Patents by Inventor Wanfeng Zhang
Wanfeng Zhang 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: 20150078047Abstract: Aspects of the disclosure provide a circuit that includes a detector and a controller. The detector is configured to detect a firing start by a triode for alternating current (TRIAC) in a power supply. The controller is configured to control a switch in connection with a magnetic component in response to the firing start to shape a profile of a current pulled from the power supply to satisfy a latch current requirement and a hold current requirement of the TRIAC.Type: ApplicationFiled: November 21, 2014Publication date: March 19, 2015Applicant: MARVELL WORLD TRADE LTDInventors: Sehat SUTARDJA, Pantas Sutardja, Wanfeng Zhang
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Publication number: 20150077090Abstract: A first filter outputs a first signal in response to receiving an input signal. The first signal has a first state in response to the input signal reaching a first threshold voltage on a leading edge of the input signal, and a second state in response to the input signal reaching the first threshold voltage on a trailing edge of the input signal. A second filter outputs a second signal in response to receiving the input signal. The second signal has the first state in response to the input signal reaching a second threshold voltage on the leading edge of the input signal, and the second state in response to the input signal reaching the second threshold voltage on the trailing edge of the input signal. A detection circuit determines, based on times when the first and second thresholds are reached, whether the input signal is received from a triac.Type: ApplicationFiled: November 20, 2014Publication date: March 19, 2015Inventors: Jinho Choi, Hao Peng, Wanfeng Zhang, Tuyen Doan
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Patent number: 8957602Abstract: New and useful methods and systems for providing lighting control are disclosed. For example, in an embodiment a lighting system includes one or more first solid state lights having a first aesthetic color, one or more second solid state lights having a second aesthetic color, the second aesthetic color having an appreciably longer wavelength than the first aesthetic color, and an amplitude correlation circuit configured to control a ratio of first light produced by the one or more first solid state lights to second light produced by the one or more second solid state lights as a function of a received dimming control signal.Type: GrantFiled: July 13, 2012Date of Patent: February 17, 2015Assignee: Marvell World Trade Ltd.Inventors: Wanfeng Zhang, Pantas Sutardja
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Patent number: 8947895Abstract: A system including a switch configured to supply power to a load. A first comparator is configured to compare a first current through the switch to a first threshold. A second comparator is configured to compare the first current through the switch to a second threshold. The second threshold is greater than the first threshold. A current control module is configured to turn off the switch (i) for a first duration in response to the first current through the switch being greater than or equal to the first threshold and (ii) for a second duration in response to the first current through the switch being greater than or equal to the second threshold. The current control module is configured to adjust the second duration based on a difference between an estimated current through the load and a desired current through the load.Type: GrantFiled: February 24, 2012Date of Patent: February 3, 2015Assignee: Marvell World Trade Ltd.Inventors: Jinho Choi, Hao Peng, Wanfeng Zhang, Tuyen Doan
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Patent number: 8937435Abstract: Aspects of the disclosure provide a circuit that includes a first circuit, a second circuit and a bridge circuit. The first circuit is coupled to a magnetic component to receive electric energy transferred via the magnetic component and thus configured to store the electric energy and generate a supply voltage. The second circuit is also coupled to the magnetic component. The second circuit is switchable and is configured to deplete a portion of the electric energy when the second circuit is switched on. The bridge circuit is coupled between the first circuit and the second circuit to provide a charge flow path when the second circuit is switched off.Type: GrantFiled: August 27, 2013Date of Patent: January 20, 2015Assignee: Marvell International Ltd.Inventors: Sehat Sutardja, Wanfeng Zhang
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Publication number: 20150015158Abstract: A system configured to provide current to power a solid-state light emitting diode in accordance with a dimming level, wherein the dimming level corresponds to an amount of light provided from the solid-state light emitting diode. The system includes a transformer and a switch. The transformer includes a coil. The transformer is configured to receive a first current. The coil is configured to, based on the first current, output a second current to power the solid-state light emitting diode. The switch is configured to, based on a dimming level that corresponds to the amount of light provided from the solid-state light emitting diode of the system, bleed a portion of the second current out of the coil to a ground reference in order to divert the portion of the second current from being supplied to the solid-state light emitting diode.Type: ApplicationFiled: September 29, 2014Publication date: January 15, 2015Inventors: Sehat Sutardja, Pantas Sutardja, Wanfeng Zhang, Jinho Choi
