Patents Assigned to O2Micro International Limited
  • Patent number: 7701177
    Abstract: A battery pre-charging circuit includes a pre-charging path, a pre-charging switch and a low-voltage pre-charging circuit. The pre-charging path is coupled between a charger and a battery for providing a pre-charging current from the charger to the battery. The pre-charging switch is coupled to the pre-charging path for conducting along the pre-charging path. The low-voltage pre-charging circuit is coupled to the pre-charging switch for controlling the pre-charging switch. The low-voltage pre-charging circuit is configured to switch on the pre-charging switch when the battery voltage is below a first battery voltage level.
    Type: Grant
    Filed: December 21, 2006
    Date of Patent: April 20, 2010
    Assignee: O2Micro International Limited
    Inventors: Shiqiang Liu, Guoxing Li, Sean Xiao, Liusheng Liu
  • Patent number: 7696725
    Abstract: A monitoring circuit for accurately monitoring a voltage level from each of a plurality of battery cells of a battery pack includes an analog to digital converter (ADC) and a processor. The ADC is configured to accept an analog voltage signal from each of the plurality of battery cells and convert each analog voltage signal to a digital signal representative of an accurate voltage level of each battery cell. The processor receives such signals and provides a safety alert signal based on at least one of the signals. The ADC resolution may be adjustable. A balancing circuit provides a balancing signal if at least two of the digital signals indicate a voltage difference between two cells is greater than a battery cell balance threshold. An electronic device including such monitoring and balancing circuits is also provided. Various methods are also provided.
    Type: Grant
    Filed: July 24, 2006
    Date of Patent: April 13, 2010
    Assignee: O2Micro International Limited
    Inventors: Liusheng Liu, Guoxing Li
  • Patent number: 7683577
    Abstract: A battery pack including at least one battery cell, a switch, and battery state monitoring circuitry. The battery state monitoring circuitry may be configured to control an ON resistance of the switch to a first ON resistance when the switch is ON and the battery pack is in a stand-by-state and to control the ON resistance to a second ON resistance when the switch is ON and said battery pack is not in said stand-by-state, the first ON resistance greater than the second ON resistance. A cordless electrical device and method consistent with embodiments are also provided.
    Type: Grant
    Filed: September 26, 2005
    Date of Patent: March 23, 2010
    Assignee: O2Micro International Limited
    Inventors: Constantin Bucur, Marian Niculae
  • Patent number: 7679324
    Abstract: A communication circuit is used for transmitting data between a plurality of devices which have non-common ground voltages. The communication circuit comprises a plurality of transmitting input nodes coupled to the devices, respectively, a transmitting current path, a plurality of receiving output nodes coupled to the devices, respectively, and a receiving current path. The transmitting current path is coupled to the transmitting input nodes. The current through the transmitting current path is varied according to the input signal of the transmitting input nodes. The receiving current path is coupled to the receiving output nodes. The current through the receiving current path is varied according to the current of the transmitting current path such that data is transmitted from the transmitting input nodes to the receiving output nodes.
    Type: Grant
    Filed: November 18, 2005
    Date of Patent: March 16, 2010
    Assignee: O2Micro International Limited
    Inventors: Sean Xiao, Oleksandr Kokorin
  • Patent number: 7667435
    Abstract: A secondary battery protection circuit may include an over voltage detector circuit configured to monitor a voltage level of an associated cell of a rechargeable battery and provide an output signal to a switch in response to a comparison of the voltage level of the cell to an over voltage threshold level. The switch may be coupled between the rechargeable battery and a DC power source and capable of moving between conducting and non-conducting states. The switch may also be responsive to the output signal to protect the rechargeable battery if the voltage level of said cell is greater than the over voltage threshold level for a time interval less than or equal to a transient time interval.
