A bio-amplifier with pulse output

A low-power fully integrated bioamplifier is presented that can amplify signals in the range from mHz to kHz while rejecting large DC offsets generated at the electrode-tissue interface. The novel aspect of this amplifier is that its analog output is represented by a series of pulses which provide a low-power, noise-resistant means for coding and transmission. The original analog signal can be reconstructed from the resulting pulse train with 13 bit precision at a remote site where power consumption is not so crucial. The fabricated analog amplifier exhibits a gain of 39.5 dB from 0.3 Hz to 5.4k Hz. The power consumption of the whole system is less than 300 /spl mu/W/channel from a 5-V supply. The fully integrated system was designed in the AMI 0.6 /spl mu/m CMOS process and it consumes 0.088 mm/sup 2//channel of chip area.