Patents by Inventor Wenkai Wu
Wenkai Wu 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: 8174250Abstract: A ripple regulator for providing a pulse width modulation (PWM) signal for regulating an output voltage of a power converter switching stage. The regulator including a ripple circuit for providing a ripple voltage; a comparison circuit for comparing the ripple voltage to an output of an error amplifier; and a PWM circuit producing the PWM signal and receiving an output of the comparison circuit and a clock signal input, the clock signal input determining a first edge of the PWM signal and the output of said comparison circuit determining a second edge of the PWM signal.Type: GrantFiled: October 6, 2008Date of Patent: May 8, 2012Assignee: International Rectifier CorporationInventors: Wenkai Wu, Ken Boyden, Rami Hamze
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Publication number: 20120043946Abstract: One embodiment of the invention includes regulation voltage system for a power supply system. The system includes a current sense system configured to generate a sense signal that represents an output current of the power supply system that is supplied to a load. The system also includes a positive voltage droop controller configured to provide a regulation voltage to the power supply system, the positive voltage droop controller setting the regulation voltage to one of a predetermined fixed reference voltage or a variable reference voltage based on the sense signal. The variable reference voltage can be less than the predetermined fixed reference voltage.Type: ApplicationFiled: August 19, 2010Publication date: February 23, 2012Inventors: WEI DONG, Xiao Xu, Wenkai Wu
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Publication number: 20120038331Abstract: Systems and devices for smooth light load operation in a DC/DC converter are presented. The disclosed systems and methods enable smooth discontinuous conduction mode (DCM)/continuous conduction mode (CCM) transition. The disclosed systems and methods of smooth light load operation in a DC/DC converter may also avoid the generation of sub-harmonics during light load operation. In an example embodiment, a rising ramp is used to control the ON time of the converter oscillator, while a falling ramp controls the OFF time. During DCM operation, the minimum value of the falling ramp is clamped. The clamping of the falling ramp ensures a substantially similar level of the error amplifier output in both CCM and DCM and avoids disturbances caused by a difference in the error amplifier outputs between the modes.Type: ApplicationFiled: August 10, 2010Publication date: February 16, 2012Applicant: Texas Instruments IncoporatedInventors: Wenkai Wu, Weidong Zhu, Hal Chen, Xuening Li
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Publication number: 20120032748Abstract: Systems and devices for ripple reduction in a DC/DC converter are presented. The disclosed systems and methods enable ripple reduction in discontinuous conduction mode (DCM) operation. In DCM, the inductor current peak to peak ripple may be reduced based on the load current. To achieve the reduction of the inductor peak to peak current ripple, a digital counter is used to count the time between consecutive PWM pulses. The digital output of the counter is used to control the pulse width modulation. As the digital output of the counter increases, the PWM on-time decreases. Since the PWM pulse is demanded by the load in DCM mode, the peak to peak inductor ripple is modulated by the counter, or, in turn, modulated by the load current.Type: ApplicationFiled: August 3, 2010Publication date: February 9, 2012Applicant: Texas Instruments IncorporatedInventors: Xuening Li, Hal Chen, Weidong Zhu, Wenkai Wu
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Patent number: 8067927Abstract: A control circuit for a multi-phase converter including an analog front-end circuit for receiving and processing an output voltage and current of the converter circuits and an average output current; a digital circuit for producing an output voltage reference for setting a desired output voltage of the converter; and an error circuit for comparing the output voltage reference and a parameter related to said output voltage and current for generating control signals for controlling the converter circuits, said error circuit including an Analog to Digital Converter circuit, further comprising a digital PWM generation circuit controlled by said Analog to Digital converter circuit for generating digital control signals for controlling the converter circuits.Type: GrantFiled: July 10, 2007Date of Patent: November 29, 2011Assignee: International Rectifier CorporationInventors: Wenkai Wu, George Schuellein
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Patent number: 7982441Abstract: A multiphase converter comprising a plurality of converter circuits, each converter circuit having series connected high and low side switches connected across a voltage bus with a common node provided therebetween, each of the common nodes connected through a respective inductor to an output node of the converter coupled to a load, the high and low side switches each being controlled by a control circuit to provide a desired output voltage at the output node, the control circuit including a first circuit for disabling and enabling at least one phase in response to a condition of the load, the circuit causing the high side switch to be turned on prior to the lower side switch when a disabled phase is enabled.Type: GrantFiled: February 13, 2008Date of Patent: July 19, 2011Assignee: International Rectifier CorporationInventors: Mark Crowther, Wenkai Wu, George Schuellein
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Patent number: 7944193Abstract: A pulse width (PWM) controller for a voltage converter having at least one switch, an Analog to Digital Converter (ADC) circuit for digitizing inputted state variables including a feedback voltage from an output of the voltage converter and a reference voltage for setting the output of the voltage converter and providing a digital error signal, and a Proportional Integration and Derivation (PID) circuit receiving the digital error signal and providing a digital duty cycle signal. The controller including a Digital to Analog Converter (DAC) circuit for converting the digital duty cycle signal into an analog DAC output signal; and a comparator circuit for comparing a first signal including the DAC output signal with a reference signal for generating a pulse width modulated control signal for controlling the switching of the at least one switch of the voltage converter.Type: GrantFiled: May 8, 2008Date of Patent: May 17, 2011Assignee: International Rectifier CorporationInventors: Wenkai Wu, Ken Boyden, Rami Hamze
