes in the compensated circuit rather than just to the voltage source (VDD) or ground (GND), allowing the Miller Effect to be used via a Miller capacitor.Type: GrantFiled: December 20, 2011Date of Patent: November 24, 2015Assignee: Atmel CorporationInventors: Sean S. Chen, Liwei Liu, Yongliang Wang
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Patent number: 9088219Abstract: A dual-mode circuit for the control of an AC/DC power converter is disclosed. An example dual-mode controller circuit generates a waveform that drives a switch on or off and controls the power converter. The controller circuit in addition to power factor correction (PFC) circuitry includes a critical conducting mode (CrM) module as well as a discontinuous conducting mode (DCM) module configured to generate waveforms adapted for CrM and DCM operation of a power converter. The circuit includes a node for receiving a feedback signal of a voltage or a current. Based on the received signal, one of the modules is selected at a time to supply the waveform at the output of the dual-mode controller. An example of the output waveform is a series of pulses that are configured to drive the switch that controls the transfer of power between input and output of the power converter.Type: GrantFiled: November 30, 2012Date of Patent: July 21, 2015Assignee: Atmel CorporationInventors: Hong Zhang, Sean S. Chen, Dilip Sangam
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Patent number: 9013110Abstract: In one novel aspect, driving a string of light emitting elements, such as LEDs, includes applying a drive signal to circuitry that regulates a voltage appearing at a source of a transistor whose drain is coupled to one end of the string of light emitting elements and whose source is coupled to ground through a resistive element. Sequencing of the drive signal and a voltage supply signal for the light emitting elements is controlled such that the voltage supply signal is not increased above a predetermined allowable voltage for the transistor until the transistor is turned on, and such that the supply voltage is not decreased below the allowable voltage for the transistor until the transistor is turned off.Type: GrantFiled: November 30, 2011Date of Patent: April 21, 2015Assignee: Atmel CorporationInventors: Sean S. Chen, Jeff Kotowski, Timothy James Herklots
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Patent number: 8952623Abstract: The disclosed multi-channel driver equalizer circuit matches currents in multiple strings of illumination devices at low current levels by using an analog equalizer to sequentially couple the output of a reference amplifier in series with each current source amplifier in a current limit loop of the driver equalizer circuit to correct the offsets of the current source amplifiers, resulting in the matching of string currents on average.Type: GrantFiled: October 25, 2011Date of Patent: February 10, 2015Assignee: Atmel CorporationInventors: Sean S. Chen, Jeff Kotowski, Timothy James Herklots
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Publication number: 20140211518Abstract: A controller circuit for the control of a power converter is disclosed. An example controller circuit generates a waveform that drives a switch that controls the power converter. The controller circuit includes a divider module that generates a modification factor based on a ratio of the two input signals of the module. The circuit includes a module that generates a first waveform configured for a critical conducting mode of operation of a power converter and an on-time adjuster module that modifies the first waveform based on the modification factor and generates a second waveform. The second waveform is delivered to the switch. An example modification factor is the ratio of the output voltage to the rectified input voltage of the power converter.Type: ApplicationFiled: January 31, 2013Publication date: July 31, 2014Applicant: ATMEL CorporationInventors: Hong Zhang, Sean S. Chen, Dilip Sangam
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Publication number: 20140160802Abstract: A fault protection and correction circuit for the control of a power converter is disclosed. An example circuit generates a waveform that drives a switch on or off and controls the power converter. The controller circuit in addition to power factor correction (PFC) circuitry includes a first and a second shut down mode modules, both of them cause the switching to stop. The circuit includes a module for receiving fault events. When a fault occurs, the controller enters the second shut down mode. The controller stays in the second shut down mode if the required current for this mode can be provided by the outside circuitry. Otherwise, the controller enters the first shut down mode that requires less current and subsequently restarts the controller. By modifying the outside circuitry the controller can respond differently to fault events.Type: ApplicationFiled: December 7, 2012Publication date: June 12, 2014Applicant: Atmel CorporationInventors: Hong Zhang, Sean S. Chen, Dilip Sangam, Wenbo Liang
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Publication number: 20140153291Abstract: A dual-mode circuit for the control of an AC/DC power converter is disclosed. An example dual-mode controller circuit generates a waveform that drives a switch on or off and controls the power converter. The controller circuit in addition to power factor correction (PFC) circuitry includes a critical conducting mode (CrM) module as well as a discontinuous conducting mode (DCM) module configured to generate waveforms adapted for CrM and DCM operation of a power converter. The circuit includes a node for receiving a feedback signal of a voltage or a current. Based on the received signal, one of the modules is selected at a time to supply the waveform at the output of the dual-mode controller. An example of the output waveform is a series of pulses that are configured to drive the switch that controls the transfer of power between input and output of the power converter.Type: ApplicationFiled: November 30, 2012Publication date: June 5, 2014Applicant: ATMEL CorporationInventors: Hong Zhang, Sean S. Chen, Dilip Sangam
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Publication number: 20130154593Abstract: An adaptive phase-lead compensation (zero) circuit is disclosed that can be added to a circuit (e.g., a CMOS-based LDO) to ease the compensation and increase the phase margin of the circuit. By using the disclosed adaptive phase-lead compensation circuit, an adjustable resistance can be connected to any nodes in the compensated circuit rather than just to the voltage source (VDD) or ground (GND), allowing the Miller Effect to be used via a Miller capacitor.Type: ApplicationFiled: December 20, 2011Publication date: June 20, 2013Applicant: ATMEL CORPORATIONInventors: Sean S. Chen, Liwei Liu, Yongliang Wang