    Type: Grant
    Filed: July 6, 2007
    Date of Patent: February 23, 2010
    Assignee: O2Micro International Limited
    Inventor: Bruce S. Denning
  • Patent number: 7659702
    Abstract: A buck topology that provides voltage step up and polarity change is disclosed. In one embodiment a converter includes an input for receiving an input voltage, a switching circuit coupled to the input for receiving a first driving signal, a floating voltage source coupled to the switching circuit for producing an offset voltage, and an output coupled to the floating voltage source for generating an output voltage. The output voltage exhibits a voltage level that is directly proportional to a duty cycle of the first driving signal.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: February 9, 2010
    Assignee: O2Micro International Limited
    Inventors: Laszlo Lipcsei, Serban Popescu, Sorin Hornet
  • Publication number: 20100026213
    Abstract: A method according to one embodiment may include providing power to at least one light source. The method of this embodiment may also include detecting the frequency of at least one vertical synchronization signal, among a plurality of different synchronization signals, and controlling the power to at least one light source based on, at least in part, the detected frequency of at least one vertical synchronization signal. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Application
    Filed: October 6, 2009
    Publication date: February 4, 2010
    Applicant: O2Micro International Limited
    Inventors: Yung-Lin Lin, Albert Chang
  • Patent number: 7656684
    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: Grant
    Filed: April 29, 2008
    Date of Patent: February 2, 2010
    Assignee: O2Micro International Limited
    Inventors: Laszlo Lipcsei, Catalin Popovici
  • Patent number: 7656145
    Abstract: A voltage generator is used for generating a voltage reference with high power supply rejection. One embodiment of the circuit includes a voltage regulator and a bandgap voltage circuit and an amplifier. The voltage regulator including an input node is coupled to an external power supply for generating a regulated voltage source. A bandgap voltage circuit includes a first and a second resistor and a first and a second transistor to generate a voltage difference between the base-to-emitter voltages of the first and the second transistors. The second resistor is coupled to the first resistor and the first transistor for generating the first predetermined voltage in response to the voltage difference. An amplifier circuit is coupled to the first transistor of the bandgap voltage circuit for receiving a first amplifying signal and generating an amplified signal so as to regulate the regulated voltage source.
    Type: Grant
    Filed: June 19, 2007
    Date of Patent: February 2, 2010
    Assignee: O2Micro International Limited
    Inventors: Sean Xiao, Tom Tang, Guoxing Li
  • Publication number: 20100007350
    Abstract: An over voltage transient controller to protect a rechargeable battery from an over voltage transient condition. The over voltage transient controller may comprise a comparator to compare a first signal with a second signal representative of a reference voltage level and to provide an output signal representative of an over voltage transient condition to a switch if the first signal is greater than or equal to the second signal. The switch is responsive to the output signal to protect the rechargeable battery from the over voltage transient condition. The over voltage transient controller may further comprise a DAC, wherein the second signal is based, at least in part, on an output of the DAC. An apparatus comprising a charge switch and such an over voltage transient controller is also provided.
    Type: Application
    Filed: September 15, 2009
    Publication date: January 14, 2010
    Applicant: O2MICRO INTERNATIONAL LIMITED
    Inventors: Bruce S. Denning, Guoxing Li, Liusheng Liu
  • Patent number: 7642750
    Abstract: A circuit is used for controlling charging and discharging a battery. The circuit comprises a first MOSFET for controlling discharging the battery, and a second MOSFET coupled in series to the battery and the first MOSFET for controlling charging the battery. The first and second MOSFETs have body diodes respectively, and the first body diode of the first MOSFET and the second body diode of the second MOSFET are coupled in opposite directions. A load is coupled to the battery and a common node between the first and second MOSFETs such that power in the battery is delivered to said load when the first MOSFET is turned on. The circuit further comprises a power source coupled to the second switch in series and power is delivered from the power source to the battery when the first and second MOSFETs are turned on.
    Type: Grant
    Filed: August 22, 2006
    Date of Patent: January 5, 2010
    Assignee: O2Micro International Limited
    Inventors: Shiqiang Liu, Sean Xiao, Guoxing Li, Liusheng Liu
  • Patent number: 7622830
    Abstract: A supply topology comprising an AC to DC or DC to DC adapter and an electronic device with an active system, a battery, and an adapter controller implements closed-loop control of adapter output voltage to limit power consumption by the electronic device to a value related to maximum adapter power. The adapter couples a signal representing maximum adapter power to a control line connected to the electronic device and the electronic device couples an error signal representing the difference between instantaneous power consumption and adapter maximum power onto the same control line. The adapter adjusts its output voltage in response to the magnitude of the error signal. An adapter controller in the electronic device sets a limit for allocating current to battery charging from the signal representing maximum adapter power, with battery charging current approaching zero as instantaneous power consumption approaches maximum adapter power.
    Type: Grant
    Filed: September 13, 2006
    Date of Patent: November 24, 2009
    Assignee: O2Micro International Limited
    Inventors: Doru Cioaca, Constantin Bucur, Alexandru Hartular, Marian Niculae
  • Patent number: 7615981
    Abstract: A DC to DC converter for converting an input DC voltage to an output DC voltage. The DC to DC converter may include at least one switch, an inductor coupled to the at least one switch, and a controller capable of providing a control signal. The at least one switch may be responsive to the control signal in a first state to enter an ON state for an ON time interval, the ON time interval based on the input DC voltage and a constant. An electronic device including such a DC to DC converter and related methods are also provided.
