Cirrus Logic Inc.

Hamed Sadati

Sameer Baveja

John L Melanson

John Anthony Breslin

Sushanth Hegde

Rupesh Khare

Gary Robertson

Yu Tamura

Pre-conditioning circuitry for pre-conditioning a node of a circuit to support a change in operation of the circuit, wherein the circuit is operative to change a state of the node to effect the change in operation of the circuit, and wherein the pre-conditioning circuitry is configured to apply a voltage, current or charge directly to the node to reduce the magnitude of the change to the state of the node required by the circuit to achieve the change in operation of the circuit.

Pre-conditioning a node of a circuit

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.

Voltage control

A switching driver circuit may have an output stage having an output switch connected between a switching voltage node and an output node. A switch network may control a switching voltage at the switching voltage node so that in one mode the switching voltage node is coupled to a positive voltage and in another mode the switching voltage node is coupled to ground voltage via a first switching path of the switch network. The circuit may also include an n-well switching block operable to, when the first switching voltage node is coupled to a positive voltage, connect the n-well of the first output switch to the switching voltage node, and, when the first switching voltage node is coupled to the ground voltage, connect the n-well of the first output switch to a first ground which is separate to the first switching voltage node and independent of the first switching path.

Switching driver circuitry

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.

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Edinburgh, United Kingdom

Hamed Sadati