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Patent number: 7888918Abstract: A control circuit for use in controlling a phase of a multi-phase voltage converter in accordance with an embodiment of the present invention includes a driver operable to provide a first control signal to a high side switch of a half-bridge of the phase and a second control signal to a low side switch of the half bridge, such that a desired output voltage is provided by the phase, current sensing circuitry operable to detect the output current of the phase, a comparator operable to compare the output current to a threshold current value and a disabling device operable to provide an enable/disable signal to disable the driver when the output current is below the threshold current value.Type: GrantFiled: August 8, 2007Date of Patent: February 15, 2011Assignee: International Rectifier CorporationInventors: Wenkai Wu, George Schuellein
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Patent number: 7816901Abstract: A PWM modulator for generating a PWM control signal for operating transistor switches of a phase of a multi-phase converter including a plurality of ramp generators, each ramp generator receiving a dedicated clock input signal corresponding to a phase of the multi-phase converter and providing a ramp signal starting when the dedicated clock signal is received by the ramp generator, one of the plurality of ramp generators being dedicated to provide the PWM control signal; a plurality of comparators, each comparator associated with a respective ramp generator for terminating the ramp signal when a predefined inequality exists between an error amplifier output of a feedback loop of the multi-phase converter and an output of the associated ramp generator; a plurality of current generator circuits, each current generator circuit associated with a respective ramp generator for providing current to the dedicated ramp generator to control the slope of the ramp signal of the dedicated ramp generator, the dedicated ramType: GrantFiled: October 19, 2007Date of Patent: October 19, 2010Assignee: International Rectifier CorporationInventors: Wenkai Wu, George Schuellein
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Patent number: 7733675Abstract: A circuit for preventing inductor saturation during a step-up load transient in a multi-phase converter circuit where phases are turned ON sequentially by a shared clock signal with a fixed phase shift, each phase having high- and low-side switches series connected at a switching node, the circuit including at least one closed loop connected to at least one phase for providing ripple current cancellation in input and output sides of the multi-phase converter circuit; an oscillator circuit for providing a signal to turn ON and OFF the high- and low-side switches of each of the phases of the multi-phase converter circuit; and a detection circuit to detect the transient. The detect circuit includes an error amplifier circuit to receive input signals from an output of the multi-phase converter and to provide an error signal; and a clock oscillator frequency changing circuit receiving the error signal for increasing the clock oscillation frequency when said detection circuit detects a step-up load transient.Type: GrantFiled: July 23, 2007Date of Patent: June 8, 2010Assignee: International Rectifier CorporationInventors: Wenkai Wu, George Schuellein
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Patent number: 7593200Abstract: A circuit for detecting faults in a converter, the converter including a switching stage having high- and low-side series switches connected together at a switching node and fault circuitry for managing a plurality of fault conditions, an input voltage source being provided at one terminal of the high-side switch. The circuit including a gate driver circuit connected to gate terminals of the high- and low-side switches for providing PWM signals to control the switching stage; a comparator circuit for comparing a voltage at the switching node to the input voltage and providing an output signal, the comparator circuit having output, positive and negative terminals; a capacitor connected to the output terminal of the comparator circuit to generate an AC component of the comparator circuit output signal; and a rectifier circuit connected to the capacitor for rectifying the AC component of the comparator circuit output signal and providing a fault-indicating signal to the gate driver circuit.Type: GrantFiled: August 14, 2007Date of Patent: September 22, 2009Assignee: International Rectifier CorporationInventors: Wenkai Wu, George Schuellein
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Publication number: 20090174380Abstract: A ripple regulator for providing a pulse width modulation (PWM) signal for regulating an output voltage of a power converter switching stage. The regulator including a ripple circuit for providing a ripple voltage; a comparison circuit for comparing the ripple voltage to an output of an error amplifier; and a PWM circuit producing the PWM signal and receiving an output of the comparison circuit and a clock signal input, the clock signal input determining a first edge of the PWM signal and the output of said comparison circuit determining a second edge of the PWM signal.Type: ApplicationFiled: October 6, 2008Publication date: July 9, 2009Inventors: Wenkai Wu, Ken Boyden, Rami Hamze
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Publication number: 20090015231Abstract: A pulse width (PWM) controller for a voltage converter having at least one switch, an Analog to Digital Converter (ADC) circuit for digitizing inputted state variables including a feedback voltage from an output of the voltage converter and a reference voltage for setting the output of the voltage converter and providing a digital error signal, and a Proportional Integration and Derivation (PID) circuit receiving the digital error signal and providing a digital duty cycle signal. The controller including a Digital to Analog Converter (DAC) circuit for converting the digital duty cycle signal into an analog DAC output signal; and a comparator circuit for comparing a first signal including the DAC output signal with a reference signal for generating a pulse width modulated control signal for controlling the switching of the at least one switch of the voltage converter.Type: ApplicationFiled: May 8, 2008Publication date: January 15, 2009Inventors: Wenkai Wu, Ken Boyden, Rami Hamze
