Cirrus Logic Inc.

Terence Orr

Mark McCloy-Stevens

Andrew Buist

Dave Smith

Paulius Cerebiejus

Saurabh Kumar Singh

Saurabh Singh

The present disclosure relates to current control circuitry for controlling a current through a load, the current control circuitry comprising: amplifier circuitry; reference voltage generator circuitry configured to supply a fixed reference voltage to a first input of the amplifier circuitry; an output stage comprising: a control terminal coupled to an output of the amplifier circuitry; a current input terminal configured to be coupled to the load; a current output terminal; a clock-controlled variable resistance coupled to the current output terminal of the output stage, wherein a resistance of the variable resistance is based on a digital code input to the variable resistance; and a feedback path between the current output terminal of the output stage and a second terminal of the amplifier circuitry for providing a feedback voltage to a second input of the amplifier circuitry.

Current control circuitry

The present disclosure relates to current control circuitry for controlling a current through a load. The current control circuitry comprises amplifier circuitry, reference voltage generator circuitry configured to supply a fixed reference voltage to a first input of the amplifier circuitry and an output stage comprising: a control terminal coupled to an output of the amplifier circuitry; a current input terminal configured to be coupled to the load; and a current output terminal. The current control circuitry further comprises a variable resistance coupled to the current output terminal of the output stage, and a feedback path between the current output terminal of the output stage and a second terminal of the amplifier circuitry for providing a feedback voltage to a second input of the amplifier circuitry.

This application relates to amplifier circuits for amplifying an audio signal. An amplifier circuit () has a voltage regulator () for outputting a supply voltage to an amplifier (). An output capacitor () coupled to an output node of the voltage regulator. The voltage regulator is operable in a voltage-control mode to maintain the output voltage (V) at a nominal output voltage and in current-control mode to limit the input current drawn to exceed a defined limit. A controller () is operable in a first mode to define the nominal output voltage so as not to exceed a first voltage magnitude and in a second mode to define the nominal output voltage to be equal to a second, higher, voltage magnitude. The controller () monitors the audio signal for a high-amplitude part of the audio signal, that could result in the voltage regulator operating in the current-control mode to apply current limiting and, on such detection swaps from the first to the second mode until such a high-amplitude part of the audio signal has been amplified. The second voltage magnitude is greater than required for voltage headroom for amplifying the high-amplitude part of the audio signal so as to allow for a voltage droop of the output voltage over a plurality of switching cycles of the voltage regulator when operating in the current-control mode.

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Edinburgh, United Kingdom

Terence Orr