Patents by Inventor Kafai Leung

Kafai Leung 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).

  • Patent number: 7188199
    Abstract: DMA controller for mixed signal device. A mixed signal integrated circuit with memory control is disclosed. A data conversion circuit is provided that is operable to receive an analog input signal and convert discrete samples thereof at a predetermined sampling rate to a digital representations thereof as a plurality of digital words. A memory stores the digital words generated by the data conversion circuit. A processor is included on the integrated circuit and operable to access the memory to output select ones of the digital words for processing thereof in accordance with a predetermined processing algorithm. A memory access controller controls access to the memory by the data conversion circuit and the processor.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: March 6, 2007
    Assignee: Silicon Labs CP, Inc.
    Inventors: Kafai Leung, Ka Y. Leung
  • Publication number: 20060279969
    Abstract: A distributed power system for delivering DC power to a plurality of loads. A plurality of switching DC/DC converter modules are provided, each disposed proximate one of the loads, and each having associated therewith a switching pulse generator for generating switching pulses. A distributed power line distributes input power to each of the modules and a data communication line distributes command data between the modules, each of the modules uniquely addressable over the data communication line. A timing communication line is also provided for distributing timing information to each of the switching pulse generators. A master controller generates commands and communicates them to the data modules over the data communication line, the master controller operable to generate timing information over the timing communication line to each of the modules for controlling the associated switching pulse generator.
    Type: Application
    Filed: March 31, 2006
    Publication date: December 14, 2006
    Applicant: SILICON LABORATORIES INC.
    Inventors: Kafai Leung, Ka Leung, Donald Alfano
  • Publication number: 20060244570
    Abstract: A distributed power system for delivering DC power to a plurality of loads. A plurality of power converter modules having associated therewith a DC/DC power conversion operation are provided, each disposed proximate an associated one of the loads, each of said converter modules having associated therewith a switching pulse generator for generating switching pulses. A distributed power line distributes input power to each of the modules. A data communication line distributes command data between the modules. Each of the modules includes a power regulation section for receiving the input power to generate a DC output by controlling the operation of the switching pulse generator. It also includes a processing section for interfacing with the data communication line for interfacing with the commands, the processing function operating in at least a slave mode to receive commands from the data communication bus. At least one of the modules operates in both a slave mode and a master mode.
    Type: Application
    Filed: March 31, 2006
    Publication date: November 2, 2006
    Applicant: SILICON LABORATORIES INC.
    Inventors: Kafai Leung, Ka Leung, Donald Alfano
  • Publication number: 20060220938
    Abstract: A digital controller for controlling the operation of a DC-DC switching converter is disclosed. A digital feedback control system is provided for receiving an analog input voltage representing the output of the switching converter and digitally processing the analog input voltage by comparing it to a reference voltage and then determining analog drive signals to control the operation of the switching converter to provide a regulated output. The digital feedback control system operates in accordance with predetermined operating parametrics. The digital feedback control system also has monitoring inputs and control inputs. A microcontroller monitors the operation of the digital feedback control system and is able to change the operating parametrics under certain predetermined conditions.
    Type: Application
    Filed: March 31, 2005
    Publication date: October 5, 2006
    Inventors: Ka Leung, Kafai Leung, Jinwen Xaio, Chia-Ling Wei, Alvin Storvik, Biranchinath Sahu, Donald Alfano
  • Patent number: 7113011
    Abstract: A timing source for a pulse generator is disclosed, which timing source includes an input for receiving a reference clock output at a reference operating frequency. An edge generator is provided for generating a plurality of clock edges from an edge of the reference clock during one period thereof, with the spacing of the plurality of clock edges being a multiple of a predetermined divisor. As such, the resolution of such spacing emulates a higher clock frequency than the reference operating frequency. A selector then selects one of the plurality of clock edges from a reference one thereof to define the width of a pulse.
    Type: Grant
    Filed: June 21, 2004
    Date of Patent: September 26, 2006
    Assignee: Silicon Laboratories Inc.
    Inventors: Ka Y. Leung, Kafai Leung
  • Publication number: 20060172783
    Abstract: A power converter is disclosed for receiving an input voltage and converting it to a DC output voltage at a different voltage level than the input voltage. It includes a switching power converter for receiving the input voltage on an input and converting the input voltage to an output as the DC output voltage in response to pulse control signals. A switching controller is provided for generating the pulse control signals during a switching cycle and a processor controls the switching controller to define the length and initiation of the switching cycle. A communication interface interfaces with a first data communication bus for receiving data therefrom and with a second communication bus for receiving timing information therefrom.