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Patent number: 7449867Abstract: A multi-phase converter comprising 2N+1 inductors; and 2N+1 switching converters parallel connected and each including a switched node; wherein N is an even integer, a pair of said inductors are coupled and wound about a common core and each said coupled inductor is connected at one pole thereof to a respective switched node and at another pole thereof to an output node, and at least one of said inductors is uncoupled from the other inductors.Type: GrantFiled: July 21, 2006Date of Patent: November 11, 2008Assignee: International Rectifier CorporationInventors: Wenkai Wu, Nai-chi Lee, George Schuellein
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Publication number: 20080197823Abstract: A multiphase converter comprising a plurality of converter circuits, each converter circuit having series connected high and low side switches connected across a voltage bus with a common node provided therebetween, each of the common nodes connected through a respective inductor to an output node of the converter coupled to a load, the high and low side switches each being controlled by a control circuit to provide a desired output voltage at the output node, the control circuit including a first circuit for disabling and enabling at least one phase in response to a condition of the load, the circuit causing the high side switch to be turned on prior to the lower side switch when a disabled phase is enabled.Type: ApplicationFiled: February 13, 2008Publication date: August 21, 2008Applicant: INTERNATIONAL RECTIFIER CORPORATIONInventors: Mark Crowther, Wenkai Wu, George Schuellein
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Publication number: 20080094049Abstract: A PWM modulator for generating a PWM control signal for operating transistor switches of a phase of a multi-phase converter including a plurality of ramp generators, each ramp generator receiving a dedicated clock input signal corresponding to a phase of the multi-phase converter and providing a ramp signal starting when the dedicated clock signal is received by the ramp generator, one of the plurality of ramp generators being dedicated to provide the PWM control signal; a plurality of comparators, each comparator associated with a respective ramp generator for terminating the ramp signal when a predefined inequality exists between an error amplifier output of a feedback loop of the multi-phase converter and an output of the associated ramp generator; a plurality of current generator circuits, each current generator circuit associated with a respective ramp generator for providing current to the dedicated ramp generator to control the slope of the ramp signal of the dedicated ramp generator, the dedicated ramType: ApplicationFiled: October 19, 2007Publication date: April 24, 2008Inventors: Wenkai Wu, George Schuellein
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Publication number: 20080084717Abstract: A multi-phase converter comprising 2N+1 inductors; and 2N+1 switching converters parallel connected and each including a switched node; wherein N is an even integer, a pair of said inductors are coupled and wound about a common core and each said coupled inductor is connected at one pole thereof to a respective switched node and at another pole thereof to an output node, and at least one of said inductors is uncoupled from the other inductors.Type: ApplicationFiled: October 5, 2006Publication date: April 10, 2008Inventors: Wenkai Wu, Nai-chi Lee, George Schuellein
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Publication number: 20080054971Abstract: A pulse width modulation control circuit for providing a pulse width modulation signal in accordance with an embodiment of the present application includes a comparator operable to compare a first input to a second input and to provide the pulse width modulation signal based on the comparison, wherein the first input is an error signal and the second input is a ramp signal, wherein a first portion of the ramp is a decreasing ramp signal having a first slew rate and a second portion of the ramp signal is an increasing ramp signal having a second slew rate.Type: ApplicationFiled: July 6, 2007Publication date: March 6, 2008Inventors: Wenkai Wu, George Schuellein
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Publication number: 20080043499Abstract: A circuit for detecting faults in at least one converter in a converter system, the at least one converter including a switching stage having high- and low-side switches connected at a switching node and fault circuitry for managing a plurality of fault conditions. The circuit including a gate driver circuit connected to gate terminals of the high- and low-side switches for providing PWM signals to control the switching stage; a comparator circuit for comparing a voltage at the switching node to the input voltage and providing an output signal, the comparator circuit having output, positive and negative terminals; a fourth capacitor connected to the output terminal of the comparator circuit to generate an AC component of the comparator circuit output signal; and a rectifier circuit connected to the fourth capacitor for rectifying the AC component of the comparator circuit and providing a fault-indicating signal to the gate driver.Type: ApplicationFiled: August 14, 2007Publication date: February 21, 2008Inventors: Wenkai Wu, George Schuellein
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Publication number: 20080036526Abstract: A control circuit for use in controlling a phase of a multi-phase voltage converter in accordance with an embodiment of the present invention includes a driver operable to provide a first control signal to a high side switch of a half-bridge of the phase and a second control signal to a low side switch of the half bridge, such that a desired output voltage is provided by the phase, current sensing circuitry operable to detect the output current of the phase, a comparator operable to compare the output current to a threshold current value and a disabling device operable to provide an enable/disable signal to disable the driver when the output current is below the threshold current value.Type: ApplicationFiled: August 8, 2007Publication date: February 14, 2008Inventors: Wenkai Wu, George Schuellein