Abstract: A bipolar output charge pump circuit having a network of switching paths for selectively connecting an input node and a reference node for connection to an input voltage, a first pair of output nodes and a second pair of output nodes, and two pairs of flying capacitor nodes, and a controller for controlling the switching of the network of switching paths. The controller is operable to control the network of switching paths when in use with two flying capacitors connected to the two pairs of flying capacitor nodes, to provide a first bipolar output voltage at the first pair of output nodes and a second bipolar output voltage at the second pair of bipolar output nodes.

Abstract: A method of modelling speech of a user of a headset comprising a microphone, the method comprising: receiving a first sample, from a bone-conduction sensor, representing bone-conducted speech of the user; obtaining a measure of fundamental frequency of the bone-conducted speech in each of a plurality of speech frames of the first sample; obtaining a first distribution of the fundamental frequencies of the bone-conducted speech over the plurality of speech frames; receiving, from the microphone, a second sample; determining a first acoustic condition at the headset based on the second signal; performing a biometric process based on the first distribution of fundamental frequencies and the first acoustic condition.

Abstract: Calibrating devices communicating on the shared bus can assist in reducing conflicts on the bus and the resulting loss of data. For example, the timing of transmission of data from one device to another device on the shared bus may be adjusted to compensate for delays on the shared bus. For example, the transmitting device may adjust transmission to an earlier time than the programmed time by an amount proportional to a known delay, such that the signal arrives at a receiving device at the programmed time. When the adjustment is not able to obtain a desired alignment or would cause conflicts on the shared data bus, the timing may be adjusted to delay the transmission, rather than advance the transmission, such that the adjusted transmission time results in the receipt of the signal at the receiving device in an unused time window after the programmed time.

Abstract: A power delivery system may include a power converter configured to electrically couple to a power source and further configured to supply electrical energy to one or more loads electrically coupled to an output of the power converter and control circuitry configured to determine whether a voltage node in the power delivery system has fallen below a warning threshold voltage, determine whether the voltage node has fallen below a critical threshold voltage, wherein the critical threshold voltage is lesser than the warning threshold voltage, in response to a voltage of the voltage node falling below the warning threshold voltage, decrease a maximum current drawn by the power converter from a first current level to a second current level, and in response to a voltage of the voltage node falling below the critical threshold voltage, decrease a maximum current drawn by the power converter from the second current level to a third current level.

Abstract: A system may include a power converter having a maximum allowable input power drawn from a power source, an energy storage element coupled to an output of the power converter at a top plate of the energy storage element, wherein the energy storage element is configured to store excess energy, and control circuity configured to, when an input power of the power converter exceeds the maximum allowable input power, cause excess energy stored in the energy storage element to be consumed by circuitry coupled to the output of the power converter, and in order to maintain positive voltage headroom for the circuitry coupled to the output of the power converter, selectively couple a bottom plate of the energy storage element to the power source such that excess energy stored by the circuitry coupled to the output of the power converter is consumed from the energy storage device when the input power of the power converter exceeds the maximum allowable input power.

Abstract: This application relates to amplifier circuitry, in particular class-D amplifiers, operable in open-loop and closed-loop modes. An amplifier (300) has a forward signal path for receiving an input signal (SIN) and outputting an output signal (SOUT) and a feedback path operable to provide a feedback signal (SFB) from the output. A feedforward path provide a feedforward signal (SFF) from the input and a combiner (105) is operable to determine an error signal (?) based on a difference between the feedback signal and the feedforward signal. The feedforward comprises a compensation module (201) configured to apply a controlled transfer function to the feedforward signal in the closed-loop mode of operation, such that an overall transfer function for the amplifier is substantially the same in the closed-loop mode of operation and the open-loop mode of operation.

Abstract: Circuitry comprising: a capacitor; first circuitry; and second circuitry, wherein the circuitry is operable to couple the capacitor to the first circuitry when the first circuitry is active, and to couple the capacitor to the second circuitry when the first circuitry is inactive or is not actively using the capacitor.

Abstract: A system may include an electromagnetic load capable of generating a haptic event and a haptic processor configured to receive at least one first parameter indicative of a desired perception of the haptic event to a user of a device comprising the electromagnetic load, receive at least one second parameter indicative of one or more characteristics of the device, and process the at least one first parameter and the at least one second parameter to generate a driving signal to the electromagnetic load in order to produce the desired perception to the user despite variances in the device that cause an actual perception of the haptic event to vary from the desired perception.

Abstract: The present disclosure relates to switching drivers for driving a transducer. A switching driver (202) has supply nodes for receiving supply voltages (VSH, VSL) defining at least one input voltage and an output node (104). A controller (205) controls operation of the first switching driver to generate a drive signal for the transducer at the output node (104), based on an input signal (Sin). A first capacitor (201a) is connected between first and second capacitor nodes (104, 204a) and a second capacitor (201b) is connected between the second capacitor node (204a) and a third capacitor node (204b). A network of switches (203) selectively connects any of the driver output node, the second capacitor node and the third capacitor node to either of a respective pair of said supply nodes, with the first capacitor node connected to the first driver output node.

Abstract: A nonlinear control system and a speaker protection system are disclosed. In particular, a control system for adapting an audio output from a speaker in the proximity of an object is disclosed. The controller is configured to accept one or more input signals, and one or more estimated states produced by the model to produce one or more control signals. A speaker protection system and a quality control system are disclosed. More particularly, a system for clamping the input to a speaker dependent upon an estimate of the proximity, acoustic volume, and/or acoustic coupling of the speaker to a nearby object is disclosed.