    Type: Application
    Filed: March 31, 2006
    Publication date: August 3, 2006
    Inventors: Kafai Leung, Ka Leung, Donald Alfano
  • Publication number: 20060083037
    Abstract: A method for optimizing the efficiency of a digital power supply having at least one switch for connecting an input voltage to an input node for driving an inductive storage element connected to an out put node tp provide a regulated output voltage, and a second switch for shunting the intermediate node to ground in a complementary operation. Complementary switch control signals are generated for controlling the operation of the first and second switches, wherein the ratio of the on and off time of the first switch determines the ratio of the output voltage to the input voltage. The duty cycle is then controlled to provide a regulated voltage on the output node. A delay circuit provides a delay between the time the first switch is turned off and the second switch is turned on. For a given load, the delay is varied and then a minima for the delay is determined to provide the minimum duty cycle for the given load.
    Type: Application
    Filed: December 1, 2005
    Publication date: April 20, 2006
    Inventors: Ka Leung, Chia Wei, Kafai Leung, Ross Fosler
  • Publication number: 20060033650
    Abstract: A method is disclosed for generating pulse width modulated pulse control signals for controlling switches in a switching power supply. First, a count value is determined of a master clock within a switching cycle of the power supply from beginning to end thereof. A separate state machine providing for each edge in each of pulse control signals and each is operated to generate the associated edge as a function of the sum of a fixed reference count value from the beginning of the switching cycle and a determined count value when the sum is determined to equal the actual count value.
    Type: Application
    Filed: June 30, 2005
    Publication date: February 16, 2006
    Inventors: Ka Leung, Kafai Leung
  • Publication number: 20060022731
    Abstract: An apparatus for providing over current protection for a digital pulse width modulator is disclosed. The apparatus includes first logic circuitry for generating a primary interrupt indicating that a detected output current is greater than a threshold current. Second logic circuitry generates a secondary input responsive to the occurrence to the primary interrupt for a predetermined number of times.
    Type: Application
    Filed: March 31, 2005
    Publication date: February 2, 2006
    Inventors: Kafai Leung, Ka Leung, Donald Alfano
  • Publication number: 20060022656
    Abstract: A system for controlling a switching power converter and includes a digital controller that receives an analog signal representing the output DC voltage of the power converter for comparison to a desired output voltage level and generates switching control signals to control the operation of the power supply to regulate the output DC voltage to said desired output voltage level. At least two of the switching control signals having a dead time between a first edge of a first control signal and a second edge of a second control signal. The dead time is programmable such that the second edge of the second control signal may occur at a selected point in time either before or after the first edge of the first control signal.
    Type: Application
    Filed: June 30, 2005
    Publication date: February 2, 2006
    Inventors: Kafai Leung, Ka Leung
  • Publication number: 20060022851
    Abstract: An apparatus for forcing outputs of a digital controller of a switching power converter to a safe state during shutdown of the switching power converter is described. The apparatus includes a multiplexer providing an output signal of the digital controller and having a first input of the multiplexer connected to receive a switching control signal control signal from the digital controller. The multiplexer also has a plurality of inputs from control registers providing programmed safe state values. The multiplexer connects one of the first input or the inputs from the plurality of control registers to the output of the multiplexer responsive to a multiplexer control signal. Control logic generates the multiplexer control signal responsive to at least one of an end of frame interrupt, an over current interrupt, an enable interrupt or a software bypass signal.
    Type: Application
    Filed: June 30, 2005
    Publication date: February 2, 2006
    Inventors: Ka Leung, Kafai Leung, Donald Alfano
  • Publication number: 20060022852
    Abstract: A monolithic digital power supply controller is disclosed for controlling the operation of a switched power supply. The controller is contained within an integrated circuit package enclosing an integrated circuit chip. A plurality of inputs are provided on the package for interfacing with the switched power supply for receiving sensed inputs therefrom. A plurality of outputs provide switch control signals for turning on and off switches in the switched power supply. An integrated digital controller on the chip receives the inputs and generates the outputs, and includes an integrated instruction based processing engine for providing a portion of the digital control of the digital controller. A memory associated with the processing engine stores instructions for the processing engine.
    Type: Application
    Filed: June 30, 2005
    Publication date: February 2, 2006
    Inventors: Ka Leung, Kafai Leung, Jinwen Xaio, Chia-Ling Wei, Alvin Storvik, Biranchinath Sahu, Donald Alfano
  • Publication number: 20060023781
    Abstract: A method is disclosed for optimizing the efficiency of a digital switched power supply having a plurality of switches responsive to generated pulse control signals. The process involves varying the initiation of conduction in at least one of the switches relative to the conduction in another of the switches by controlling when an edge in an associated one of the pulse control signals is generated. The current to the power supply is measured during the step of varying and a minima in the measured current determined over the step of varying. After the step of determining, the configuration of the respective pulse control signals at the minima is frozen.
    Type: Application
    Filed: June 30, 2005
    Publication date: February 2, 2006
    Inventors: Ka Leung, Kafai Leung
  • Publication number: 20060022732
    Abstract: An apparatus for providing over current protection for a digital pulse width modulator is disclosed. The apparatus includes first logic circuitry for generating a primary interrupt indicating that a detected output current is greater than a threshold current. Second logic circuitry blanks out current spikes in the output current occurring on a leading pulse edge of at least one of a plurality of outputs of the digital pulse-width modulator.