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Publication number: 20130134889Abstract: In one novel aspect, driving a string of light emitting elements, such as LEDs, includes applying a drive signal to circuitry that regulates a voltage appearing at a source of a transistor whose drain is coupled to one end of the string of light emitting elements and whose source is coupled to ground through a resistive element. Sequencing of the drive signal and a voltage supply signal for the light emitting elements is controlled such that the voltage supply signal is not increased above a predetermined allowable voltage for the transistor until the transistor is turned on, and such that the supply voltage is not decreased below the allowable voltage for the transistor until the transistor is turned off.Type: ApplicationFiled: November 30, 2011Publication date: May 30, 2013Applicant: ATMEL CORPORATIONInventors: Sean S. Chen, Jeff Kotowski, Timothy James Herklots
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Publication number: 20130099697Abstract: The disclosed multi-channel driver equalizer circuit matches currents in multiple strings of illumination devices at low current levels by using an analog equalizer to sequentially couple the output of a reference amplifier in series with each current source amplifier in a current limit loop of the driver equalizer circuit to correct the offsets of the current source amplifiers, resulting in the matching of string currents on average.Type: ApplicationFiled: October 25, 2011Publication date: April 25, 2013Applicant: ATMEL CORPORATIONInventors: Sean S. Chen, Jeff Kotowski, Timothy James Herklots
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Publication number: 20130093338Abstract: A circuit for driving light emitting elements, such as LEDs, includes a first transistor having a source coupled to ground through a first resistive element, and a second transistor having a gate electrically coupled to a gate of the first transistor, a source electrically coupled to ground, and a drain for electrical connection to a first group of light emitting elements. The circuit also includes circuitry to provide a predetermined voltage at the source of the first transistor, circuitry to compensate for a difference in respective gate-source voltages of the first and second transistors, and circuitry to compensate for a difference in respective drain-source voltages of the first and second transistors. In some implementations, the circuit can achieve relatively low power consumption.Type: ApplicationFiled: October 18, 2011Publication date: April 18, 2013Applicant: ATMEL CORPORATIONInventors: Sean S. Chen, Wenbo Liang
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Publication number: 20130093339Abstract: A circuit for driving light emitting elements, such as LEDs, includes .a first transistor having a source coupled to ground through a first resistive element, and a second transistor having a gate electrically coupled to a gate of the first transistor, a source electrically coupled to ground, and a drain for electrical connection to a first group of light emitting elements. The circuit also includes circuitry to provide a predetermined voltage at the source of the first transistor, circuitry to compensate for a difference in respective gate-source voltages of the first and second transistors, and circuitry to compensate for a difference in respective drain-source voltages of the first and second. transistors. In some implementations, the circuit can achieve relatively low power consumption.Type: ApplicationFiled: March 7, 2012Publication date: April 18, 2013Applicant: ATMEL CORPORATIONInventors: Sean S. Chen, Wenbo Liang
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Patent number: 7400187Abstract: The present invention relates to a low impedance band-gap voltage reference circuit which comprises a band-gap reference circuit, a buffer circuit to reduce the impedance and related noise associated with band-gap references electronically coupled with the band-gap voltage reference circuit and a voltage pull-up device electronically coupled with both the band-gap reference circuit and the buffer circuit. The voltage pull-up device acts to reduce the supply voltage required to maintain a stable, low Z band-gap reference voltage.Type: GrantFiled: October 2, 2001Date of Patent: July 15, 2008Assignee: National Semiconductor CorporationInventor: Sean S. Chen
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Patent number: 6914494Abstract: A low current oscillator circuit comprising a comparator for driving an output signal. A first capacitor chain is coupled to the comparator. The first capacitor chain is configured for setting a first input voltage of the comparator. A second capacitor chain is also coupled to the comparator. The second capacitor chain is configured for setting a second input voltage of the comparator, wherein the first capacitor chain and the second capacitor chain determine a first voltage level and a second voltage level of oscillation of the comparator. The first capacitor chain and the second capacitor chain are free of DC current flow.Type: GrantFiled: August 26, 2003Date of Patent: July 5, 2005Assignee: National Semiconductor CorporationInventor: Sean S. Chen
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Patent number: 6819164Abstract: A circuit is arranged to enable bi-directional trimming of a reference voltage. A trim current is generated by mirroring a bias current using one or more selectable current source circuits. The selectable current source circuits may each contain transistors that are sized differently from corresponding transistors of the other selectable current source circuits. The sizing may be arranged in a binary chain such that a range of currents may be generated for the trim current while allowing for selection of the level of adjustment for the reference voltage. The current selected for the trim current depends on which of the selectable current sources is enabled. The node corresponding to the trim current is selectively coupled to a load to either increase the voltage across the load or decrease the voltage across the load, providing bi-directional trimming of the reference voltage measured across the load.Type: GrantFiled: October 17, 2002Date of Patent: November 16, 2004Assignee: National Semiconductor CorporationInventor: Sean S. Chen