Patents by Inventor Stefan Maireanu
Stefan Maireanu 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).
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Patent number: 10797535Abstract: In accordance with some embodiments of the present invention, a method of determining a Q-factor in a transmit circuit with a resonant circuit includes setting a system voltage; performing a coarse scan to determine a course resonant frequency; performing a fine scan based on the course scan to determine a resonant frequency; performing a final measurement at the resonant frequency to determine an average system voltage and an average peak voltage of the resonant circuit; calculating a Q parameter from the average system voltage and the average peak voltage; and calculating the Q-factor from the Q parameter.Type: GrantFiled: October 8, 2018Date of Patent: October 6, 2020Assignee: Integrated Device Technology, Inc.Inventors: Nicholaus Smith, Stefan Maireanu, Haiwen Jiang, David Wilson
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Publication number: 20190109499Abstract: In accordance with some embodiments of the present invention, a method of determining a Q-factor in a transmit circuit with a resonant circuit includes setting a system voltage; performing a coarse scan to determine a course resonant frequency; performing a fine scan based on the course scan to determine a resonant frequency; performing a final measurement at the resonant frequency to determine an average system voltage and an average peak voltage of the resonant circuit; calculating a Q parameter from the average system voltage and the average peak voltage; and calculating the Q-factor from the Q parameter.Type: ApplicationFiled: October 8, 2018Publication date: April 11, 2019Inventors: Nicholaus Smith, Stefan Maireanu, Haiwen Jiang, David Wilson
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Patent number: 9130378Abstract: In a power converter, a primary winding receives an input power. In addition, multiple secondary windings transform the input power into multiple charging currents to charge a set of cells via a set of paths. The multiple secondary windings further balance the set of cells based on the charging currents. A ratio between a first turn number of a first secondary winding of the secondary windings and a second turn number of a second secondary winding of the secondary windings is determined by a nominal voltage ratio between two corresponding cells of the set of cells.Type: GrantFiled: November 27, 2013Date of Patent: September 8, 2015Assignee: O2Micro, Inc.Inventors: William Densham, Constantin Bucur, Flavius Lupu, Jiun Heng Goh, Stefan Maireanu
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Patent number: 8907625Abstract: A battery management chip may include a battery management unit and a vertical bus circuit. The battery management unit can monitor a cell status of multiple cells in a battery module coupled to the battery management chip in response to an instruction from a host processor. The vertical bus circuit may transfer the instruction from the host processor to the battery management unit. The vertical bus circuit may include a first receiver, a command processor and a first transmitter. The first receiver can receive a first pair of differential input data signals. The command processor can process the first pair of differential input data signals. The first transmitter can output a first pair of differential output data signals.Type: GrantFiled: July 15, 2011Date of Patent: December 9, 2014Assignee: O2Micro, Inc.Inventors: Allan Flippin, William Densham, Jiun Heng Goh, Constantin Bucur, Flavius Lupu, Stefan Maireanu
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Publication number: 20140084871Abstract: In a power converter, a primary winding receives an input power. In addition, multiple secondary windings transform the input power into multiple charging currents to charge a set of cells via a set of paths. The multiple secondary windings further balance the set of cells based on the charging currents. A ratio between a first turn number of a first secondary winding of the secondary windings and a second turn number of a second secondary winding of the secondary windings is determined by a nominal voltage ratio between two corresponding cells of the set of cells.Type: ApplicationFiled: November 27, 2013Publication date: March 27, 2014Applicant: O2Micro Inc.Inventors: William DENSHAM, Constantin BUCUR, Flavius LUPU, Jiun Heng GOH, Stefan MAIREANU
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Patent number: 8598844Abstract: In a power converter, a primary winding receives an input power. In addition, multiple secondary windings transform the input power into multiple charging currents to charge a set of cells via a set of paths. The multiple secondary windings further balance the set of cells based on the charging currents. A ratio between a first turn number of a first secondary winding of the secondary windings and a second turn number of a second secondary winding of the secondary windings is determined by a nominal voltage ratio between two corresponding cells of the set of cells.Type: GrantFiled: October 21, 2011Date of Patent: December 3, 2013Assignee: O2Micro, Inc.Inventors: William Densham, Constantin Bucur, Flavius Lupu, Jiun Heng Goh, Stefan Maireanu
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Publication number: 20130019037Abstract: A battery management chip may include a battery management unit and a vertical bus circuit. The battery management unit can monitor a cell status of multiple cells in a battery module coupled to the battery management chip in response to an instruction from a host processor. The vertical bus circuit may transfer the instruction from the host processor to the battery management unit. The vertical bus circuit may include a first receiver, a command processor and a first transmitter. The first receiver can receive a first pair of differential input data signals. The command processor can process the first pair of differential input data signals. The first transmitter can output a first pair of differential output data signals.Type: ApplicationFiled: July 15, 2011Publication date: January 17, 2013Inventors: Allan Flippin, William Densham, Jiun Heng Goh, Constantin Bucur, Flavius Lupu, Stefan Maireanu