    Type: Application
    Filed: March 31, 2005
    Publication date: February 2, 2006
    Inventors: Kafai Leung, Ka Leung, Jinwen Xiao
  • Publication number: 20060023479
    Abstract: A digital PID controller for controlling the operation of a switching power converter is disclosed. A data converter is provided for converting the analog sense voltage to a digital sense voltage. A difference circuit then determines the difference between the digital sense voltage and a reference voltage as a digital error voltage, which reference voltage represents a desired output DC voltage for the power converter. A digital compensator processes the digital error voltage. The digital compensator includes a PID compensation network for compensating the digital error signal with a discrete time PID control law and a postprocessing filter for processing the output of the PID compensation network, comprised of a sinc filter with variable parameters to define the operating characteristics thereof, such that a first notch associated therewith can be placed at a desired frequency.
    Type: Application
    Filed: March 31, 2005
    Publication date: February 2, 2006
    Inventors: Ka Leung, Kafai Leung, Jinwen Xiao
  • Publication number: 20050280458
    Abstract: A timing source for a pulse generator is disclosed, which timing source includes an input for receiving a reference clock output at a reference operating frequency. An edge generator is provided for generating a plurality of clock edges from an edge of the reference clock during one period thereof, with the spacing of the plurality of clock edges being a multiple of a predetermined divisor. As such, the resolution of such spacing emulates a higher clock frequency than the reference operating frequency. A selector then selects one of the plurality of clock edges from a reference one thereof to define the width of a pulse.
    Type: Application
    Filed: June 21, 2004
    Publication date: December 22, 2005
    Inventors: Ka Leung, Kafai Leung
  • Patent number: 6891487
    Abstract: Capacitor calibration in SAR converter. A method for calibrating a switched capacitor array in a SAR data converter is disclosed, which array includes a plurality of primary capacitors having a common node plate interfaced to a common node and a switched plate interfaced to a switch that is operable to be switched between first and second reference voltages. A comparator having an input connected to the common node and a reference input connected to a comparator reference node receives a comparator reference voltage. In a first calibration step for calibrating one of the primary capacitors, a reference capacitor is provided and then, the switched plate of the select primary capacitor is connected to the first reference voltage, the switched plate of the other capacitors and the reference capacitor are connected to the second reference voltage, and the common node and the comparator reference node are driven with a driver to dispose a first voltage thereon.
    Type: Grant
    Filed: January 7, 2004
    Date of Patent: May 10, 2005
    Assignee: Silicon Labs CP, Inc.
    Inventors: Ka Y. Leung, Douglas R. Holberg, Kafai Leung
  • Patent number: 6882298
    Abstract: Self calibrating SAR analog-to-digital converter. A data converter for converting analog data on a differential data input having a positive analog input terminal and a negative analog input terminal to digital data. The data converter includes a first single ended successive approximation register (SAR) analog-to-digital converter for converting the analog signal on the positive analog input terminal to a first digital signal and a second single ended successive approximation register (SAR) analog-to-digital converter for converting the analog signal on the negative analog input terminal to a second digital signal. A circuit for combining the first and second digital signals as a digital output signal for the data converter that represents the difference between the analog signals on the positive and negative analog input terminals.
    Type: Grant
    Filed: June 3, 2003
    Date of Patent: April 19, 2005
    Assignee: Silicon Labs CP, Inc.
    Inventors: Ka Y. Leung, Kafai Leung
  • Publication number: 20040267986
    Abstract: DMA controller for mixed signal device. A mixed signal integrated circuit with memory control is disclosed. A data conversion circuit is provided that is operable to receive an analog input signal and convert discrete samples thereof at a predetermined sampling rate to a digital representations thereof as a plurality of digital words. A memory stores the digital words generated by the data conversion circuit. A processor is included on the integrated circuit and operable to access the memory to output select ones of the digital words for processing thereof in accordance with a predetermined processing algorithm. A memory access controller controls access to the memory by the data conversion circuit and the processor.
    Type: Application
    Filed: January 7, 2004
    Publication date: December 30, 2004
    Inventors: Kafai Leung, Ka Y. Leung
  • Publication number: 20040246153
    Abstract: Capacitor calibration in SAR converter. A method for calibrating a switched capacitor array in a SAR data converter is disclosed, which array includes a plurality of primary capacitors having a common node plate interfaced to a common node and a switched plate interfaced to a switch that is operable to be switched between first and second reference voltages. A comparator having an input connected to the common node and a reference input connected to a comparator reference node receives a comparator reference voltage. In a first calibration step for calibrating one of the primary capacitors, a reference capacitor is provided and then, the switched plate of the select primary capacitor is connected to the first reference voltage, the switched plate of the other capacitors and the reference capacitor are connected to the second reference voltage, and the common node and the comparator reference node are driven with a driver to dispose a first voltage thereon.
    Type: Application
    Filed: January 7, 2004
    Publication date: December 9, 2004
    Inventors: Ka Y. Leung, Douglas R. Holberg, Kafai Leung