Abstract: Reduced delay and improved threshold tracking over PVT in a comparator input circuit and comparator are provided by circuits that include an inverter stage having a first complementary pair of transistors connected in a push-pull configuration. An input of the inverter stage is coupled to the gates of the first complementary pair of transistors, and an output of the inverter is coupled to the drains of the first complementary pair of transistors. The circuits also include one or more first degeneration transistors coupled between a source of one of the first complementary pair of transistors and a power supply rail of the circuit, and a reference circuit with an output coupled to one or more gates of the first degeneration transistors. The reference circuit controls the one or more first degeneration transistors to cause the inverter stage to have a threshold voltage equal to a threshold control voltage.

Abstract: Integrating ADC based sensing systems that convert the output of a measurement sensor to a digital value avoid conversion errors caused by sensor temperature variation during the conversion cycle. The systems may either include a primary integrating ADC and a residue ADC, and adjust rate of operation of the ADCs independently according to a sensed temperature of the measurement sensor, or the systems may differentiate an output of the residue ADC, and apply a temperature correction in accordance with the sensed temperature of the sensor to an output of the differentiator, integrate the temperature-corrected output of the differentiator and then combine the result with the output of the primary integrating ADC.

Abstract: A system and method provide on-line, wafer-level, die-level, or package-level thermal calibration of an integrated measurement resistor with a single temperature insertion. The system includes a measurement resistor integrated on a substrate with an unknown temperature coefficient and a temperature reference sensor thermally coupled to the measurement resistor. A measurement circuit measures an indication of a resistance of the measurement resistor. An electrically-controllable integrated heat source is operated by a controller to change a temperature of the measurement resistor and the temperature reference sensor and stores values of the resistance indication and the sensed temperature corresponding to multiple temperatures of the temperature of the measurement resistor and the temperature reference sensor.

Abstract: A power converter circuit provides stable operation over wide ranges of power source impedance supplying energy to the power converter circuit. The power converter circuit includes an input terminal for receiving energy from an external power source, and a switching converter circuit that receives an input current from the input terminal at an input terminal voltage level and produces an output current or voltage. The switching converter circuit receives a control variable that sets a level of the input current drawn from the input terminal. The power converter circuit also includes a control circuit that determines an indication of an impedance or a change in impedance between the external power source and the input terminal, and generates the control variable in conformity therewith, so that a voltage drop between the external power source and the input terminal is limited by adjustment of the control variable.

Abstract: A method implemented by a control circuit adaptively controls operating parameters of a switched-mode power supply to compensate for variation in circuit parameters of the switched-mode power supply, such as variation of: an inductance of an inductor, a capacitance of an output capacitor, and variation of a load capacitance coupled to an output of the switched-mode power supply. The control circuit includes a comparison circuit that determines whether or not an output voltage of the switched-mode power supply has exceeded an overshoot threshold, and a switching control circuit that has an input coupled to an output of the comparison circuit. The switching control circuit adaptively adjusts a control variable that controls one or more operational parameters of the switched-mode power supply in conformity with a relationship between a value of the output voltage and a value of the overshoot threshold in response to the output of the comparison circuit.

Abstract: Circuit techniques reduce or prevent audible artifacts in a Universal Audio Jack (UAJ) interface circuit, improving handling of mis-configuration/mis-attachment of devices. The interface includes at least one terminal for accepting an audio input signal or providing an audio line output signal coupled to an input or output of a first audio circuit. The first audio circuit operates from a low voltage domain and receives the audio input signal or provides the audio line output signal. A second circuit operates from a higher voltage domain and a switching circuit couples the at least one terminal to the second circuit. The output is slew-rate controlled to control a transition time of the output, so that audible artifacts in the audio input signal or the audio line output signal that could be generated by the switching circuit connecting the second circuit to the at least one terminal are avoided.

Abstract: An integrated circuit (IC), including multiple registers and functional units for performing operations of the integrated circuit, provides security of register accesses. A bus interface controller coupled to the registers provides read/write access from bus interface. The IC includes a state controller for managing multiple operational modes, and an access control manager coupled to the state controller and the bus interface controller that asserts a dynamic lock over the accesses to the registers according to a selected operating mode and one or more protected addresses of the addressable register space corresponding to the current operating mode. A data screener compares data associated with the read or write accesses to sets of valid or invalid data values for the current operating mode and the protected addresses, and the access control manager permits or denies the read or write accesses in conformity with a result of the comparison.

