Patents by Inventor Nai-Chi Lee

Nai-Chi Lee 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: 6844702
    Abstract: A system, method and apparatus for contact-less charging of battery operated devices, including a host charger with a power converter and resonant tank circuit and a portable device where the battery is located, with a battery charging control IC, wherein the method obviates the need for a voltage controller in each of both the host and the portable stages. The charging of the battery in the portable device is controlled by a charging controller therein, which is in continual electric communication with the host, whose output power the control IC dynamically monitors and controls. In one embodiment, component count is minimized but battery charging is not optimized when the battery voltage is very low. In the other embodiment, charging efficiency is maximized regardless of the output voltage of the battery.
    Type: Grant
    Filed: May 16, 2002
    Date of Patent: January 18, 2005
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Demetri Giannopoulos, Qiong M Li, Nai-Chi Lee
  • Patent number: 6788555
    Abstract: A bi-directional flyback circuit includes a primary side switch that regulates the re-circulated energy to achieve substantially zero voltage switching (ZVS) and a secondary-side switch that regulates the output voltage. No feedback circuit between an output side and an input side of the bi-directional flyback circuit is needed for regulating the output voltage. The amount of recirculating energy required to achieve ZVS, and to maintain output regulation is kept substantially at a minimum.
    Type: Grant
    Filed: September 26, 2002
    Date of Patent: September 7, 2004
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Laurence Bourdillon, Demetri Giannopoulos, Nai-Chi Lee
  • Publication number: 20040062061
    Abstract: A bi-directional flyback circuit includes a primary side switch that regulates the re-circulated energy to achieve substantially zero voltage switching and a secondary-side switch that regulates the output voltage. No feedback circuit between an output side and an input side of the bi-directional flyback circuit is needed for regulating the output voltage.
    Type: Application
    Filed: September 26, 2002
    Publication date: April 1, 2004
    Applicant: Koninklijke Philips Electronics N. V.
    Inventors: Laurence Bourdillon, Demetri Giannopoulos, Nai-Chi Lee
  • Patent number: 6674655
    Abstract: A power supply comprising a flyback converter and a controller is disclosed. The flyback converter drives a load when electrically coupled to an alternating current power source. The controller controls a soft switching during each switching time period of the flyback converter. Upon an initial switching time period, the controller determines each acceptable switching frequency for the subsequent switching time periods and selects one of the acceptable switching frequencies for soft switching the flyback converter over one or more switching time periods during a constant load.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: January 6, 2004
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Demetri Giannopoulos, Nai-Chi Lee, Qiong Li
  • Publication number: 20030214821
    Abstract: A system, method and apparatus for contact-less charging of battery operated devices is presented. There is a host charger with a power converter and resonant tank circuit and a portable device where the battery is located, with a battery charging control IC. The method obviates the need for a voltage controller in each of both the host and the portable stages, thus decreasing complexity and increasing efficiency. The charging of the battery in the portable device is controlled by a charging controller therein, which is in continual electric communication with the host, whose output power the control IC dynamically monitors and controls. Two embodiments for the charging circuitry in the portable device are presented. In one embodiment component count is minimized but battery charging is not optimized when the battery voltage is very low. In the other embodiment charging efficiency is maximized regardless of the output voltage of the battery, but additional components are utilized.
    Type: Application
    Filed: May 16, 2002
    Publication date: November 20, 2003
    Applicant: Koninklijke Philips Electronics N.V.
    Inventors: Demetri Giannopoulos, Qiong M. Li, Nai-Chi Lee
  • Patent number: 6563718
    Abstract: A power converter apparatus employing a capacitively coupled feedback network for facilitating bi-directional communication between a primary and secondary side of the converter while maintaining direct current isolation.
    Type: Grant
    Filed: December 6, 2001
    Date of Patent: May 13, 2003
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Qiong Michelle Li, Nai-Chi Lee
  • Patent number: 6549432
    Abstract: A multiple-output, bi-directional flyback converter with soft switching of an input switch is disclosed. The primary-side of the converter is comprised of an input power supply, a transformer with a primary winding and a secondary winding, and an input switch with an associated diode, wherein a first end of the primary winding is connected to the input power supply and a second end of the primary winding is connected to the input switch. A first predetermined number of output voltage circuits are connected to a single secondary winding or one of a plurality of secondary windings each producing an output voltage. Each output voltage circuit has an output switch with an associated diode, and a diode connected in series between the output voltage switch and the secondary winding. A last output voltage circuit with a bi-directional switch and associated diode is connected connection to the secondary winding.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: April 15, 2003
    Assignee: Koninklijke Philips Electronics N.V.
