Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method and system is disclosed for modifying the pulse width modulation signal frequency for controlling the backlight illumination intensity of a liquid crystal display. The modified pulse width modulation signal frequency is selected to eliminate visible light and dark bands in the liquid crystal display image. The brightness of the display may be also adjusted by modifying the duty cycle of the pulse width modulation signal. The brightness selected, either automatically or by the user, is matched with a pulse width modulation signal frequency to insure that the pulse width modulation signal will be anti-phased across a plurality of contiguous frame refresh periods.

Abstract: Methods and apparatuses for computing an absolute difference of two vectors of numbers. In one aspect of the invention, a method for execution by a microprocessor in response to receiving a single instruction includes: receiving a first plurality of numbers and a second plurality of numbers; and generating simultaneously a third plurality of numbers, each of which is an absolute difference between a number in the first plurality of numbers and a number in the second plurality of numbers. The above operations are performed in response to the microprocessor receiving the single instruction.

Abstract: Electronic devices such as portable electronic devices contain electronic components. The electronic components may include radio-frequency transceiver circuitry. The radio-frequency transceiver circuitry may be used for handling data communications and cellular telephone voice communications. One or more adjustable clock sources may be provided within the electronic device. The adjustable clock sources may be based on phase-locked-loop circuits. A clock manager may determine which frequencies are being used by the radio-frequency transceiver circuitry and other components in the electronic device. The clock manager may use this information to compute a list of safe fundamental clock signal frequencies. Based on the list of safe clock signal frequencies, the clock manager may dynamically adjust the clock sources to avoid collisions between harmonics of the clock signals from the clock sources and the frequencies used by the transceiver circuitry and other components.

Abstract: Methods and apparatuses to perform calibration of imprecise sensors for power monitoring in a data-processing system are described. The system includes a load coupled to one or more sensors. An electronic load changes a first input signal through one or more sensors by a predetermined amount. A difference in an output signal from the one or more sensors in response to the changing is obtained. The output signal is measured and sampled. A distribution of samples of the output signal is determined. The estimated parameters of the distribution that most likely to explain actual data are determined. Next, a transfer function of the one or more sensors is determined based on the estimated parameters. The input signal through the load is accurately predicted using the transfer function of the one or more sensors to monitor the power usage by the load.

Abstract: One embodiment of the present invention provides a system that switches between frame buffers which are used to refresh a display. During operation, the system refreshes the display from a first frame buffer which is located in a first memory. Upon receiving a request to switch frame buffers for the display, the system reconfigures data transfers to the display so that the display is refreshed from a second frame buffer which is located in a second memory.

Abstract: A system and method for reducing reflections in a transmission line and for recovering energy from the load in the transmission during the process. At least three drive signal levels are utilized. The transition from the second level to the third level during a rising transition and the transition from the second level to the first level during a falling transition is timed to coincide with the arrival of the reflected signal from the immediately-preceding transition. A capacitor is advantageously used as the source for the intermediate drive signal levels and advantageously facilitates energy recovery and conservation.

Abstract: Methods and apparatuses to perform calibration of imprecise sensors for power monitoring in a data-processing system are described. The system includes a load coupled to one or more sensors. An electronic load changes a first input signal through one or more sensors by a predetermined amount. A difference in an output signal from the one or more sensors in response to the changing is obtained. The output signal is measured and sampled. A distribution of samples of the output signal is determined. The estimated parameters of the distribution that most likely to explain actual data are determined. Next, a transfer function of the one or more sensors is determined based on the estimated parameters. The input signal through the load is accurately predicted using the transfer function of the one or more sensors to monitor the power usage by the load.

Abstract: A power source, a primary inductor, a load capacitance, and one or more tuned branch resonators and switching devices are coupled to generate pulses which represent a superposition of sinusoidal waveforms. The primary inductor is connected between the power source and the load. At the start of each cycle the load is coupled to ground and each tuned-branch resonators is reinitialized to re-energize the circuits and to stabilize the waveform when the frequencies of the sinusoidal waveforms are non-periodic.

Abstract: A power-supply circuit is described. In particular, the power-supply circuit includes an input node configured to receive a power-supply signal, an output node configured to output a modulated power-supply signal, and a modulation mechanism coupled between the input node and the output node. This modulation mechanism is configured to modulate the power-supply signal to produce the modulated power-supply signal. Furthermore, the modulation mechanism may be configured to modulate the power-supply signal using both a first modulation and a second modulation. This first modulation is a duty-cycle modulation which controls the power output of the piezoelectric transformer signal, and the second modulation spreads harmonic energy associated with the first modulation over a range of frequencies. By spreading the harmonic energy, the perceived acoustical noise generated by the piezoelectric transformer is reduced.