Abstract: Noise cancellation operations consume battery power, and thus techniques for reducing power consumption by performing power management in active noise cancellation in consumer devices are beneficial for the user. One example power management technique described according to embodiments of this disclosure allow wind noise detection to switch between a high-power higher-accuracy operation and a low-power lower-accuracy operation. For example, multiple microphones may be available on the personal device for detecting wind noise, in which using multiple microphones increases accuracy but also increases battery consumption. A personal device may switch between using a single microphone and multiple microphones based on environmental conditions to provide improved performance in certain environmental conditions and reduced power consumption in other environmental conditions.

Abstract: An integrated circuit (IC) substrate manufacturing process provides time-dependent device characteristic variation due to hydrogen absorption by including one or more gettering layers near the devices that would otherwise absorb hydrogen and exhibit the variation as the hydrogen migrates in the devices. The method includes forming or mounting the devices on a top surface of the semiconductor wafer in die areas of the substrate, forming semiconductor structures in the semiconductor die areas, forming a getter layer above or adjacent to the devices in the die areas, and processing the wafer with one or more processes exposing the wafer to vapor having a hydrogen content, whereby an amount of hydrogen absorbed by the devices is reduced by presence of the getter layer. The method produces wafers including semiconductor dies with reduced hydrogen absorption by the devices and packaged ICs including the dies.

Abstract: Techniques for reducing electromagnetic interference (EMI) in a switching amplifier circuit, control edge-rate with reduced sensitivity to process and temperature variations and that is reduced with increasing power supply voltage. The techniques control current levels in a pre-driver stage that drives an output driver of a switching amplifier circuit, according to a bias control. A first slope of a variation of the bias control with respect to a power supply voltage of the switching amplifier circuit over a first portion of a range of variation of the power supply voltage has a direction opposite a second slope of the variation of the reference output current with respect to the power supply voltage over a second portion of the range of variation of the power supply voltage. The resulting operation reduces electromagnetic interference generated by the driver over the second portion of the range of variation of the power supply voltage.

Abstract: The impedance of a connector, such as a flex cable, between a source and load affects the temperature and power consumption within an electronic system, such as a mobile device. According to embodiments described in this disclosure, the impedance of the flex cable may be separately tracked from the impedance of the source, which provides for improved power management within the electronic system. The impedance of the flex cable may be factored into determining a maximum available power to the load. The impedance of the flex cable may also be mapped to a temperature and used to manage power to maintain operation within temperature limits. Additional aspects of power management and impedance tracking for a connector are described herein.

Abstract: A differential amplifier provides improved signal swing and reduced common-mode output noise. The differential amplifier circuit includes a driver circuit with a first output for driving a first output of the differential amplifier and with a second output for driving a second output of the differential amplifier. The driver circuit has inputs for receiving a differential (complementary) pair of input signals at least one common-mode reference input for receiving a common-mode reference signal. The differential amplifier also includes a signal maxima detector having inputs for receiving the differential input signals that detects a maximum value between the individual signals, including any input common-mode voltage.

Abstract: A thin-film resistor circuit for an integrated circuit provides low resistance by segmenting a thin-film resistor to provide a wider effective thin-film resistor in a smaller die. The die includes a substrate, multiple electronic devices integrated on the substrate and interconnected to form at least a portion of an electronic circuit, a plurality of interconnect lands arranged in a grid that interconnect the devices with external terminals, and a thin-film resistor implemented by two or more thin-film resistor segments that operate in parallel in the circuit. The segments are disposed between different pairs of adjacent columns of the grid interconnect lands, with one of the thin-film resistor segments electrically connected along its width to lands of a first column of the grid of interconnect lands, and another one of the thin-film resistor segments is electrically connected along its width to lands of a second column of the grid interconnect lands.

