Cirrus Logic Inc.

Eric Walburger

John L Melanson

Johann Guy Gaboriau

Xiaofan Fei

Jason Powell Rhode

Wilson E Taylor, Jr

Steven Green

A thermal sensor at the output of a switching amplifier senses heat dissipation at the output switch. If an overheating condition is sensed, gain of the digital input signal is lowered to reduce output power of the audio output signal.

Thermal feedback for switch mode amplification

An apparatus and method for limiting the output current in a switched mode amplifier are implemented. The apparatus includes a driver amplifier configurable for selective operation in one of three modes. The amplifier is operable for transitioning between the first mode and one of the second and third modes in response to a state of an output node of the driver. Bias circuitry, configurable for selective coupling to the driver amplifier is operable for limiting the output current of the amplifier in the first operating mode.

Circuits and methods for slew rate control and current limiting in switch-mode systems

A system for suppressing transient noise in switched-mode amplifier systems is disclosed. An amplifier, for amplifying a signal from a digital signal source includes a first complementary metal oxide semiconductor field effect transistor (MOSFET) pair. A common node of the pair is serially coupled to an output node of the amplifier by a resistor. The first MOSFET pair is configured to drive a ramp on the output node of the amplifier.

Transient noise reduction circuits, systems and methods in power digital-to-analog converters

An output stage includes a first output switch 201 having a current path for driving an output from a first voltage rail and a second output switch having a current path for selectively driving the output from a second voltage rail. A first reference switch is scaled with respects to first output switch and has a current path coupled to the first voltage rail. A second reference switch scaled with respects to second output switch has a current path coupled to a current path of first reference switch at a node and the second voltage rail. The logic measures an impedance mismatch between first and second reference switches and proportionally varies the impedance of a selected one of first and second output switches in response.

Circuits and methods for output impedance matching in switched mode circuits

An apparatus and method for power digital-to-analog converter protection are implemented. An attenuation value is set in response to the value of the supply voltage. The attenuation value is provided to a gain control, along with the input signal. A gain, offset by the attenuation value, determines the gain-adjusted output signal of the gain control generated from the input signal.

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Austin, TX, United States of America

Eric Walburger