    Type: Grant
    Filed: September 17, 2004
    Date of Patent: November 10, 2009
    Assignee: O2Micro International Limited
    Inventors: Foot Shen Wong, Ming Kwang Han, Vlad Mihail Popescu-Stanesti
  • Patent number: 7615965
    Abstract: A method according to one embodiment may include selecting at least one power supply, among a plurality of different power supplies, and coupling at least one available power supply to a load. The method may also include selecting at least one charging mode, among a plurality of different charging modes, to charge a rechargeable battery. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Grant
    Filed: August 27, 2004
    Date of Patent: November 10, 2009
    Assignee: O2Micro International Limited
    Inventors: Vlad Mihail Popescu-Stanesti, Jiwei Chen, Oleg Kobildjanov
  • Patent number: 7602620
    Abstract: A controller for providing out of phase drive signals to a power converter having at least a first power unit and second power unit. The controller may comprise input circuitry adapted to receive a first signal from a first path and a second signal from a second path and provide an output signal in response to a difference between the first and second signals. The first signal may be representative of a current level of the first power unit during a first time interval and the first signal representative of a current level of the second power unit during a second time interval. The controller may further comprise output circuitry responsive to the output signal from the input circuitry to provide the out of phase drive signals to the first and second power unit.
    Type: Grant
    Filed: December 30, 2004
    Date of Patent: October 13, 2009
    Assignee: O2Micro International Limited
    Inventors: Laszlo Lipcsei, Catalin Popovici
  • Patent number: 7599199
    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: Grant
    Filed: December 4, 2007
    Date of Patent: October 6, 2009
    Assignee: O2Micro International Limited
    Inventors: Laszlo Lipcsei, Catalin Popovici
  • Patent number: 7598679
    Abstract: A method according to one embodiment may include providing power to at least one light source. The method of this embodiment may also include detecting the frequency of at least one vertical synchronization signal, among a plurality of different synchronization signals, and controlling the power to at least one light source based on, at least in part, the detected frequency of at least one vertical synchronization signal. Of course, many alternatives, variations, and modifications are possible without departing from this embodiment.
    Type: Grant
    Filed: February 3, 2005
    Date of Patent: October 6, 2009
    Assignee: O2Micro International Limited
    Inventors: Yung-Lin Lin, Yu-Cheng Chang
  • Patent number: 7598718
    Abstract: A DC to DC converter to convert an input voltage to an output voltage. The DC to DC converter may include a pair of switches including a high side switch and a low side switch, an inductor coupled to the pair of switches; and a controller. The controller may be configured to estimate a zero crossing of an inductor current through the inductor without directly measuring said inductor current. An associated method is also provided.
    Type: Grant
    Filed: April 10, 2007
    Date of Patent: October 6, 2009
    Assignee: O2Micro International Limited
    Inventors: Laszlo Lipcsei, Serban-Mihai Popescu
  • Patent number: 7596806
    Abstract: The present invention provides an integrated VPN/firewall system that uses bath hardware (firmware) and software to optimize the efficiency of both VPN and firewall functions. The hardware portions of the VPN and firewall are designed in flexible and scalable layers to permit high-speed processing without sacrificing system security. The software portions are adapted to provide interfacing with hardware components, report and rules management control.
    Type: Grant
    Filed: September 8, 2003
    Date of Patent: September 29, 2009
    Assignee: O2Micro International Limited
    Inventor: Jyshyang Chen
  • Patent number: 7592777
    Abstract: A current mode charger controller for controlling a DC to DC converter. The current mode charger may include a first error amplifier having an output coupled to a common node. The first error amplifier may be configured to compare a first signal representative of a charging current provided to a rechargeable battery with a maximum charging current and provide a current control signal in response to the comparison. The current mode charger controller may further include an internal compensation network coupled to the common node, and a comparator configured to compare an inductor current signal representative of an inductor current through an inductor of the DC to DC converter with a compensation signal. The need for any external compensation for the current mode charger controller may be eliminated.
    Type: Grant
    Filed: November 18, 2005
    Date of Patent: September 22, 2009
    Assignee: O2Micro International Limited
    Inventors: Chun Lu, You-Yuh Shyr, Alexandru Hartular, Constantin Bucur