Cirrus Logic Inc.

Wolfson Microelectronics Limited

John Bruce Bowlerwell

Andrew James Howlett

Alastair Mark Boomer

John Paul Lesso

David Paul Singleton

Yanto Suryono

Morgan Timothy Prior

Mark James Mccloy-Stevens

Xin Zhao

Willem Zwart

Holger Haiplik

Michael Page

John Anthony Breslin

Malcolm Blyth

Graeme S Angus

John Laurence Pennock

Pradeep Saminathan

Kathryn Rose Holland

Kapil Sharma

Andrew Buist

Peter Hsu

Sharjeel Riaz

Saurabh Singh

Andrei Dumitriu

Clive R Graham

Matthew Petherbridge

This application relates to methods and apparatus for sensing current in a monitored current path, where the monitored current path is bidirectional such that current can flow in either direction along the monitored current path. A current sensor has first and second sense resistors () configured to each pass a current corresponding to the current in the monitored current path. The first and second sense resistors are configured to have a matching arrangement, such that current flow through the first sense resistor when current is flowing in one direction in the monitored current path matches current flow through the second sense resistor when current is flowing in the opposite direction in the monitored current path.

Current sensing

An integrated circuit (IC), comprising: a converter comprising: one or more core devices; and one or more output internal nodes, each internal node coupled to one of the one or more core devices; protection circuitry comprising: one or more isolation switches, each of the one or more isolation switches coupled between a respective one of the one or more internal output nodes and a respective output external pin of the IC, wherein the protection circuitry configured to: monitor a characteristic at each respective external output pin of the IC; and if the characteristic is outside an operating specification of the one or more core devices, open one or more of the one or more isolation switches to isolate one or more of the one or more core devices from the respective external pin of the IC.

Protection circuitry

The present disclosure relates to circuitry comprising audio amplifier circuitry for receiving an audio signal to be amplified; and first and second output nodes for outputting first and second differential output signals. The circuitry further comprises common mode buffer circuitry configured to receive a common mode voltage and to selectively output the common mode voltage to the first and second output nodes.

Audio amplifier circuitry

The present disclosure relates to circuitry for providing an output voltage. The circuitry comprises: voltage generator circuitry configured to provide an output voltage to an output node of the circuitry; current limiter circuitry operable to perform current limiting so as to limit a current supplied at the output node of the circuitry; detection circuitry configured to output a detection signal when a load voltage across a load coupled to the output node of the circuitry reaches a target voltage; and delay circuitry configured to receive the detection signal and to output a control signal to deactivate current limiting by the current limiter circuitry after a predetermined delay period after receiving the detection signal.

Circuitry for providing an output voltage

Current detection circuitry for generating an average inductor current signal indicative of an average inductor current during an operational cycle of power converter circuitry, the current detection circuitry comprising: circuitry for generating a peak inductor current signal indicative of a peak inductor current during the operational cycle; and circuitry for applying a ripple current estimate signal, indicative of an estimate of half of a ripple current in the power converter circuitry, to the peak inductor current signal to generate the average inductor current signal, wherein the ripple current is equal to a difference between the average inductor current and the peak inductor current.

Current estimation in a power converter

Circuitry for estimating an inductance of an inductor in power converter circuitry, the circuitry comprising: circuitry for generating a peak inductor current signal indicative of a peak inductor current during an operational cycle of the power converter circuitry; circuitry for generating a ripple current estimate signal, indicative of an estimate of a ripple current in the power converter circuitry; and circuitry for applying the ripple current estimate signal to the peak inductor current signal to generate an average inductor current threshold signal indicative of an estimated average inductor current in the power converter circuitry during the operational cycle, wherein the ripple current estimate signal is based on: a duration of a charging phase of operation of the power converter circuitry; a voltage across the inductor; and an inductance value for the inductor; and wherein the circuitry for generating the ripple current estimate signal is operative to select an inductance value for the inductor for which the estimated average inductor current is equal to an actual average inductor current during the operational cycle to generate a value for the actual inductance of the inductor.

Estimation of an inductance in a power converter

This application relates to audio driving circuitry (), and in particular to audio driving circuitry for outputting first and second audio driving signals for driving a stereo audio load (), which may be a stereo audio load of an accessory apparatus () removably coupled to the audio driving circuitry in use. A load monitor () is provided for monitoring to monitor, from a monitoring node (), an indication of a common mode return current passing through a common return path, together with an indication of a common mode component of the first and second audio driving signals and to determine an impedance characteristic of the stereo audio load. The load monitor () can provide dynamic monitoring of any significant change in load impedance. In some embodiments the load monitor () comprises an adaptive filter () which adapts a parameter of the filter which is related to the load impedance so as to determine the indication of load impedance.

Load detection

The present disclosure relates to circuitry for detecting connection of a plug of an audio accessory device to a socket of an intermediate cable that is connected to a host device, wherein the plug of the accessory device is of a different type than the socket of the intermediate cable. 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; and a second terminal configured to be electrically connected to a second socket contact of the socket that is in electrical contact with a second plug contact of the plug when the plug is fully received in the socket. The monitoring unit is configured to: detect a first impedance of a first signal path from the first terminal; detect a second impedance of a second signal path from the first terminal; and detect a third impedance of a third signal path from the second terminal, wherein the circuitry is configured to output a signal indicative of detection of connection of the plug to the socket in response to detection by the monitoring unit that the detected first, second and third impedances do not correspond to expected first, second and third impedances.

Circuitry for detecting jack plug insertion or removal

The present invention relates to circuitry comprising: interpolation filter circuitry configured to receive a digital input signal and to output an interpolated digital signal; amplifier circuitry configured to generate an output signal based on the interpolated digital signal; and protection circuitry. The protection circuitry is configured to activate in response to detection of a fault condition at an output of the amplifier circuitry. The circuitry further comprises first detection circuitry configured to output a control signal to disable the protection circuitry on detection of a transient signal at an output of the interpolation filter circuitry that is unrelated to a fault.

The present disclosure relates to circuitry for selecting a bias voltage to output at a bias voltage output node of the circuitry. The circuitry comprises a first circuit node configured to receive a first voltage from a first, unregulated, voltage source and a second circuit node configured to receive a second voltage from a second, regulated, voltage source. A switch arrangement configured to selectively couple the bias voltage output node to the first circuit node or the second circuit node is also provided.

Biasing circuitry

This applications relates to methods and apparatus for monitoring a socket (), to detect a connection status of a mating plug (), e.g. for monitoring an audio jack socket for connection of an audio jack plug. A monitor () is configured to monitor a voltage (V) at a monitoring node (), which is coupled to a jack detect contact () of the socket and a voltage pull-up element (). The voltage (V) at the monitoring node () is monitored against a threshold (Vthv) and a threshold module () is configured to vary the threshold depending on an indication of signal activity (S) of a signal path for a first socket contact () which will be electrically connected to the jack detect contact when a plug when inserted in the socket.

Socket monitoring

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.

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Peterhead, United Kingdom

John Bruce Bowlerwell