Abstract: A cascaded switched power converter provides a wide voltage conversion ratio and improved efficiency ins systems such as power supplies and amplifiers. A switched-capacitor charge pump circuit is operated by one or more first clock signals and is coupled in cascade with an inductor-based power supply circuit according to one or more second clock signals. A control circuit that generates clock signals so that the one or more second clock signals have a phase offset with respect to the one or more first clock signals that is set to adjust a conversion ratio of the cascaded combination of the switched-capacitor charge pump circuit and the inductor-based power supply circuit. The inductor of the inductor-based power supply circuit may be an inductive load, such as a speaker, and the phase offset may be modulated according to an audio signal to provide audio amplification.

Abstract: This disclosure provides techniques for determining a reference resistance of a loudspeaker, such as in a mobile device. The reference resistance value may be used, among other applications, for speaker protection by reducing overdrive of the loudspeaker beyond safe temperature, which could damage the loudspeaker, while allowing driving of the loudspeaker closer to safety limits to improve performance of the loudspeaker. In a first aspect, a method of audio device monitoring includes applying a first signal to a loudspeaker; measuring a voltage and a current for the loudspeaker while applying the first signal to the loudspeaker; and determining a reference resistance for the loudspeaker based on the voltage and the current. Other aspects and features are also claimed and described.

Abstract: An adaptive noise-canceling system generates an anti-noise signal with a filter that has a response controlled by a set of coefficients selected from a collection of coefficient sets. The adaptive noise-canceling system includes an acoustic output transducer for reproducing a signal containing the anti-noise signal, a first microphone for measuring ambient noise at a first location to produce a first noise measurement signal, a second microphone for measuring the ambient noise at a second location to generate a second noise measurement signal, and an analysis subsystem for analyzing the first noise measurement signal and the second noise measurement signal. The adaptive noise-canceling system also includes a controller that selects the set of coefficients from the collection of coefficient sets according to a phase difference between the first noise measurement signal and the second noise measurement signal as determined by the analysis subsystem.

Abstract: A method implemented by a control circuit reduces electromagnetic interference (EMI) generation in a switched-mode power supply. The power supply adjusts operating frequency in response to a change in operating condition, and the method avoids certain bands of frequencies, for which switching should be avoided to avoid generating EMI in the band(s). The method includes determining a disallowed cycle time period range corresponding to the band(s) of frequencies by detecting that a switching event for the adjusted operating frequency would cause a switching cycle period to be within the disallowed time period range, and in response, preventing switching of the switched-mode power supply that would cause an end of a switching cycle to occur within the disallowed cycle time period range, and permitting switching of the switched-mode power supply that would cause the end of the switching cycle to occur outside of the disallowed cycle time period range.

Abstract: Methods and systems for determining clock signals for audio processing using different operating modes are provided. In one aspect, a transition control word is determined to transition from a first control word for a first operating mode to a second control word for the second operating mode. The transition control word may be used to process the received audio signal while transitioning between the operating modes. After the transition, the second control word may be used to process the received audio signal using the second operating mode. The transition control word may be used to transition between various aspects of the operating modes, including different frequencies or resolutions, control systems, power levels, and more.

Abstract: A circuit and method for generating a protection voltage includes a pair of voltage-generating circuits that generate voltages from the power supply voltage. The voltages have a differing dependence on the power supply voltage so that a difference between the first voltage and the second voltage changes sign for a particular value of the power supply voltage. The voltages are supplied to a protection voltage generating circuit that includes a pair of amplifiers having inputs that receive a respective one of the voltages and each of the amplifiers provides negative feedback to the other. An output circuit generates the protection voltage according to a maximum or a minimum value among the amplifier outputs, so that the protection voltage is monotonic with respect to variation of the power supply voltage.

Abstract: A method for constructing a solenoid inductor of an IC package with active/passive devices includes positioning an inner winding substantially around a magnetic core, positioning an outer winding substantially around the inner winding, and using a layered process to perform positioning the inner and outer windings. The layered process includes processing a first conducting layer as a bottom layer of the outer winding, above processing a first dielectric layer, above processing a second conducting layer as a bottom layer of the inner winding, above processing a second dielectric layer, above processing a magnetic core layer, above processing a third dielectric layer, above processing a third conducting layer as a top layer of the inner winding, above processing a fourth dielectric layer, above processing a fourth conducting layer as a top layer of the outer winding, above processing a fifth dielectric layer, and the inner and outer windings are electrically connected.