Cirrus Logic Inc.

Texas Instruments Corporation

Cirrus Logic International Semiconductor Limited

Toru Ido

John Paul Lesso

Soichiro Ishizuka

Yanto Suryono

James Thomas Deas

Emmanuel Philippe Christian Hardy

Claire Motion

Naoki Furuya

Takeshi Anzai

Emmanuel Hardy

The present disclosure relates to driver circuitry for driving a piezoelectric transducer. The circuitry comprises: a power supply; a reservoir capacitance; switch network circuitry; and control circuitry. The control circuitry is configured to control operation of the switch network circuitry so as to charge the reservoir capacitance from the power supply and to transfer charge between the reservoir capacitance and the piezoelectric transducer.

Driver circuitry for piezoelectric transducers

Circuitry for determining an impedance of an electrochemical cell comprising at least one first electrode and a second electrode, the circuitry comprising: drive circuitry configured to apply a stimulus to the electrochemical cell; sense circuitry configured to measure a response of the electrochemical cell to the stimulus; and processing circuitry configured to: determine an estimated transfer function of the electrochemical cell based on the stimulus and the response; determine a score for the estimated transfer function; and adjust the stimulus or circuitry used to measure the response based on the score.

Electrochemical cell characterisation

Apparatus for delivering power from a battery node of a battery to an output node, the output node coupled to an analyte monitoring device, the apparatus comprising: a slow charging path between the battery node and the output node; a fast charging path parallel to the slow charging path, the fast charging path switchably coupled between the battery node and the output node; and control circuitry configured to: selectively couple the fast charging path between the battery node and the output node to allow faster transfer of charge between the battery node and the output node than the slow charging path.

Apparatus and methods for transferring charge

Circuitry for and methods of analyte measurement Circuitry for measuring a characteristic of an electrochemical cell, the circuitry comprising: a hysteretic comparator having a first comparator input, a second comparator input and a comparator output; a feedback path between the comparator output and the second comparator input configured to provide a feedback signal to the second comparator input; and a loop filter configured to apply filtering to the feedback path to generate the feedback signal, wherein the loop filter comprises the electrochemical cell.

Circuitry for analyte measurement

A method of cough detection in a headset, the method comprising: receiving a first signal from an external transducer of the headset; receiving a second signal from an in-ear transducer of the headset; and detecting a cough of a user of the headset based on the first and second signals.

Cough detection

A method of detecting live speech comprises: receiving a signal containing speech; obtaining a first component of the received signal in a first frequency band, wherein the first frequency band includes audio frequencies; and obtaining a second component of the received signal in a second frequency band higher than the first frequency band. Then, modulation of the first component of the received signal is detected; modulation of the second component of the received signal is detected; and the modulation of the first component of the received signal and the modulation of the second component of the received signal are compared. It may then be determined that the speech may not be live speech, if the modulation of the first component of the received signal differs from the modulation of the second component of the received signal.

Detection of live speech

The present disclosure relates to circuitry for driving a load. The circuitry comprises driver circuitry configured to generate a drive signal, based on an input signal to the driver circuitry, for driving the load, and commutator circuitry for coupling the driver circuitry to the load. The commutator circuitry is configured to alternate between commutation states in response to a level of the drive signal meeting a drive signal threshold or in response to a level of the input signal meeting a first input signal threshold. The circuitry is configured to apply an offset to the input signal when the input signal is below a second input signal threshold so as to increase a minimum level of the drive signal above the drive signal threshold or to increase a minimum level of the input signal above the first input signal threshold.

Driver circuitry

Circuitry for measuring a characteristic of an electrochemical cell, the circuitry comprising: a comparator having a first comparator input, a second comparator input and a comparator output; a feedback path between the comparator output and the second comparator input configured to provide a feedback signal to the second comparator input; and a loop filter configured to apply filtering to the feedback path to generate the feedback signal, wherein the loop filter comprises the electrochemical cell.

This application relates to Class D amplifier circuits. A modulator controls a Class D output stage based on a modulator input signal (Dm) to generate an output signal (Vout) which is representative of an input signal (Din). An error block, which may comprise an ADC, generates an error signal (&#x3b5;) from the output signal and the input signal. In various embodiments the extent to which the error signal (&#x3b5;) contributes to the modulator input signal (Dm) is variable based on an indication of the amplitude of the input signal (Din). The error signal may be received at a first input of a signal selector block. The input signal may be received at a second input of the signal selector block. The signal selector block may be operable in first and second modes of operation, wherein in the first mode the modulator input signal is based at least in part on the error signal; and in the second mode the modulator input signal is based on the digital input signal and is independent of the error signal. The error signal can be used to reduce distortion at high signal levels but is not used at low signal levels and so the noise floor at low signal levels does not depend on the component of the error block.

Class D amplifier circuit

The present disclosure relates to circuitry for driving a piezoelectric transducer based on an input signal. The circuitry comprises: primary driver circuitry configured to receive the input signal and to output a primary driving signal to the piezoelectric transducer based on the input signal; and secondary driver circuitry configured to receive an error signal indicative of an error between the input signal and the primary driving signal and to output a secondary driving signal to the piezoelectric transducer based on the error signal, wherein the primary driver circuitry and the secondary driver circuitry both comprise switching converter circuitry.

The present disclosure relates to Class D amplifier circuitry comprising a mode controller configured to dynamically adjust an operational switching mode of the Class D amplifier over a range between a Class AD mode and a Class BD mode.

Class D amplifiers

The present disclosure relates to circuitry for driving a piezoelectric transducer. The circuitry comprises amplifier circuitry configured to receive a drive signal and to output an output signal, based on the drive signal, to the piezoelectric transducer, a variable capacitor configured to be coupled in series with the piezoelectric transducer, and control circuitry. The control circuitry is configured to control a capacitance of the variable capacitor to compensate for hysteresis in the piezoelectric transducer and to control a gain of the amplifier circuitry to compensate for signal attenuation caused by the variable capacitor.

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Yokohama, Japan

Toru Ido