A 106dB PSRR direct battery connected reconfigurable class-AB/D speaker amplifier for hands-free/receiver 2-in-1 loudspeaker

A reconfigurable class-AB/D audio power amplifier for use with hands-free/receiver 2-in-1 loudspeaker is designed under direct battery connection for portable device application. With an on-chip battery voltage tracking common-mode reference generator (BAVTCMR) and pseudo-differential topology, 106 dB power supply rejection ratio (PSRR) can be achieved. This high PSRR attenuates the leak of power supply noise to the amplifier output and 100dB SNR can be achieved under maximum power GSM radio link. Reconfiguration is realized by integrator gain stage sharing and capacitor reuse technique to minimize hardware redundancy and simplify the design complexity. In a 0.153-μm CMOS technology, 76/74 dB THD can be achieved for class-AB and class-D, respectively. The active area of class-AB/D amplifier is 0.5mm².