Patents Assigned to O2Micro International
  • Patent number: 7710317
    Abstract: The present invention is a method for GPS positioning in a weak signal environment. The method includes obtaining assistance data for a GPS signal from a satellite at a predetermined time, wherein the assistance data including predicted navigation data, Doppler shift and Doppler shift rate and the GPS signal being modulated by a carrier signal, a pseudorandom code and navigation data, estimating a predicted receiving time for the GPS signal reaching the GPS receiver, capturing the GPS signal, converting the GPS signal to an intermediate frequency signal, acquiring a code phase of the pseudorandom code from the intermediate frequency signal by using the assistance data and the predicted receiving time, and obtaining a position for the GPS receiver based on the predicted navigation data and the code phase of the pseudorandom code.
    Type: Grant
    Filed: February 3, 2006
    Date of Patent: May 4, 2010
    Assignee: O2Micro International Ltd.
    Inventors: MingQiang Cheng, Cheng Li, Bo Yu, ShiJie Li, Xiquan Yang, Yi Zeng
  • Patent number: 7701388
    Abstract: A positioning method using global positioning system (GPS) signal and digital broadcasting system (DBS) signal. The method includes detecting a presence status of the GPS signal through a signal detector in a receiver, detecting a presence status of the DBS signal through the signal detector, determining the signal strength of the GPS signal if the GPS signal is detected, determining the signal strength of the DBS signal if the DBS signal is detected, choosing one positioning mode among a plurality of positioning modes in a signal processing unit in the receiver based on signal presence status and the signal strength of a detected signal, and determining a location of the receiver based on the chosen positioning mode. The plurality of positioning modes includes stand-alone GPS mode, assisted GPS (AGPS) mode, assisted GPS positioning with DBS assist mode, DBS positioning with GPS assist mode, stand-alone DBS mode, and assist DBS mode.
    Type: Grant
    Filed: May 24, 2006
    Date of Patent: April 20, 2010
    Assignee: O2Micro International Ltd.
    Inventors: You-Yuh Jack Shyr, Mingqiang Cheng, Cuichai Ji
  • 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: 7688821
    Abstract: A data packets distributor for transferring a data packet from a source address to a destination address is provided. The data packet distributor has a plurality of predefined addresses and a data packet distributing unit. Each of the plurality of addresses indicates a network processing unit coupled to the data packet distributing unit. The data packet distributing unit is capable of forwarding a data packet to at least one of the plurality of predefined addresses for processing by using a first Network Address Translation (NAT) operation and further capable of forwarding the data packet to the destination address by using a second Network Address Translation (NAT) operation.
    Type: Grant
    Filed: November 21, 2006
    Date of Patent: March 30, 2010
    Assignee: O2Micro International Ltd.
    Inventor: Zhiming Wang
  • 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: 7668643
    Abstract: An exhaust emission data processing system for inspecting automatically exhaust emission of the vehicle and wirelessly transmitting exhaust emission inspection data to a remote server is provided. The system includes an exhaust emission processing module, a wireless connection module, and a remote server. The exhaust emission processing module receives OBD data indicating the exhaust emission inspection data from an OBD system embedded in the vehicle via an OBD connector. The exhaust emission processing module creates an exhaust emission inspection package with the vehicle identification and the exhaust emission inspection data. The exhaust emission processing module transmits the package to the remote server for further diagnosis through the wireless connection module. The remote server sends the diagnosis reports back to the vehicle through the wireless connection module.
    Type: Grant
    Filed: March 30, 2007
    Date of Patent: February 23, 2010
    Assignee: O2Micro International Ltd.
    Inventors: Xinsheng Peng, Xiaoguang Yu, Geen Sui
  • Patent number: 7659672
    Abstract: The present invention provides a flexible light emitter driver circuit which adjusts the luminance of the light emitter diodes (LED) by a manual input signal. The light emitter driver circuit comprises a Duty Ratio Change Logic, a PWM Generate and Control Logic, an oscillator, and a gate driver. The Duty Ratio Change Logic adjusts the duty cycle of the output signal according to the manual input signal. The PWM Generate and Control Logic generates a PWM signal according to the output signal to control the current of the LED, thus adjusts the luminance of the LED. The present invention further provides a highly flexible display system that comprises a light emitter driver circuit which can adjust the LED luminance by manual input signal.
    Type: Grant
    Filed: September 29, 2006
    Date of Patent: February 9, 2010
    Assignee: O2Micro International Ltd.
    Inventor: Shen Yang
  • 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: 7646169
    Abstract: Battery protection circuitry and method are disclosed. A battery is protected from a large current overdrawn condition by setting a discharge switch into a controllable conduction state. After the discharge switch is in the controllable conduction state, a tickle discharge current is gradually generated under control of a switch control signal. The trickle discharge current can be used to determine whether the large current overdrawn condition still exists. When the large current overdrawn condition is removed, the discharge switch is turned back on.
    Type: Grant
    Filed: September 29, 2006
    Date of Patent: January 12, 2010
    Assignee: O2Micro International Ltd.
    Inventors: Liusheng Liu, Bruce Denning
  • Patent number: 7643805
    Abstract: A variable gain amplifier (VGA) circuit and an automatic gain control (AGC) method thereof are disclosed. The VGA circuit includes an amplifier circuit and an AGC circuit. The amplifier circuit amplifies an input signal to an output signal according to a predetermined gain and the AGC circuit is connected to the amplifier circuit for regulating the predetermined gain. The AGC circuit further includes a peak detector detecting a peak of the output signal, a replica of the peak detector for detecting a peak of a reference signal, and a comparator for comparing the peak of the output signal with the peak of the reference signal to provide a control signal and then providing the control signal to the amplifier circuit to regulate the predetermined gain.
    Type: Grant
    Filed: July 7, 2006
    Date of Patent: January 5, 2010
    Assignee: O2Micro International Ltd.
    Inventors: Seeteck Tan, Xiaoyong Luo
  • 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: 7629771
    Abstract: A protection device for non-common ground buses is disclosed. The protection circuit includes a controller, a level shifter, a first group of switches, and a second group of switches. The controller together with the level shifter controls the first group and second group of switches. The non-common ground buses will be isolated when at least one group of the switches are turned off in an abnormal condition.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: December 8, 2009
    Assignee: O2Micro International, Ltd.
    Inventors: Guoxing Li, Shiqiang Liu, Sean Xiao
  • 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