Patents Assigned to O2Micro International Limited
  • Low pass filter
    Patent number: 7471016
    Abstract: The present disclosure provides a method for filtering in a cordless electrical device. The method may include coupling a filter network, a microcontroller and a plurality of battery cells having a cell voltage and a current. The method may further include operatively connecting at least one switched capacitor low-pass filter to the plurality of battery cells, the at least one switched capacitor low-pass filter configured to receive a signal from the filter network. The method may also include filtering the signal from the filter network, delivering a filtered signal input to an ADC and generating an output from the ADC.
    Type: Grant
    Filed: December 15, 2006
    Date of Patent: December 30, 2008
    Assignee: O2Micro International Limited
    Inventors: Emanuel Stoicescu, Constantin Bucur
  • Circuit and method for trimming integrated circuits
    Patent number: 7436222
    Abstract: A programmable after-package, on-chip reference voltage trim circuit for an integrated circuit having a plurality of programmable trim cells generating a programmed sequence. A converter is provided to convert the bit sequence into a trim current. The trim current is added to an initial value of a reference voltage to be trimmed, as generated by the integrated circuit. Once the correct value of the trim current is determined, isolation circuitry is programmed to isolate the trim circuitry from the remainder of the IC, thereby freeing the logic and package pins associated with the IC for use by users of the IC. The preferred trim circuitry includes fuses which are blown in accordance with a bit value supplied to the trim cell to permanently fix a trim current value, once a best fit value is determined.
    Type: Grant
    Filed: January 15, 2008
    Date of Patent: October 14, 2008
    Assignee: O2Micro International Limited
    Inventors: You-Yuh Shyr, Sorin Laurentiu Negru
  • Power Converter
    Publication number: 20080232139
    Abstract: The present disclosure is directed towards a method for power conversion. The method may include controlling a first rectifier switch coupled to one end of a secondary winding of a transformer via a first control signal. The method may further include controlling a first low side switch via said first control signal, said first low side switch and a first high side switch coupled in series along a first path of a full bridge circuit, a first node located between said first high side switch and said first low side switch. The method may also include controlling a second rectifier switch coupled to an opposite end of said secondary winding via a second control signal.
    Type: Application
    Filed: April 29, 2008
    Publication date: September 25, 2008
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventors: Laszlo Lipcsei, Catalin Popovici
  • POWER MANAGEMENT TOPOLOGIES
    Publication number: 20080231117
    Abstract: A power supply topology according to one embodiment includes a first path coupled to a controllable DC power source, a second path coupled to a rechargeable battery, and a third path coupled to a system load, the three paths coupled to a common node. The topology may further include a unidirectional switch coupled to the first path and a selectively unidirectional switch coupled to the second path. The topology may further include a power management control circuit including a wake up circuit having a comparison circuit and an output decision circuit. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Application
    Filed: March 25, 2008
    Publication date: September 25, 2008
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventors: Constantin Bucur, Vlad Popescu-Stanesti, Marian Niculae, Daryl Nees
  • Power supply for an LCD panel
    Patent number: 7425949
    Abstract: A power supply system is provided for a multiple lamp LCD panel. In one aspect, the power supply includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series to thereby reduce the stress on each transformer. For LCD panels that include longer CCFLs, a power supply is provided that includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series and each lamp is coupled to two secondary sides of the transformers, thereby reducing the problems associated with longer CCFL tubes. In any of the embodiments, the power supply can be adapted to convert a high voltage DC signal to high voltage AC used to power the lamps.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: September 16, 2008
    Assignee: O2Micro International Limited
    Inventors: Yung-Lin Lin, Da Liu
  • Lamp Current Balancing Topologies
    Publication number: 20080211426
    Abstract: A method according to on embodiment may include generating AC voltage and current and a striking voltage. The method of this embodiment may also include generating striking voltage and steady-state voltage for at least two lamp loads. The method of this embodiment may also include coupling at least two lamp loads in parallel. The method of this embodiment may also include coupling current balancing circuitry to the at least two lamp loads and providing, by the current balancing circuitry simultaneous striking voltage to the at least two lamps loads. The method of this embodiment may also include balancing, by the current balancing circuitry, AC current through the at least two lamp loads. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Application
    Filed: May 13, 2008
    Publication date: September 4, 2008
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventors: Ching Chuan Kuo, Houng Kuo Hsu
  • Circuit structure for driving a plurality of cold cathode fluorescent lamps
    Publication number: 20080211305
    Abstract: A DC/AC converter circuit structure for driving a plurality of cold cathode fluorescent lamps is described. A common-mode choke is used between the cold cathode fluorescent lamps. The common-mode choke balances the currents respectively flowing through the cold cathode fluorescent lamps.