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Patent number: 8294421Abstract: A cell balancing circuit for balancing battery cells includes a transformer and a switching controller. The transformer has a primary winding and a secondary winding. The switching controller can select a first cell coupled to the primary winding and select a second cell coupled to the secondary winding. The first cell and the second cell are coupled in series. The first cell has a cell voltage that is greater than the second cell. The cell balancing circuit further includes a controller coupled to the primary winding. The controller controls energy from the first cell to the primary winding so as to transfer the energy from the first cell to the second cell to balance the battery cells.Type: GrantFiled: September 2, 2009Date of Patent: October 23, 2012Assignee: O2Micro IncInventors: Constantin Bucur, Stefan Maireanu
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Publication number: 20120081126Abstract: A battery monitoring system for a battery including multiple battery cells is disclosed. The battery monitoring system includes multiple first switch sets coupled across the battery cells respectively, an energy storage element, and a comparator coupled to the energy storage element via a second switch set. The energy storage element samples cell voltages of the battery cells via the first switch sets respectively. The comparator compares a respective cell voltage with a first reference signal to determine whether a fault condition occurs on a respective battery cell. The second switch set and one of the first switch sets are turned on alternately.Type: ApplicationFiled: September 30, 2010Publication date: April 5, 2012Inventors: Stefan MAIREANU, William DENSHAM, Jiun Heng GOH, Flavius LUPU, Constantin BUCUR
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Patent number: 8148942Abstract: In a power converter, a primary winding receives an input power. In addition, multiple secondary windings transform the input power into multiple charging currents to charge a set of cells via a set of paths. The multiple secondary windings further balance the set of cells based on the charging currents. A ratio between a first turn number of a first secondary winding of the secondary windings and a second turn number of a second secondary winding of the secondary windings is determined by a nominal voltage ratio between two corresponding cells of the set of cells.Type: GrantFiled: November 5, 2009Date of Patent: April 3, 2012Assignee: O2Micro International LimitedInventors: William Densham, Constantin Bucur, Flavius Lupu, Jiun Heng Goh, Stefan Maireanu
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Publication number: 20120038323Abstract: In a power converter, a primary winding receives an input power. In addition, multiple secondary windings transform the input power into multiple charging currents to charge a set of cells via a set of paths. The multiple secondary windings further balance the set of cells based on the charging currents. A ratio between a first turn number of a first secondary winding of the secondary windings and a second turn number of a second secondary winding of the secondary windings is determined by a nominal voltage ratio between two corresponding cells of the set of cells.Type: ApplicationFiled: October 21, 2011Publication date: February 16, 2012Inventors: William DENSHAM, Constantin BUCUR, Flavius LUPU, Jiun Heng GOH, Stefan MAIREANU
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Patent number: 7977911Abstract: A power supply system can include a primary power supply coupled to an output, and a secondary power supply coupled to the output. The primary power supply provides power to the output when a voltage level of the secondary power supply is less than a first predetermined level. The secondary power supply provides power to the output when the voltage level of the secondary power supply is greater than the first predetermined level. The secondary power supply not only provides power to the output, but also charges the primary power supply when the voltage level of the secondary power supply is greater than a second predetermined level that is greater than the first predetermined level.Type: GrantFiled: October 1, 2007Date of Patent: July 12, 2011Assignee: O2 Micro, Inc.Inventors: Stefan Maireanu, Alex Hartular, Chun Lu, Jianping Xu, Xinhe Su, Xiaodong Wang
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Publication number: 20110101916Abstract: In a power converter, a primary winding receives an input power. In addition, multiple secondary windings transform the input power into multiple charging currents to charge a set of cells via a set of paths. The multiple secondary windings further balance the set of cells based on the charging currents. A ratio between a first turn number of a first secondary winding of the secondary windings and a second turn number of a second secondary winding of the secondary windings is determined by a nominal voltage ratio between two corresponding cells of the set of cells.Type: ApplicationFiled: November 5, 2009Publication date: May 5, 2011Inventors: William DENSHAM, Constantin BUCUR, Flavius LUPU, Jiun Heng GOH, Stefan MAIREANU
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Patent number: 7804278Abstract: In one embodiment, a battery management system includes a charger controller for controlling a charging current of a battery according to a status of a load which is powered by the battery, and a counter coupled to the charger controller for determining a charging time according to such status. Advantageously, a first charging current is selected when the load is off. A second charging current that is less than the first charging current is selected when the load is on. Furthermore, a frequency of the counter is set to a first frequency when the load is off. The frequency is set to a second frequency that is less than the first frequency when the load is on.Type: GrantFiled: July 25, 2007Date of Patent: September 28, 2010Assignee: O2Micro International Ltd.Inventors: Stefan Maireanu, Chun Lu, Jianping Xu, Xiaohua Lei, Zhitong Lei, Yongqiang Yu
