Class D audio amplifier

Abstract

A class D amplifier (1) comprises an input unit (11) for receiving a digital input signal (Vin), a pulse shaping unit (12) for producing pulse shaped signals in dependence of the input signal (Vin), a comparator unit (13) for comparing the pulse shaped signals and producing a comparator signal, a driver unit (14) for producing driver signals in dependence of the comparator signal, a switching output unit (15) for producing a pulse width modulated output signal (Vout) in dependence of the driver signals, and a feedback unit (16) for feeding the output signal (Vout) back to the pulse shaping unit (12). The input unit (11) comprises a clipping control unit (10) for controlling the duty cycle of the pulse width modulated output signal (Vout).

Description

technical field [0001] This invention relates to audio amplifiers. More specifically, the present invention relates to class D amplifiers capable of producing pulse width modulated output signals. Background technique [0002] In a class D amplifier, the output stage is used as a switch for switching the output signal between positive and negative supply voltages depending on the input signal. The resulting output signal is therefore a pulse width modulated bipolar signal, which can be demodulated by a demodulation filter and then made audible by a loudspeaker. [0003] Switching of the output stage typically turns one of a pair of output transistors on and the other off. When one of the output transistors is off, it draws zero current and therefore dissipates zero power, resulting in high efficiency and relatively low power and cooling requirements. [0004] Class D amplifiers are usually configured with an integral analog feedback loop to reduce any distortion introduce...

AI Technical Summary

Problems solved by technology

Also, this prior art solution effectively causes the output to change its sign, but still allows the integrator to run away, so it only provides a partial solution to the problem

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