Cirrus Logic Inc.

Ian Johnson Smith

James Thomas Deas

Vivek Saraf

This application relates to transducer apparatus (), especially for MEMS capacitive transducers. The apparatus has a voltage bias generator () for receiving a supply voltage (V) and generating a bias voltage (V) for biasing a capacitive transducer (). A voltage supply path extends between a supply voltage input terminal () and the voltage bias generator (). A programmable trim circuit (), in use, controls the bias voltage generated by the voltage bias generator. A first filter () is configured to applying filtering to the voltage supply path. A programming contact pad () is configured to form an external contact of the transducer apparatus when packaged and is electrically coupled to the programmable trim circuit via a signal path that does not include the first filter.

Transducer apparatus and methods

The present disclosure relates to a protection system for protecting a MEMS transducer of a MEMS device from electrostatic capture, wherein the MEMS transducer is operable in a normal-sensitivity, mode and in a reduced-sensitivity mode. The protection system comprises: an overload detector for detecting an overload condition arising as a result of an excessive sound pressure level at the MEMS transducer; a signal estimator configured to generate an estimate of a sound pressure level at the MEMS transducer; and a controller configured, in response to detection by the overload detector of an overload condition, to: disable an output of the MEMS transducer; and after a delay of a first predetermined period of time: cause the MEMS transducer to operate in the reduced-sensitivity mode; enable the output of the MEMS transducer; and cause the MEMS transducer to return to the normal-sensitivity mode if the estimate of the sound pressure level generated by the signal estimator while the MEMS transducer is operating in the reduced-sensitivity mode is below a safe sound pressure level threshold for a second predetermined period of time.

MEMS devices

This application relates to methods and apparatus for configuring a serial data interface, especially a data interface () for a transducer () such as a digital microphone or loudspeaker. The data interface is selectively operable in a first or second serial data mode of operation for input of data to or output data from the transducer device. The first and second serial data modes are different, e.g. correspond to different serial formats. The data interface has a controller () configured to determine a resistance value () at a sense terminal () of the transducer device and to control the data interface in the first serial data mode if the resistance value is within a first resistance range and control the data interface in the second serial data mode if the resistance value is within a second, different, resistance range.

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Rosewell, United Kingdom

Ian Johnson Smith