    Inventors: Demetri Giannopoulos, Laurence Bourdillon, Nai-Chi Lee
  • Patent number: 6510066
    Abstract: A switch mode power supply (SMPS) and method are provided. In particular, the present invention provides an SMPS in which data is encoded by manipulating voltage pulses on a primary side. The manipulated voltage pulses are then transferred over a transformer to a secondary side. Secondary side pulses generated in response to the primary side pulses are sensed and decoded by a detector. The present invention allows data to be transferred from the primary side to the secondary side without affecting output voltages.
    Type: Grant
    Filed: March 30, 2001
    Date of Patent: January 21, 2003
    Inventors: Demetri Giannopoulos, Qiong Li, Nai-Chi Lee
  • Publication number: 20020141210
    Abstract: A switch mode power supply (SMPS) and method are provided. In particular, the present invention provides an SMPS in which data is encoded by manipulating voltage pulses on a primary side. The manipulated voltage pulses are then transferred over a transformer to a secondary side. Secondary side pulses generated in response to the primary side pulses are sensed and decoded by a detector. The present invention allows data to be transferred from the primary side to the secondary side without affecting output voltages.
    Type: Application
    Filed: March 30, 2001
    Publication date: October 3, 2002
    Applicant: KONINKLIJKE PHILIPS ELECTRONICS N.V.
    Inventors: Demetri Glannopoulos, Qiong Li, Nai-Chi Lee
  • Publication number: 20020085394
    Abstract: A power supply comprising a flyback converter and a controller is disclosed. The flyback converter drives a load when electrically coupled to an alternating current power source. The controller controls a soft switching during each switching time period of the flyback converter. Upon an initial switching time period, the controller determines each acceptable switching frequency for the subsequent switching time periods and selects one of the acceptable switching frequencies for soft switching the flyback converter over one or more switching time periods during a constant load.
    Type: Application
    Filed: December 29, 2000
    Publication date: July 4, 2002
    Inventors: Demetri Giannopoulos, Nai-Chi Lee, Qiong Li
  • Patent number: 6400581
    Abstract: A method for reducing power losses in a semiconductor switching device in a switching power converter by continuously monitoring an instantaneous power dissipation signal in the switching device and creating an appropriate correction signal to optimize that parasitic power dissipation. A multitude of strobed current and voltage measurement signals associated with the switching device are obtained over a time period using a pair of analog-to-digital converters (ADCs). These measurement signals are used to calculate the multitude of instantaneous power signals, then to derive an average power dissipation signal for a complete cycle and create the correction signal based on a comparison with a reference signal in memory. The correction signal can be, derived in a computer via an algorithm or a look-up table, and would preferably provide a relative adjustment in the timings of the switching device.
    Type: Grant
    Filed: April 16, 2001
    Date of Patent: June 4, 2002
    Assignee: Koninklijke Philips Electronics N.V.
    Inventor: Nai-Chi Lee
  • Patent number: 6341073
    Abstract: A method for controlling a switching converter includes receiving a digitized waveform of a continuous switch parameter; analyzing the digitized waveform to detect a parameter local minimum; and opening the switch at a parameter local minimum. An apparatus implements the method preferably using a microcontroller and at least one waveform digitizer to determine instantaneous power dissipation. The microcontroller selects an optimum local minimum of the switching waveform to achieve optimum power dissipation.
    Type: Grant
    Filed: November 16, 2000
    Date of Patent: January 22, 2002
    Assignee: Philips Electronics North America Corporation
    Inventor: Nai-Chi Lee
  • Patent number: 6011387
    Abstract: To improve testability of analog or mixed analog/digital circuit modules mounted on a carrier, three-way switches are placed at input and output ports of the circuit modules. The switches can operate to establish signal connections between a test bus and core circuits inside the modules. The switches can also establish signal connections between the test bus and glue circuits disposed between the modules.