Abstract: A system that determines power consumption on an IC chip. The system includes a test structure located within the IC chip variations which includes one or more gates which receives power from a power source, wherein each gate has a different drive strength, and wherein the output of each gate is coupled to a load through a corresponding switch. The system also includes a current-measuring mechanism coupled to the power supply which measures the current consumed by the gates. When a specific switch is activated, the output of a corresponding gate is coupled to the load, thereby causing the corresponding gate to drive the load. The current consumed by the corresponding gate is measured by the current measuring mechanism. The measured current can be used to determine the power consumption of the corresponding gate driving the load.

Abstract: One embodiment of the present invention provides a system that facilitates changing a clock frequency in a memory system. During operation, the system receives a command to change the clock frequency to a new clock frequency. The system then iteratively changes the clock frequency to the new clock frequency. More specifically, the system starts an iteration by slewing the clock frequency toward the new clock frequency by an increment to reach an intermediate frequency without interfering with normal memory-system operation. Next, the system signals a memory controller to pause normal memory system operation by completing or cancelling all in-flight or outstanding memory system operations and not accepting additional memory operation requests.

Abstract: One embodiment of the present invention provides a system that facilitates selectively increasing the operating frequency of an electronic circuit, such as a computer system. The system begins by operating in a low-power state with the frequency and voltage of the electronic circuit set to low levels. Upon recognizing the need for performance beyond the low power level, the electronic circuit enters the first-intermediate power state. In this first-intermediate power state, the frequency and voltage are set to first-intermediate levels. Upon recognizing the need for performance beyond the first-intermediate power state, the electronic circuit enters the maximum-sustainable power state. In this power state, the frequency and voltage are set to maximum sustainable levels. Upon recognizing the need for performance beyond the maximum-sustainable power state, the electronic circuit temporarily enters a boosted power state beyond the maximum-sustainable power state.

Abstract: Methods and apparatuses to perform calibration of imprecise sensors for power monitoring in a data-processing system are described. The system includes a load coupled to one or more sensors. An electronic load changes a first input signal through one or more sensors by a predetermined amount. A difference in an output signal from the one or more sensors in response to the changing is obtained. The output signal is measured and sampled. A distribution of samples of the output signal is determined. The estimated parameters of the distribution that most likely to explain actual data are determined. Next, a transfer function of the one or more sensors is determined based on the estimated parameters. The input signal through the load is accurately predicted using the transfer function of the one or more sensors to monitor the power usage by the load.

Abstract: One embodiment of the present invention provides a system that switches from a first graphics processor to a second graphics processor to drive a display. During operation, the system receives a request to switch a signal source which drives the display from the first graphics processor to the second graphics processor. In response to the request, the system first configures the second graphics processor so that the second graphics processor is ready to drive the display. Next, the system switches the signal source that drives the display from the first graphics processor to the second graphics processor, thereby causing the second graphics processor to drive the display.

Abstract: A multiphase resonant pulse generator (74) has N groups of N?1 switches (44,46,48) which, when activated, form N paths from a power supply (Vdc) to ground or a reference voltage. Here N is a positive integer greater than 2. Each of the paths includes an inductance (38,40,42) and N?1 switches. The signal outputs (X1,X2,X3) from each of the N paths are cross coupled to switches belonging to the other N?1 paths to active or deactivate the groups of switches.

Abstract: A system and method for reducing reflections in a transmission line and for recovering energy from the load in the transmission during the process. At least three drive signal levels are utilized. The transition from the second level to the third level during a rising transition and the transition from the second level to the first level during a falling transition is timed to coincide with the arrival of the reflected signal from the immediately-preceding transition. A capacitor is advantageously used as the source for the intermediate drive signal levels and advantageously facilitates energy recovery and conservation.

Abstract: One embodiment of the present invention provides a system that facilitates selectively increasing the operating frequency of an electronic circuit, such as a computer system. The system begins by operating in a low-power state with the frequency and voltage of the electronic circuit set to low levels. Upon recognizing the need for performance beyond the low power level, the electronic circuit enters the first-intermediate power state. In this first-intermediate power state, the frequency and voltage are set to first-intermediate levels. Upon recognizing the need for performance beyond the first-intermediate power state, the electronic circuit enters the maximum-sustainable power state. In this power state, the frequency and voltage are set to maximum sustainable levels. Upon recognizing the need for performance beyond the maximum-sustainable power state, the electronic circuit temporarily enters a boosted power state beyond the maximum-sustainable power state.