Abstract: A semiconductor die may be coupled to a printed circuit board using a solder ball. The semiconductor die comprises a redistribution layer formed above a semiconductor chip, a polymer layer formed on the redistribution layer, and an Under Bump Metallurgy (UBM) layer formed on the polymer layer. The polymer layer comprises a plurality of vias, which electrically couple the UBM layer to the redistribution layer. The entire UBM layer may be deposited with a continuously flat upper surface for coupling to the solder ball. The plurality of vias may be positioned such that they are centered on a point that is not central to the UBM layer.

Abstract: This application relates to circuitry for monitoring for instability of an amplifier. The amplifier (100) has a first signal path between an amplifier input (INN) and an amplifier output (VOUT) and a feedback path from the output to form a feedback loop with at least part of the first signal path. A comparator (212) has a first input configured to receive a first signal (INN) derived from a first amplifier node which is part of said feedback loop and a second input configured to receive a second signal (INP) derived from a second amplifier node which varies with the signal at the amplifier input but does not form part of said feedback loop. The comparator is configured to compare the first signal to the second signal and generate a comparison signal (COMP), wherein in the event of amplifier instability the comparison signal comprises a characteristic indicative of amplifier instability.

Abstract: A system may include a plurality of actively-driven inductive sensors and a plurality of control circuits, each control circuit of the plurality of control circuits configured to control operation of a respective set of the actively-driven inductive sensors, each control circuit of the plurality of control circuits communicatively coupled to the other control circuits via a connection configured to distribute synchronization information among the plurality of control circuits. Each of the plurality of control circuits may further be configured to configure a schedule for controlling time-division multiplexed operation of its respective set of actively-driven inductive sensors and control time-division multiplexed operation of its respective set of actively-driven inductive sensors based on the schedule and the synchronization information in order to minimize interference among the plurality of actively-driven inductive sensors.

Abstract: This application relates to methods and apparatus for driving a transducer with switching drivers where the switching driver has an output bridge stage for switching an output node between switching voltages and a modulator for controlling the duty cycle of the output bridge stage based on an input signal. The switching driver also includes a voltage controller for providing the switching voltages which is operable to provide different switching voltages in different driver modes. A controller is provided to control the driver mode of operation and the duty cycle of the switching driver based on the input signal, and the controller is configured to transition from a present driver mode to a new driver mode by controlling the voltage controller to provide the switching voltages for the new mode and controlling the modulator to vary the duty cycle of the output bridge stage. The change in duty cycle is controlled such that there is no substantial discontinuity in switching ripple due to the mode transition.

Abstract: A host device configured to be wirelessly coupled to an accessory device, the host device comprising noise reduction circuitry, wherein, in use of the host device: a signal generated by a microphone of the accessory device in response to ambient noise is supplied to the noise reduction circuitry; the noise reduction circuitry applies a noise reduction transfer function to the signal supplied thereto to generate a noise cancellation signal; and the noise cancellation signal is supplied to at least one loudspeaker of the accessory device; and wherein the noise reduction transfer function applied by the noise reduction circuitry is user selectable or user adjustable.

Abstract: The present disclosure relates to circuitry for detecting at least partial removal of an audio accessory plug from a corresponding socket. The circuitry comprises a monitoring unit comprising a first terminal configured to be electrically connected to a first socket contact of the socket that is in electrical contact with a first plug contact of the plug when the plug is fully received in the socket. The monitoring unit is configured to monitor a first impedance of a first signal path coupled to the first terminal, and the circuitry is configured to output a signal indicative of detection of at least partial removal of the plug from the socket in response to detection by the monitoring unit of a first predetermined sequence of impedance states of the first signal path.

Abstract: A method of controlling a force sensor system to define at least one button implemented by at least one force sensor, the method comprising: receiving a force sensor input; determining a gradient of the force sensor input; and controlling the force sensor system based on the determined gradient.

Abstract: An analog-to-digital conversion system may include an analog-to-digital converter configured to convert an analog input signal into an equivalent digital input signal, a first filtering path configured to filter the equivalent digital input signal to generate a first filtered digital signal, wherein the first filtering path comprises a zero-overshoot monotonic step response filter, a second filtering path configured to filter the equivalent digital input signal to generate a second filtered digital signal, wherein the second filtering path comprises a frequency-selective filter; and a mixer configured to either: (i) select between the first filtered digital signal and the second filtered digital signal in order to generate an output digital signal; or (ii) combine selected proportions of each of the first filtered digital signal and the second filtered digital signal in order to generate the output digital signal.

Abstract: A speech signal is received by a device comprising first and second transducers, and the first transducer comprises a microphone. A method comprises performing a first voice biometric process on speech contained in a first part of a signal received by the microphone, in order to determine whether the speech is the speech of an enrolled user. A first correlation is determined, between said first part of the signal received by the microphone and a corresponding part of the signal received by the second transducer. A second correlation is determined, between said second part of the signal received by the microphone and the corresponding part of the signal received by the second transducer. It is then determined whether the first correlation and the second correlation satisfy a predetermined condition.

Abstract: A method for determining a direct current impedance of a transducer may include receiving an input signal indicative of an electrical power consumed by the transducer and calculating, by a thermal model of the transducer, the direct current impedance based on the electrical power.