The invention concerns a circuit for speech recognition comprising: a voice detection circuit configured to detect, based on at least one input parameter, the presence of a voice signal in an input audio signal and to generate an activation signal on each voice detection event; a speech recognition circuit configured to be activated by the activation signal and to perform speech recognition on the input audio signal, the speech recognition circuit being further configured to generate an output signal indicating, based on the speech recognition, whether each voice detection event is true or false; and an analysis circuit configured to generate, based on the output signal of the speech recognition circuit, a control signal for modifying one or more of said input parameters.