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Publication number: 20140347894Abstract: Aspects of the disclosure provide a circuit that includes a detector and a controller. The detector is configured to detect a firing start by a triode for alternating current (TRIAC) in a power supply. The controller is configured to control a switch in connection with a magnetic component in response to the firing start to shape a profile of a current pulled from the power supply to satisfy a latch current requirement and a hold current requirement of the TRIAC.Type: ApplicationFiled: May 22, 2014Publication date: November 27, 2014Applicant: MARVELL WORLD TRADE LTDInventors: Sehat Sutardja, Pantas Sutardja, Wanfeng Zhang
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Patent number: 8896288Abstract: Methods, circuits, and systems for determining the presence of a chopped input signal are disclosed. A digital signal generator can produce multiple digital signals when an alternating current (AC) signal input reaches multiple threshold voltages. The times at which the threshold voltages are reached can be determined by looking at the times at which the digital signals go high and low. The differences between the times at which the digital signals go high and low are used to determine if the AC signal input is a leading or trailing edge chopped signal. The AC input signal is a leading edge chopped signal when the difference between the times at which the digital signals go high is less than a predetermined time threshold, and is a trailing edge chopped signal when the difference between the times at which the digital signals go low is less than a predetermined time threshold.Type: GrantFiled: February 16, 2012Date of Patent: November 25, 2014Assignee: Marvell World Trade Ltd.Inventors: Jinho Choi, Hao Peng, Wanfeng Zhang, Tuyen Doan
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Publication number: 20140333216Abstract: An apparatus includes a first LED driver configured to control a first string of LEDs, a second LED driver configured to control a second string of LEDs, a third LED driver configured to control a third string of LEDs, and a control circuit configured to receive a control signal and to control the first, second, and third LED drivers so that the first, second, and third strings of LEDs cooperate in producing light according to the control signal and a color curve.Type: ApplicationFiled: May 7, 2014Publication date: November 13, 2014Applicant: Marvell World Trade Ltd.Inventors: Wanfeng ZHANG, Pantas SUTARDJA
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Publication number: 20140327372Abstract: Aspects of the disclosure provide a method for driving dimmable load. The method includes detecting a dimming characteristic in an energy source from which a load draws a first energy according to the dimming characteristic. The dimming characteristic requires a second energy in addition to the first energy to be drawn from the energy source to sustain an operation of the energy source. The method further includes biasing a switch to consume the second energy. The second energy and the first energy are drawn from the energy source to sustain the operation of the energy source.Type: ApplicationFiled: April 8, 2014Publication date: November 6, 2014Applicant: Marvell World Trade Ltd.Inventors: Wanfeng Zhang, Daniel Reed, Jinho Choi, Pantas Sutardja
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Patent number: 8847517Abstract: A system includes a transformer. The transformer includes a first coil and a second coil. The first coil is configured to receive a first voltage based on an output of a switching circuit. The second coil is configured to generate a first current based on the first voltage to power a solid-state load. The system also includes a third coil. The third coil is configured to generate a second voltage based on the first voltage.Type: GrantFiled: June 18, 2012Date of Patent: September 30, 2014Assignee: Marvell World Trade Ltd.Inventors: Sehat Sutardja, Pantas Sutardja, Wanfeng Zhang, Jinho Choi
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Publication number: 20140284635Abstract: An integrated circuit including a die of the integrated circuit, the die including an insulating layer, light emitting diodes, a semiconductor layer, and a control module. The insulating layer includes a first side and a second side. The second side is opposite to the first side. The light emitting diodes are arranged on the first side of the insulating layer. The semiconductor layer is arranged adjacent to the second side of the insulating layer. The light emitting diodes are connected to the semiconductor layer using connections from the first side of the insulating layer to the second side of the insulating layer. The control module is arranged on the semiconductor layer. The control module is configured to output pulse width modulated pulses to the light emitting diodes via the connections.Type: ApplicationFiled: June 9, 2014Publication date: September 25, 2014Inventors: Wanfeng Zhang, Albert Wu
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Publication number: 20140285169Abstract: A controller for a power conversion circuit that includes an inductor, a diode, and a switch. The controller includes a counter configured to determine, based on a first voltage input to the inductor, an on-time of the diode. The on-time of the diode corresponds to an amount of time that the diode is conducting a first current to a load of the power conversion circuit. A current estimation circuit configured to estimate, based on the on-time of the diode and an on-time of the switch, an output current of the power conversion circuit. The on-time of the switch corresponds to an amount of time that the switch is conducting a second current. A pulse width modulator is configured to provide, based on the estimated output current, a gate drive signal to the switch. The gate drive signal selectively transitions the switch between an on state and an off state.Type: ApplicationFiled: June 9, 2014Publication date: September 25, 2014Inventors: Wanfeng Zhang, Jianqing LIN, Shaoan DAI