    Type: Application
    Filed: March 6, 2008
    Publication date: September 4, 2008
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventor: Sheng Tai Lee
  • High-efficiency adaptive DC/AC converter
    Patent number: 7417382
    Abstract: A CCFL power converter circuit is provided using a high-efficiency zero-voltage-switching technique that eliminates switching losses associated with the power MOSFETs. An optimal sweeping-frequency technique is used in the CCFL ignition by accounting for the parasitic capacitance in the resonant tank circuit. Additionally, the circuit is self-learning and is adapted to determine the optimum operating frequency for the circuit with a given load. An over-voltage protection circuit can also be provided to ensure that the circuit components are protected in the case of open-lamp condition.
    Type: Grant
    Filed: September 7, 2004
    Date of Patent: August 26, 2008
    Assignee: O2Micro International Limited
    Inventor: Yung-Lin Lin
  • Charging circuit for parallel charging in multiple battery systems
    Patent number: 7414381
    Abstract: A charging circuit for controlling a system charging parameter provided to a host of rechargeable batteries, wherein the host of batteries includes at least a first battery and second battery that may be coupled in parallel. The charging circuit provides for fast charging of rechargeable batteries in parallel. Independent current and voltage sensing for each battery enables parallel charging of batteries at different charging currents. The charging circuit may be configured to accept either analog or digital signals from an associated power management unit.
    Type: Grant
    Filed: June 20, 2006
    Date of Patent: August 19, 2008
    Assignee: O2Micro International Limited
    Inventors: Vlad Popescu-Stanesti, Marian Niculae, Constantin Bucur
  • Enhanced protocol conversion system capable of providing offloaded protocol instruction processing
    Patent number: 7412553
    Abstract: Systems are provided for the offloading of protocol control and conversion information within microprocessor-based systems. A converter controller comprises a first interface and protocol, as well as a second interface and protocol. An intermediate protocol and interface is interconnected to both the first protocol and the second protocol, and forwards or offloads protocol information to the system CPU, which comprises device driver information for protocol conversion and/or control. The CPU acts upon the received protocol information, performs protocol conversion as necessary, and forwards the converted protocol information back to the converter controller through the intermediate interface. Some embodiments of the offloading protocol conversion system comprise a SDIO controller within a USB-based device.
    Type: Grant
    Filed: September 6, 2005
    Date of Patent: August 12, 2008
    Assignee: O2Micro International Limited
    Inventor: Neil Morrow
  • Integrated circuit having reduced pin count
    Patent number: 7409484
    Abstract: A method according to one embodiment may include decoupling a CAUDIO/SPKR#/BVD2 signal line from a PC Card controller integrated circuit. The method of this embodiment may also include controlling, by the PC Card controller integrated circuit, at least one PC Card independently of the CAUDIO/SPKR#/BVD2 signal line. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Grant
    Filed: February 28, 2005
    Date of Patent: August 5, 2008
    Assignee: O2Micro International Limited
    Inventor: Neil Morrow
  • Cordless power tool with a protected weak link element
    Patent number: 7385795
    Abstract: A method consistent with an embodiment may include selecting one of a plurality of components of a power supply system of a cordless power tool to be a protected weak link element. The method may also include configuring the protected weak link element to fail from an overload condition before failure of a remainder of the plurality of components from the overload condition, monitoring a power condition of the protected weak link element, and protecting the protected weak link element from the overload condition to thereby also protect the remainder of the components from the overload condition. A battery pack and a cordless power tool are also provided.
    Type: Grant
    Filed: April 20, 2005
    Date of Patent: June 10, 2008
    Assignee: O2Micro International Limited
    Inventor: Bruce S. Denning
  • Circuit and Method for Trimming Integrated Circuits
    Publication number: 20080111576
    Abstract: A programmable after-package, on-chip reference voltage trim circuit for an integrated circuit having a plurality of programmable trim cells generating a programmed sequence. A converter is provided to convert the bit sequence into a trim current. The trim current is added to an initial value of a reference voltage to be trimmed, as generated by the integrated circuit. Once the correct value of the trim current is determined, isolation circuitry is programmed to isolate the trim circuitry from the remainder of the IC, thereby freeing the logic and package pins associated with the IC for use by users of the IC. The preferred trim circuitry includes fuses which are blown in accordance with a bit value supplied to the trim cell to permanently fix a trim current value, once a best fit value is determined.
