Abstract: An integrated sense resistor within an integrated circuit (IC) may be surroundingly positioned near and coupled to a connection such as a pin or ball. The integrated sense resistor may be shaped such that more surface area of the integrated sense resistor is coupled to be positioned closer or in actual contact with the pin or ball than conventional straight layered integrated sense resistor solutions. The integrated sense resistor may be a non-straight shape that entirely surrounds or wraps around a connection to the pin or ball, such as a circular or oval shape, a box or rectangular shape, a triangular shape, or a polygonal shape. The integrated sense resistor may be a non-straight shape that partially surrounds a connection to the pin or ball, such as an open-circular or semi-circular shape, an open-sided box or rectangular shape, an open-sided triangular shape, an angular shape, or an open curved shape.

Abstract: A controller of a boost converter may be configured to dynamically adjust conditions within the boost converter by monitoring conditions in the boost converter. For example, the controller may determine an current inductance value for an inductor of the boost converter by monitoring a current through the inductor. When the inductance value of the inductor is known, a slope compensation value may be used in determining a transition time between charging the inductor of the boost converter and discharging the inductor.

Abstract: During operation of a boost converter conditions may exist that result in a reverse current through the boost converter, such as when a load drop from the boost converter occurs. During the reverse current period, inductance value determinations made during a forward current period may be used to estimate a magnitude of the reverse current and this estimate used by a controller to control the boost converter and return the boost converter to normal operation. The controller may control the boost converter by changing a ratio of charging and discharging time for an inductor of the boost converter, decreasing a bandwidth of the boost converter, and/or increasing a resistance of the boost converter.

Abstract: An energy-efficient consumer device audio power output stage with gain control provides improved battery life and reduced power dissipation without clipping the audio output signal. A control circuit controls a power supply that supplies the power supply rails to the power amplified output stage. The voltage of the power supply rails is controlled in conformity with an input audio signal level, which may be determined from a volume control setting of the device and/or from a signal level detector that determines the amplitude of the signal being amplified. The gain applied to the audio input signal is reduced for a predetermined time period when a higher output voltage of the power supply is selected, to avoid clipping the audio output signal.

Abstract: An integrated sense resistor within an integrated circuit (IC) may be surroundingly positioned near and coupled to a connection such as a pin or ball. The integrated sense resistor may be shaped such that more surface area of the integrated sense resistor is coupled to be positioned closer or in actual contact with the pin or ball than conventional straight layered integrated sense resistor solutions. The integrated sense resistor may be a non-straight shape that entirely surrounds or wraps around a connection to the pin or ball, such as a circular or oval shape, a box or rectangular shape, a triangular shape, or a polygonal shape. The integrated sense resistor may be a non-straight shape that partially surrounds a connection to the pin or ball, such as an open-circular or semi-circular shape, an open-sided box or rectangular shape, an open-sided triangular shape, an angular shape, or an open curved shape.

Abstract: A DC servo loop may track DC offset changes of an input signal and apply feedback to amplifiers to adjust a DC offset of the input signal. The DC servo loop may include digital loop tracking and analog loop tracking components. The digital loop tracking components may track small changes in the DC offset. When the DC offset exceeds a certain threshold, analog loop tracking may be activated to apply feedback to the amplifiers to adjust the DC offset. The adjustments to the DC offset may be delayed until an amplitude of the input signal exceeds a threshold to reduce contribution to noise in the input signal.

Abstract: A circuit including headset type detection provides compatibility with different transducer types, such as headphones provided by different manufacturers. An audio circuit that generates or receives an audio signal includes electrical terminals for coupling to a transducer device, at least one of which carries the audio signal. A transducer device type detection circuit is included and detects a type of a transducer device coupled to the audio device from characteristics measured at the multiple electrical terminals when the transducer is coupled to the audio device. The circuit also includes a configuration control circuit for altering a configuration of the audio device according to a detected type of the transducer device.

Abstract: An energy-efficient consumer device audio power output stage with gain control provides improved battery life and reduced power dissipation without clipping the audio output signal. A power supply having a selectable operating mode supplies the power supply rails to the power amplified output stage. The operating mode is controlled in conformity with an input audio signal level, which may be determined from a volume control setting of the device and/or from a signal level detector that determines the amplitude of the signal being amplified. The gain applied to the audio input signal is reduced for a predetermined time period when a higher output voltage of the power supply is selected, to avoid clipping the audio output signal.

Abstract: A controller of a boost converter may be configured to dynamically adjust conditions within the boost converter by monitoring conditions in the boost converter. For example, the controller may determine an current inductance value for an inductor of the boost converter by monitoring a current through the inductor. When the inductance value of the inductor is known, a slope compensation value may be used in determining a transition time between charging the inductor of the boost converter and discharging the inductor.

Abstract: A circuit including headset type detection provides compatibility with different transducer types, such as headphones provided by different manufacturers. An audio circuit that generates or receives an audio signal includes electrical terminals for coupling to a transducer device, at least one of which carries the audio signal. A transducer device type detection circuit is included and detects a type of a transducer device coupled to the audio device from characteristics measured at the multiple electrical terminals when the transducer is coupled to the audio device. The circuit also includes a configuration control circuit for altering a configuration of the audio device according to a detected type of the transducer device.

Abstract: An offset correction circuit removes DC offset from an analog audio output signal by comparing transitions of digital audio values to which the analog output signal is related to the output of a monitor that monitors the analog output signal. The monitor may be a zero-crossing detector and the transitions of the digital signal that are compared may be transitions of the most-significant bit (MSB) of the digital audio values. A filtering algorithm or filter circuit may be used to average a result of the comparison of the transitions, so that the offset is slowly and accurately removed. A chopped or autozero comparator may be used to further reduce error in the offset determination.