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Publication number: 20140239825Abstract: Power converters that produce less noise are disclosed. For example, in an embodiment, power converter can include a first inductor magnetically coupled to a second inductor, wherein a first end of the second inductor is electrically open and a second end of the second inductor is electrically coupled to ground via a second capacitor, a transistor electrically connected to the first inductor, and control circuitry to control switching of the transistor, wherein when the transistor is repeatedly switched on and off by the control circuitry, a current loop is formed through the transistor, the second capacitor, the first inductor and the second inductor, the current loop causing a reduced amount of switching noise to be generated by the power converter.Type: ApplicationFiled: February 10, 2014Publication date: August 28, 2014Applicant: Marvell World Trade Ltd.Inventors: Jinho CHOI, Tuyen Doan, Yee-Huan Ng, Wanfeng Zhang
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Patent number: 8811046Abstract: In one embodiment, an apparatus includes a sampling component. The sampling component receives a first voltage signal on a primary side of a transformer and monitors the first voltage signal to determine a voltage sampling time. The determined voltage sampling time is when the first voltage signal is used to estimate a second voltage level on a secondary side of the transformer. The first component further samples the first voltage signal at the voltage sampling time to determine a first voltage level. A second component outputs a control signal to control a switch to regulate the second voltage level based on the first voltage level.Type: GrantFiled: June 13, 2011Date of Patent: August 19, 2014Assignee: Marvell World Trade Ltd.Inventors: Yangsoo Park, Jinho Choi, Wanfeng Zhang
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Publication number: 20140226371Abstract: A control signal circuit for estimating a current output from a transformer. The control signal circuit includes a converter circuit configured to receive a signal corresponding to a current input to the transformer and output, over a half line cycle, a plurality of values corresponding to the current output from the transformer. The half line cycle corresponds to a period that the transformer is connected to an input voltage. An output current estimator is configured to accumulate the values output from the converter circuit over the half line cycle, determine an average value of the current output from the transformer over the half line cycle, and output the average value of the current output from the transformer over the half line cycle.Type: ApplicationFiled: April 21, 2014Publication date: August 14, 2014Applicant: Marvell World Trade Ltd.Inventors: Jinho CHOI, Yangsoo PARK, Wanfeng ZHANG
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Patent number: 8803438Abstract: Aspects of the disclosure provide a circuit that includes a detection circuit and a controller. The detection circuit is configured to detect a starting of a conduction in a power supply provided via an electronic transformer. The controller is configured to control a current regulating circuit to pull a current from the electronic transformer at a pre-determined level during a time duration following the starting of the conduction, and pull the current at a reduced level according to a pre-determined profile after the time duration.Type: GrantFiled: December 19, 2012Date of Patent: August 12, 2014Assignee: Marvell World Trade Ltd.Inventors: Pantas Sutardja, InHwan Oh, Wanfeng Zhang
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Publication number: 20140217916Abstract: A system including first and second lamps, one of an inductor or a transformer, first and second switches, and a control module. The first lamp generates a first output of light having a first color. The second lamp generates a second output of light having a second color. The first and second outputs of light are mixed to provide a mixture of light having a third color. The transformer includes first and second coils. The first and second coils supply power respectively to the first and second lamps. The first and second switches are connected respectively to the first and second coils. The control module alters the third color by controlling (i) a state of the first switch to adjust a first amount of current supplied to the first lamp, and (ii) a state of the second switch to adjust a second amount of current supplied to the second lamp.Type: ApplicationFiled: April 14, 2014Publication date: August 7, 2014Applicant: Marvell World Trade LTD.Inventors: Wanfeng Zhang, Jinho Choi
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Patent number: 8796954Abstract: In one embodiment, an apparatus includes circuitry configured to receive a dimming input to control a dimming level of a lamp. Also, the apparatus includes circuitry configured to generate a control signal based on the dimming input. The control signal indicates the dimming level for a converter of the lamp and the converter is configured to interpret the control signal to control to the dimming level of the lamp using a sinusoidal signal.Type: GrantFiled: October 13, 2011Date of Patent: August 5, 2014Assignee: Marvell World Trade Ltd.Inventors: Wanfeng Zhang, Radu Pitigoi-Aron, Daniel Reed
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Patent number: 8786205Abstract: Aspects of the disclosure provide a circuit. The circuit includes a first switch, a second switch and a controller. The first switch is switched on and off to allow a boost circuit to transfer electric energy from an input power supply to a capacitor to generate an intermediate power supply having a higher voltage than the input power supply. The second switch is switched on and off to allow a buck circuit to provide a driving voltage based on the intermediate power supply to drive a load device, and to regulate a current to the load device. The controller is configured to provide a first signal to the first switch and a second signal to the second switch to switch on and off the first switch and the second switch.Type: GrantFiled: August 14, 2012Date of Patent: July 22, 2014Assignee: Marvell World Trade Ltd.Inventors: Wanfeng Zhang, InHwan Oh