    Type: Application
    Filed: January 15, 2008
    Publication date: May 15, 2008
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventors: You-Yuh Shyr, Sorin Negru
  • Lamp current balancing topologies
    Patent number: 7372213
    Abstract: A method according to on embodiment may include generating AC voltage and current and a striking voltage. The method of this embodiment may also include generating striking voltage and steady-state voltage for at least two lamp loads. The method of this embodiment may also include coupling at least two lamp loads in parallel. The method of this embodiment may also include coupling current balancing circuitry to the at least two lamp loads and providing, by the current balancing circuitry simultaneous striking voltage to the at least two lamps loads. The method of this embodiment may also include balancing, by the current balancing circuitry, AC current through the at least two lamp loads. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Grant
    Filed: October 19, 2005
    Date of Patent: May 13, 2008
    Assignee: O2Micro International Limited
    Inventors: Ching Chuan Kuo, Houng Kuo Hsu
  • Enhanced power switch device enabling modular USB PC cards
    Patent number: 7365454
    Abstract: An enhanced power switch device is provided for enabling modular USB PC cards. The enhanced power switch may include a card sense circuit for sensing the type of card present, a card power switching circuit for supplying power to a modular USB card, and isolation circuit for isolating conventional PC Card control signals from the modular USB card and a connection circuit for connecting USB signals to the USB Card. The system of the present invention can modified for other bus technologies, in addition to USB bus devices.
    Type: Grant
    Filed: April 22, 2003
    Date of Patent: April 29, 2008
    Assignee: O2Micro International Limited
    Inventor: Neil Morrow
  • Power converter
    Patent number: 7365995
    Abstract: A power converter may include a transformer having a primary winding and a secondary winding. A first high side switch and a first low side switch may be coupled in series along a first path of a full bridge circuit, having a first node between the first high side switch and the first low side switch. The power converter may also comprise a second high side switch and a second low side switch coupled in series along a second path of the full bridge circuit, having a second node between the second high side switch and the second low side switch. The power converter may further comprise a first path capable of providing a first rectifier drive signal from the first node to a second rectifier switch, and a second path capable of providing a second rectifier drive signal from the second node to a first rectifier switch.
    Type: Grant
    Filed: January 30, 2006
    Date of Patent: April 29, 2008
    Assignee: O2Micro International Limited
    Inventors: Laszlo Lipcsei, Catalin Popovici
  • Power Converter
    Publication number: 20080094858
    Abstract: A power converter includes a transformer having a primary winding and a secondary winding, and a plurality of switches coupled to the primary and secondary winding, the plurality of switches responsive to at least one control signal to short both the primary and secondary winding during a first reset time interval. An electronic device including such a power converter and related methods are also provided. A power converter having a plurality of DC to DC converters coupled in parallel is also provided.
    Type: Application
    Filed: December 4, 2007
    Publication date: April 24, 2008
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventors: Laszlo Lipcsei, Catalin Popovici
  • Power management topologies
    Patent number: 7348760
    Abstract: A wake up circuit according to one embodiment includes a comparison circuit and an output decision circuit. The comparison circuit may be adapted to receive a first signal representative of a charging current level provided to a battery via a path and a second signal representative of a predetermined wake up current level and to provide a comparison output signal in response to the first and second signal. The output decision circuit may be adapted to receive at least the comparison output signal and a selector signal from a selector circuit, the output decision circuit providing one of the comparison output signal and the selector signal to a switch to control a state of the switch, the switch coupled to the path.
    Type: Grant
    Filed: March 30, 2004
    Date of Patent: March 25, 2008
    Assignee: O2Micro International Limited
    Inventors: Constantin Bucur, Vlad Popescu-Stanesti, Marian Niculae, Daryl Nees
  • Circuit structure for driving a plurality of cold cathode flourescent lamps
    Patent number: 7345431
    Abstract: A DC/AC converter circuit structure for driving a plurality of cold cathode fluorescent lamps is described. A common-mode choke is used between the cold cathode fluorescent lamps. The common-mode choke balances the currents respectively flowing through the cold cathode fluorescent lamps.
    Type: Grant
    Filed: March 13, 2007
    Date of Patent: March 18, 2008
    Assignee: O2Micro International Limited
    Inventor: Sheng Tai Lee
  • Personal computer integrated with personal digital assistant
    Patent number: 7343484
    Abstract: A personal computer (PC) adapted to function as a personal digital assistant (PDA) includes: a central processing unit (CPU) responsive to a control signal to load a first operating system or a second operating system, wherein the first operating system is run by the PC in a first PC mode and the second operating system is run by the PC in a second PDA mode. A method of operating a personal computer (PC) in either a PC mode or a PDA mode is also provided that includes: initiating a control signal; and loading a first or second operating system based on the control signal, wherein the first operating system operates the PC is the first PC mode and the second operating system operates the PC is the second PDA mode.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: March 11, 2008
    Assignee: O2Micro International Limited
    Inventors: Sterling Du, Bruce Denning, James Lam