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Publication number: 20100225275Abstract: A cell balancing circuit for balancing battery cells includes a transformer and a switching controller. The transformer has a primary winding and a secondary winding. The switching controller can select a first cell coupled to the primary winding and select a second cell coupled to the secondary winding. The first cell and the second cell are coupled in series. The first cell has a cell voltage that is greater than the second cell. The cell balancing circuit further includes a controller coupled to the primary winding. The controller controls energy from the first cell to the primary winding so as to transfer the energy from the first cell to the second cell to balance the battery cells.Type: ApplicationFiled: September 2, 2009Publication date: September 9, 2010Inventors: Constantin Bucur, Stefan Maireanu
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Patent number: 7737662Abstract: A power system for managing charging, discharging and protection of rechargeable batteries is disclosed. The power system mainly includes a power system. The power system includes a switching circuit coupled to the rechargeable batteries to charge and discharge the rechargeable batteries. The power system includes a power management unit to control the switching circuit. The power system includes a temperature sensing circuit to monitor a temperature of the batteries, voltage detectors to monitor voltages of the batteries, and current detectors to monitor a current of the batteries. If an abnormal condition is sensed by the power management unit when the power system is in an operating mode, the power management unit will terminate the operating mode by switching off the switching circuit to protect the batteries and the power system.Type: GrantFiled: December 26, 2006Date of Patent: June 15, 2010Assignee: O2Micro International Ltd.Inventors: Chun Lu, Stefan Maireanu, Luyang Luo, Lin Tang, Mingzhi He, Jianping Xu
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Patent number: 7531989Abstract: The present invention is a battery fuel gauge circuit for measuring the capacity of a battery pack. The battery fuel gauge circuit includes an amplifier circuit, a correction circuit, a plurality of comparators, and a multiplexer. The amplifier circuit can sense a discharge current flowing through a sense resistor and a variable temperature from the battery pack and generate a first and a second voltage signals, which are corrected by the correction circuit and compared with a reference voltage by the plurality of comparators. After correction and comparison, the multiplexer can transmit the compared signals to an external indicating circuit that controls the display of the capacity of the battery pack.Type: GrantFiled: May 9, 2006Date of Patent: May 12, 2009Assignee: 02Micro International Ltd.Inventor: Stefan Maireanu
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Publication number: 20080197812Abstract: In one embodiment, a battery management system includes a charger controller for controlling a charging current of a battery according to a status of a load which is powered by the battery, and a counter coupled to the charger controller for determining a charging time according to such status. Advantageously, a first charging current is selected when the load is off. A second charging current that is less than the first charging current is selected when the load is on. Furthermore, a frequency of the counter is set to a first frequency when the load is off. The frequency is set to a second frequency that is less than the first frequency when the load is on.Type: ApplicationFiled: July 25, 2007Publication date: August 21, 2008Inventors: Stefan Maireanu, Chun Lu, Jianping Xu, Xiaohua Lei, Zhitong Lei, Yongqiang Yu
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Publication number: 20080191557Abstract: A power supply system can include a primary power supply coupled to an output, and a secondary power supply coupled to the output. The primary power supply provides power to the output when a voltage level of the secondary power supply is less than a first predetermined level. The secondary power supply provides power to the output when the voltage level of the secondary power supply is greater than the first predetermined level. The secondary power supply not only provides power to the output, but also charges the primary power supply when the voltage level of the secondary power supply is greater than a second predetermined level that is greater than the first predetermined level.Type: ApplicationFiled: October 1, 2007Publication date: August 14, 2008Applicant: O2Micro Inc.Inventors: Stefan Maireanu, Alex Hartular, Chun Lu, Jianping Xu, Xinhe Su, Xiaodong Wang
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Publication number: 20080150488Abstract: A power system for managing charging, discharging and protection of rechargeable batteries is disclosed. The power system mainly includes a power system. The power system includes a switching circuit coupled to the rechargeable batteries to charge and discharge the rechargeable batteries. The power system includes a power management unit to control the switching circuit. The power system includes a temperature sensing circuit to monitor a temperature of the batteries, voltage detectors to monitor voltages of the batteries, and current detectors to monitor a current of the batteries. If an abnormal condition is sensed by the power management unit when the power system is in an operating mode, the power management unit will terminate the operating mode by switching off the switching circuit to protect the batteries and the power system.Type: ApplicationFiled: December 26, 2006Publication date: June 26, 2008Inventors: Chun Lu, Stefan Maireanu, Luyang Luo, Lin Tang, Mingzhi He, Jianping Xu