Low power, low noise, 3-level, H-bridge output coding for hearing aid applications

摘要

A hearing aid (5) has a &Sgr;&Dgr; delta modulator (26) that receives an input data stream (18) and produces a &Sgr;&Dgr; modulated output data stream, having three states {+1,0,−1}. An H-bridge (28) receives the &Sgr;&Dgr; modulated output data stream and produces an output signal for delivery to an associated acoustic transducer (24). A circuit (30) is provided between the &Sgr;&Dgr; modulator (26) and the H-bridge (28) to force the &Sgr;&Dgr; modulated data stream to return to a zero state as part of each non-zero output period in the &Sgr;&Dgr; modulated data stream. A differential oscillator (34) having a differential oscillator output signal clocks a differential latch (32) to provide a differentially latched output to the H-bridge (28).