Cirrus Logic Inc.

Sameer Baveja

Hamed Sadati

Rupesh Khare

Gary Robertson

This application relates to circuitry for monitoring for instability of an amplifier. The amplifier () has a first signal path between an amplifier input (IN) and an amplifier output (V) and a feedback path from the output to form a feedback loop with at least part of the first signal path. A comparator () has a first input configured to receive a first signal (IN) derived from a first amplifier node which is part of said feedback loop and a second input configured to receive a second signal (IN) 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.

Amplifier circuitry

This application relates to methods and apparatus for voltage control, and in particular to maintain safe voltages for components of audio driving circuits that are operable in a high voltage mode. An audio driving circuit () may include a power supply module () and may be operable such that, in use, a voltage magnitude at a source terminal of at least a first transistor () of the audio driving circuit can exceed its gate-source voltage tolerance. A voltage generator (P) is configured to output a first intermediate voltage (V) to an intermediate voltage path for use as a gate control voltage for at least the first transistor, to maintain its gate-source voltage below tolerance. An intermediate path voltage clamp (P) is provided for selectively clamping the intermediate voltage path to a voltage level, so as to maintain the magnitude of the gate-source voltage of the first transistor below tolerance. The voltage clamp (P) is enabled by a reset condition (RST) for the audio driving circuit.

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Edinburgh, United Kingdom

Sameer Baveja