Low power amplifier for biopotential signal acquisition system

In biomedical field there is a great need of VLSI in designing integrated bioamplifier circuits which performs the operation of amplifying low amplitude and low frequency signals. Due to excessive demand of implantable and wearable devices for processing biopotential signals, a low power bioamplifier is proposed in this paper and power dependency of bioamplifier on different current mirror configuration is discussed. In proposed bioamplifier architecture, cascode configured OTA(Operational Transconductance Amplifier) is used to increase the gain and lower the power consumption of the circuit. All transistors in OTA are operating in weak inversion region consuming nanoamperes of current. Proposed bioamplifier is designed using 180nm CMOS process technology with a supply voltage of 1.8 V. Simulated results shows, bioamplifier is operating with a low power dissipation of 6.25 uW, midband gain of 45.38 dB and passes signals in the frequency range of 5.02 Hz to 2.927 KHz.