Patents Assigned to O2Micro International Limited
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Patent number: 7701177Abstract: 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: GrantFiled: December 21, 2006Date of Patent: April 20, 2010Assignee: O2Micro International LimitedInventors: Shiqiang Liu, Guoxing Li, Sean Xiao, Liusheng Liu
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Patent number: 7696725Abstract: 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: GrantFiled: July 24, 2006Date of Patent: April 13, 2010Assignee: O2Micro International LimitedInventors: Liusheng Liu, Guoxing Li
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Patent number: 7683577Abstract: 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: GrantFiled: September 26, 2005Date of Patent: March 23, 2010Assignee: O2Micro International LimitedInventors: Constantin Bucur, Marian Niculae
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Patent number: 7679324Abstract: 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: GrantFiled: November 18, 2005Date of Patent: March 16, 2010Assignee: O2Micro International LimitedInventors: Sean Xiao, Oleksandr Kokorin
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Patent number: 7667435Abstract: 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: GrantFiled: July 6, 2007Date of Patent: February 23, 2010Assignee: O2Micro International LimitedInventor: Bruce S. Denning
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Patent number: 7659702Abstract: 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: GrantFiled: March 29, 2007Date of Patent: February 9, 2010Assignee: O2Micro International LimitedInventors: Laszlo Lipcsei, Serban Popescu, Sorin Hornet
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Publication number: 20100026213Abstract: 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: ApplicationFiled: October 6, 2009Publication date: February 4, 2010Applicant: O2Micro International LimitedInventors: Yung-Lin Lin, Albert Chang
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Patent number: 7656684Abstract: 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: GrantFiled: April 29, 2008Date of Patent: February 2, 2010Assignee: O2Micro International LimitedInventors: Laszlo Lipcsei, Catalin Popovici
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Patent number: 7656145Abstract: 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: GrantFiled: June 19, 2007Date of Patent: February 2, 2010Assignee: O2Micro International LimitedInventors: Sean Xiao, Tom Tang, Guoxing Li
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Publication number: 20100007350Abstract: 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: ApplicationFiled: September 15, 2009Publication date: January 14, 2010Applicant: O2MICRO INTERNATIONAL LIMITEDInventors: Bruce S. Denning, Guoxing Li, Liusheng Liu
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Patent number: 7642750Abstract: 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: GrantFiled: August 22, 2006Date of Patent: January 5, 2010Assignee: O2Micro International LimitedInventors: Shiqiang Liu, Sean Xiao, Guoxing Li, Liusheng Liu
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Patent number: 7622830Abstract: 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: GrantFiled: September 13, 2006Date of Patent: November 24, 2009Assignee: O2Micro International LimitedInventors: Doru Cioaca, Constantin Bucur, Alexandru Hartular, Marian Niculae
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Patent number: 7615981Abstract: 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: GrantFiled: September 17, 2004Date of Patent: November 10, 2009Assignee: O2Micro International LimitedInventors: Foot Shen Wong, Ming Kwang Han, Vlad Mihail Popescu-Stanesti
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Patent number: 7615965Abstract: 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: GrantFiled: August 27, 2004Date of Patent: November 10, 2009Assignee: O2Micro International LimitedInventors: Vlad Mihail Popescu-Stanesti, Jiwei Chen, Oleg Kobildjanov
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Patent number: 7602620Abstract: 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: GrantFiled: December 30, 2004Date of Patent: October 13, 2009Assignee: O2Micro International LimitedInventors: Laszlo Lipcsei, Catalin Popovici
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Patent number: 7599199Abstract: 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: GrantFiled: December 4, 2007Date of Patent: October 6, 2009Assignee: O2Micro International LimitedInventors: Laszlo Lipcsei, Catalin Popovici
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Patent number: 7598679Abstract: 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: GrantFiled: February 3, 2005Date of Patent: October 6, 2009Assignee: O2Micro International LimitedInventors: Yung-Lin Lin, Yu-Cheng Chang
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Patent number: 7598718Abstract: 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: GrantFiled: April 10, 2007Date of Patent: October 6, 2009Assignee: O2Micro International LimitedInventors: Laszlo Lipcsei, Serban-Mihai Popescu
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Patent number: 7596806Abstract: 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: GrantFiled: September 8, 2003Date of Patent: September 29, 2009Assignee: O2Micro International LimitedInventor: Jyshyang Chen
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Patent number: 7592777Abstract: 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: GrantFiled: November 18, 2005Date of Patent: September 22, 2009Assignee: O2Micro International LimitedInventors: Chun Lu, You-Yuh Shyr, Alexandru Hartular, Constantin Bucur