Patent application number | Description | Published |
20090128826 | HIGH RESOLUTION IOC DRIVE AND METHOD FOR DRIVING FIBER OPTIC GYROSCOPES - Methods and system are provided for driving light through a sensing coil of an optical gyro. The system includes a photodetection circuit having an input for receiving an optical output from the sensing coil and having an output, and a signal processing circuit having an input coupled to the output of the photodetection circuit and having an output for supplying an output signal to modulate the sensing coil. The photodetection system produces a digital signal from the optical output. The signal processing circuit produces a feedback signal from the digital signal and adds a random number to the feedback signal to produce the output signal. | 05-21-2009 |
20090256528 | DIFFUSION-LIMITED ADAPTIVE BATTERY CHARGING - Some embodiments of the present invention provide a system that adaptively charges a battery, wherein the battery is a lithium-ion battery which includes a transport-limiting electrode governed by diffusion, an electrolyte separator and a non-transport-limiting electrode. During operation, the system determines a lithium surface concentration at an interface between the transport-limiting electrode and the electrolyte separator based on a diffusion time for lithium in the transport-limiting electrode. Next, the system calculates a charging current or a charging voltage for the battery based on the determined lithium surface concentration. Finally, the system applies the charging current or the charging voltage to the battery. | 10-15-2009 |
20090259420 | ADAPTIVE SURFACE CONCENTRATION BATTERY CHARGING - Some embodiments of the present invention provide a system that adaptively charges a battery, wherein the battery is a lithium-ion battery which includes a transport-limiting electrode, an electrolyte separator and a non-transport-limiting electrode. To charge the battery, the system first determines a lithium surface concentration at an interface between the transport-limiting electrode and the electrolyte separator. Next, the system uses the determined lithium surface concentration to control a charging process for the battery so that the charging process maintains the lithium surface concentration within set limits. | 10-15-2009 |
20090273320 | CONTROLLING BATTERY CHARGING BASED ON CURRENT, VOLTAGE AND TEMPERATURE - Some embodiments of the present invention provide a system that charges a lithium-ion battery. During operation, the system monitors: a current through the battery, a voltage of the battery, and a temperature of the battery. Next, the system uses the monitored current, voltage and temperature to control a charging process for the battery. In some embodiments, controlling the charging process involves: inferring electrode lithium surface concentrations for the battery from the monitored current, voltage and temperature; and applying the charging current and/or the charging voltage in a manner that maintains the inferred electrode lithium surface concentrations for the battery within set limits. | 11-05-2009 |
20090325056 | PARALLEL BATTERY ARCHITECTURE WITH SHARED BIDIRECTIONAL CONVERTER - Some embodiments provide a system that provides a power source. The power source includes a set of cells and a main power bus configured to connect the set of cells in a parallel configuration. The power source also includes a bidirectional converter configured to connect to one cell from the set of cells at a time. Finally, the power source includes a set of switches configured to switch each cell in the set of cells to one of the main power bus and the bidirectional converter. | 12-31-2009 |
20100308770 | METHOD AND SYSTEM FOR CHARGING A SERIES BATTERY - Some embodiments of the present invention provide a system for charging a series battery, wherein the series battery is comprised of a set of banks which are connected in series, so that the same charging current passes through each bank. During the charging process, the system measures a voltage across each bank in the set of banks. The system then compares the measured voltage with a target voltage for each bank, and adjusts the charging process based on results of the comparisons between the measured voltage and the target voltage. | 12-09-2010 |
20110031957 | CONTROLLING POWER LOSS IN A SWITCHED-CAPACITOR POWER CONVERTER - The disclosed embodiments relate to a system that implements a switched-capacitor power converter which is configured to actively control power loss while converting an input voltage to an output voltage. This system includes one or more switched-capacitor blocks (SCBs), wherein each SCB includes a first capacitor and a set of switching devices configured to couple a constant-potential terminal and a time-varying-potential terminal of the first capacitor between the input voltage, the output voltage and a reference voltage. The system also includes a clocking circuit which produces gate drive signals for switching transistors in the one or more SCBs. The system additionally includes a controller configured to actively control the gate drive signals from the clocking circuit to substantially minimize the power loss for the switched-capacitor power converter. | 02-10-2011 |
20120153728 | BALANCING VOLTAGES BETWEEN BATTERY BANKS - A system that balances voltages between battery banks. The system includes battery banks, including a first bank and a second bank, and a first capacitor. The system also includes a first set of switching devices which selectively couple first and second terminals of the first capacitor to first and second terminals of the first bank, and to first and second terminals of the second bank. The system includes a clocking circuit which generates clock signals with substantially non-overlapping first and second clock phases. This clocking circuit is configured so that during the first phase the first and second terminals of the first capacitor are coupled to the first and second terminals of the first bank, respectively, and during the second phase the first and second terminals of the first capacitor are coupled to the first and second terminals of the second bank, respectively. | 06-21-2012 |
