Stable distortion amplifier for audio signals
OwnerGerard Perrotinventor
Life of this patent
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Abstract
The invention relates to an amplifier for audio signals comprising a first (A.sub.1) and a second (A.sub.2) stage having a global feedback loop (B) between the output of the second stage and the input of the first stage, the second stage having a local feedback loop (B.sub.2) between its output and its input. Each feedback loop has a comparator element (C.sub.1). The amplifier comprises a means preventing the offset voltage present at the output of the first stage (A.sub.1) from being reinjected as input by feedback (in particular via the amplifier output). The local feedback loop (B.sub.2) is such that the second stage (A.sub.2) receives feedback at least continuously. The low frequency interference signals produced in the second stage (A.sub.2) are reduced by the feedback of the second stage (A.sub.2).
Claims10
A transistor amplifier for audio signals comprising a first stage and a second stage having a global feedback loop between the output of the second stage which output constitutes the output of the amplifier and the input of the first stage, the second stage also having a local feedback loop between its output and its input, the output of said first stage being connected to the input of said second stage and the first stage having no local DC feedback between its output and its input, characterized by the fact that said amplifier further comprises means for preventing the offset voltage present at the output of the first stage from being reinjected into the input of said first stage via said global feedback loop, and by the fact that the local feedback loop is such that the second stage receives feedback at least for continuous output signals in such a manner that low frequency interference signals generated in the second stage are reduced by the feedback of the second stage, which stabilizes its output operation point.
Dependencies are inferred from the claim text.