    Type: Grant
    Filed: December 19, 1997
    Date of Patent: January 4, 2000
    Assignee: Philips Electronics North America Corporation
    Inventor: Nai-Chi Lee
  • Patent number: 5936446
    Abstract: Pulse width modulation driver circuitry both limits and regulates the voltage that is applied to a load from a power source which provides a voltage that may far exceed the maximum safe load voltage. The driver circuitry includes a reactive filter coupled to the load, a voltage sensor for sensing the instantaneous voltage across the load, a timer, and a comparator. The reactive filter alternately takes in energy from the power source and discharges it into the load. The voltage sensor, timer, and comparator cooperate with a switch to modulate the application of power to the load and to the reactive filter in response to the instantaneous magnitudes of the load voltage and the power source voltage.
    Type: Grant
    Filed: October 30, 1996
    Date of Patent: August 10, 1999
    Assignee: Philips Electronics North America Corporation
    Inventor: Nai-Chi Lee
  • Patent number: 5731701
    Abstract: To improve testability of analog or mixed analog/digital circuit modules mounted on a carrier, three-way switches are placed at input and output ports of the circuit modules. The switches can operate to establish signal connections between a test bus and core circuits inside the modules. The switches can also establish signal connections between the test bus and glue circuits disposed between the modules.
    Type: Grant
    Filed: August 12, 1996
    Date of Patent: March 24, 1998
    Assignee: Philips Electronics North America Corporation
    Inventor: Nai-Chi Lee
  • Patent number: 5721511
    Abstract: A pulse width modulation driver is capable of regulating the average voltage applied to a load that is powered from a source having a wide range, e.g. 20 to 80 volts DC, of possible voltages. The driver cyclically interrupts the load current at a frequency which is substantially constant. This is particularly advantageous for driving frequency-sensitive loads such as motors.
    Type: Grant
    Filed: July 1, 1996
    Date of Patent: February 24, 1998
    Assignee: Philips Electronics North America Corporation
    Inventor: Nai-Chi Lee
  • Patent number: 5717329
    Abstract: To improve testability of analog or mixed analog/digital circuit modules mounted on a carrier, three-way switches are placed at input and output ports of the circuit modules. The switches can operate to establish signal connections between a test bus and core circuits inside the modules. The switches can also establish signal connections between the test bus and glue circuits disposed between the modules.
    Type: Grant
    Filed: March 20, 1995
    Date of Patent: February 10, 1998
    Assignee: Philips Electronics North America Corp.
    Inventor: Nai-Chi Lee
  • Patent number: 5705925
    Abstract: To improve testability of analog or mixed analog/digital circuit modules mounted on a carrier, three-way switches are placed at input and output ports of the circuit modules. The switches can operate to establish signal connections between a test bus and core circuits inside the modules. The switches can also establish signal connections between the test bus and glue circuits disposed between the modules.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: January 6, 1998
    Assignee: North American Philips Corporation
    Inventor: Nai-Chi Lee
  • Patent number: 5581176
    Abstract: To improve testability of analog or mixed analog/digital circuit modules mounted on a carrier, three-way switches are placed at input and output ports of the circuit modules. The switches can operate to establish signal connections between a test bus and core circuits inside the modules. The switches can also establish signal connections between the test bus and glue circuits disposed between the modules.
    Type: Grant
    Filed: May 24, 1993
    Date of Patent: December 3, 1996
    Assignee: North American Philips Corporation
    Inventor: Nai-Chi Lee
  • Patent number: RE37500
    Abstract: A system for providing testing capability of individual submodules on an integrated circuit module. A test bus having a plurality of conductors is connected to selected internal ports of said submodules through three-way analog switches. Each three-way analog switch provides the capability to observe and control an internal port through combination of the ON/OFF status of two transmission gates. Test patterns for controlling the transmission gates may be provided by onboard D flip-flops which are externally programmed to control or observe ports of an individual submodule.
    Type: Grant
    Filed: November 20, 1996
    Date of Patent: January 8, 2002
    Assignee: North American Philips Corporation
    Inventor: Nai-Chi Lee