20120153898 | METHOD AND SYSTEM FOR CHARGING A SERIES BATTERY - Some embodiments of the present invention provide a system for charging a series battery, wherein the series battery is comprised of a set of banks which are connected in series, so that the same charging current passes through each bank. During the charging process, the system measures a voltage across each bank in the set of banks. The system then compares the measured voltage with a target voltage for each bank, and adjusts the charging process based on results of the comparisons between the measured voltage and the target voltage. | 06-21-2012 |
20140077815 | METHOD AND APPARATUS FOR DETERMINING A CAPACITY OF A BATTERY - Some embodiments of the present invention provide a system that accurately and reliably updates a full charge capacity of a battery. During operation, the system charges the battery from an initial state to a rest point prior to reaching a fully charged state. The system then interrupts the charging process to allow the battery to relax to a resting voltage. Next, the system measures the resting voltage. The system then resumes the charging process toward the fully charged state. The system subsequently estimates the capacity of the battery based on the measured resting voltage and one or more other parameters. | 03-20-2014 |
20140079969 | ESTIMATING STATE OF CHARGE (SOC) AND UNCERTAINTY FROM RELAXING VOLTAGE MEASUREMENTS IN A BATTERY - Some embodiments of the present invention provide a system that estimates a state of charge for a battery. During operation, while the battery is relaxing toward a fully rested state, the system determines if a modified state of charge of the battery is substantially consistent with a predetermined decay pattern. If so, the system estimates the state of charge of the battery as a value of the modified state of charge determined at the time when the consistency is observed. Otherwise, the system continues monitoring the modified state of charge of the battery. In one embodiment, the predetermined decay pattern is a single exponential decay. After estimating the state of charge of the battery, the system may determine an uncertainty of the estimated state of charge. More specifically, the system can estimate the uncertainty as substantially equal to a fraction of the difference between the value of the modified state of charge and the value of the voltage-based state of charge at the time when the consistency is observed. | 03-20-2014 |
20140197805 | DIFFUSION-LIMITED ADAPTIVE BATTERY CHARGING - Some embodiments of the present invention provide a system that adaptively charges a battery, wherein the battery is a lithium-ion battery which includes a transport-limiting electrode governed by diffusion, an electrolyte separator and a non-transport-limiting electrode. During operation, the system determines a lithium surface concentration at an interface between the transport-limiting electrode and the electrolyte separator based on a diffusion time for lithium in the transport-limiting electrode. Next, the system calculates a charging current or a charging voltage for the battery based on the determined lithium surface concentration. Finally, the system applies the charging current or the charging voltage to the battery. | 07-17-2014 |
20140257724 | TRACKING FADING BATTERY CAPACITY IN A PLUGGED-IN PORTABLE ELECTRONIC DEVICE - A system for tracking the capacity of a battery in a portable electronic device is described. While the portable electronic device remains plugged in to a power adapter, the system estimates the capacity of the battery by performing the following operations. The system measures a first open-circuit voltage for the battery while the battery rests at a first state of charge. Next, the system causes the battery to transition to a second state of charge. While the battery transitions to the second state of charge, the system integrates a current through the battery to determine a net change in charge for the battery. Next, the system measures a second open-circuit voltage for the battery while the battery rests at the second state of charge. Finally, the system estimates a capacity for the battery based on the first open-circuit voltage, the second open-circuit voltage and the net change in charge. This capacity measurement is repeated and the multiple results are fit to a line. The slope of fitted line is then used to estimate how the true battery capacity has faded since last measured using traditional methods that require the battery to be rested at a low state of charge. | 09-11-2014 |
20140327410 | BATTERY CHARGER INTEGRATED CIRCUIT CHIP - An on-chip digital communication interface circuit is to be directly coupled to a counterpart interface circuit of a separate battery-side gas gauge circuit. An on-chip battery charging control circuit controls battery charging voltage and current that is supplied from a separate power source interface circuit to a battery cell terminal, according to charging voltage and current limits. The charging limits are read from the gas gauge circuit and in effect carry out a selected one of several different battery charging profiles. Other embodiments are also described and claimed. | 11-06-2014 |
20150022160 | ADAPTIVE EFFECTIVE C-RATE CHARGING OF BATTERIES - The disclosed embodiments provide a system that manages use of a battery in a portable electronic device. During operation, the system obtains a voltage of the battery and a state-of-charge of the battery. Next, the system calculates an effective C-rate of the battery using the voltage and the state-of-charge. Finally, the system uses the effective C-rate to manage a charging process for the battery. | 01-22-2015 |