Device and method for reducing clipping in an amplifier

摘要

Limiting clipping in an amplifier is accomplished in the feedback loop of a class D PWM amplifier that includes an integrator coupled to an input node and configured to generate an integrated input signal such that a comparator may then generate a PWM signal for driving an amplifier output stage based on a comparison to a triangle wave signal. To this end, the amplifier also includes a threshold signal generator for generating high and low voltage thresholds based on the triangle wave signal to be used to engage compensation circuits for limiting the overall amplification. Such compensation circuits may be bipolar junction transistors that are disposed in the feedback loop of the integrator. Thus, the overall bandwidth of the amplifier itself is not affected by adding a limiter circuit aimed at reducing clipping.

主权项

1. An amplifier circuit, comprising:
an input node configured to receive an input signal; an integrating amplifier having an integrating amplifier input coupled to the input node and having an integrating amplifier output configured to generate an integrating amplifier output signal; an integration feedback loop connecting the integrating amplifier output and the integrating amplifier input; and an analog limiter circuit coupled in parallel to the integration feedback loop between the integrating amplifier input and the integrating amplifier output and configured to variably bypass a current around the integration feedback loop in response to a voltage of the integrating amplifier output signal.