Abstract: An integrated circuit audio processor having an internal-oscillator generated intermediate frequency reference provides for operation of an audio processor without requiring an external master clock. Input audio streams are sample-rate converted to an intermediate sample rate derived from the internal oscillator, which may be an LC oscillator. One or more output audio streams are generated from the one or more input audio streams at the intermediate sample rate and are converted from the intermediate sample rate to corresponding output sample rates. A divider generates the intermediate sample rate from the oscillator output, and is programmed to control the intermediate sample rate to ensure that the intermediate sample rate is in the proper range for operation of the integrated circuit. The divider can be programmed to accommodate changes in process, voltage and/or temperature of the IC, so that the intermediate sample rate is maintained near an expected frequency.

Abstract: A voltage reference circuit provides a precision voltage reference output without requiring a filter capacitor. The voltage reference output is generated by a digitally-controlled source, which has a value set by the output of a digital filter that filters the output of a comparison circuit that compares the voltage reference output to another reference. A selectable mode can be provided to provide a fast response during a startup/reset period and an optional hold or narrowband response after startup. The mode selection may also offer selection of an externally-supplied digital control value and/or a resistor divider type voltage reference as an alternative to the digitally-controlled source.

Abstract: An energy-efficient consumer device audio power output stage provides improved battery life and reduced power dissipation. A power supply having a selectable operating mode supplies the power supply rails to the power amplified output stage. The operating mode is controlled in conformity with the audio signal level, which may be determined from a volume control setting of the device and/or from a signal level detector that determines the amplitude of the signal being amplified. The power supply may be a charge pump in which the operating mode uses a capacitive divider to provide for selection of a power supply output voltage that is a rational fraction of the power supply output voltage in a full-voltage operating mode.

Abstract: A modulated gain audio control and zipper noise suppression techniques provide reduction in audible artifacts caused by discrete-valued gain changes. The gain of a signal is controlled by modulating between multiple gain values for corresponding time durations, so that a resulting average gain is controlled according to the average of the multiple gain values as weighted by their corresponding time durations. The modulation frequency is above the bandwidth of the signal. Transitions between gain levels are performed by changing the relative proportion of the durations to slowly change the gain according to a transition profile, which may be linear or non-linear. The modulation employed may be pulse-width modulation, or another modulation pattern such as a delta-sigma modulation pattern.

Abstract: A discrete time delta-sigma modulator circuit, which may be used to implement an analog-to-digital converter (ADC) provides improved anti-aliasing performance when lower quantization rates are selected, by maintaining the clocking rate of a first stage in the delta-sigma modulator loop filter at a rate higher than would ordinarily be selected for a lower quantization rate. To accomplish the anti-aliasing improvement, the ratio between the quantization rate and the clocking rate of the first integrator is reduced at the lower quantization rate, resulting in a first true alias image at a multiple of the quantization rate, permitting anti-aliasing filters to more effectively attenuate the alias image, and attenuating the images spaced at the quantization rate via the averaging operation of the first integrator.

Abstract: A method and apparatus for controlling a selectable voltage audio power output stage provides a mechanism for raising the selected power amplifier output voltage in time for the arrival of signal peaks to avoid clipping. Signal peaks may either be delayed by delaying an increase in volume control level or enabling signal compression for a predetermined time period, so that sufficient time is provided for the amplifier power supply to stabilize at a higher operating voltage when an increase of power supply voltage is selected. Alternatively, a signal level may be determined at an upstream source, such as a decoder or filter that provides information in sufficient advance of the arrival of the peaks, and used to control the power supply selection, so that the higher power supply voltage level is selected in advance of arrival of the signal peaks that would otherwise cause clipping at the power amplifier output.

Abstract: An integrated circuit audio processor having an internal-oscillator generated intermediate frequency reference provides for operation of an audio processor without requiring an external master clock. Input audio streams are sample-rate converted to an intermediate sample rate derived from the internal oscillator, which may be an LC oscillator. One or more output audio streams are generated from the one or more input audio streams at the intermediate sample rate and are converted from the intermediate sample rate to corresponding output sample rates. A divider generates the intermediate sample rate from the oscillator output, and is programmed to control the intermediate sample rate to ensure that the intermediate sample rate is in the proper range for operation of the integrated circuit. The divider can be programmed to accommodate changes in process, voltage and/or temperature of the IC, so that the intermediate sample rate is maintained near an expected frequency.

Abstract: A method and apparatus for controlling a selectable voltage audio power output stage provides a mechanism for raising the selected power amplifier output voltage in time for the arrival of signal peaks to avoid clipping. Signal peaks may either be delayed by delaying an increase in volume control level or enabling signal compression for a predetermined time period, so that sufficient time is provided for the amplifier power supply to stabilize at a higher operating voltage when an increase of power supply voltage is selected. Alternatively, a signal level may be determined at an upstream source, such as a decoder or filter that provides information in sufficient advance of the arrival of the peaks, and used to control the power supply selection, so that the higher power supply voltage level is selected in advance of arrival of the signal peaks that would otherwise cause clipping at the power amplifier output.

Abstract: An energy-efficient consumer device audio power output stage provides improved battery life and reduced power dissipation. A power supply having a selectable operating mode supplies the power supply rails to the power amplified output stage. The operating mode is controlled in conformity with the audio signal level, which may be determined from a volume control setting of the device and/or from a signal level detector that determines the amplitude of the signal being amplified. The power supply may be a charge pump in which the operating mode uses a capacitive divider to provide for selection of a power supply output voltage that is a rational fraction of the power supply output voltage in a full-voltage operating mode.