Ultra Low-Power Low-Pass Filter Design for Wearable Biomedical Applications

Low-pass filter (LPF) is an important circuit block used in System on Chips (SoCs) for wearable biomedical applications. However, designing a LPF with low power consumption and negligible Process, Voltage and Temperature (PVT) dependency is a challenging task. We in this work report design of Complementary Source Follower (CSF)-C LPF which uses composite PMOS devices and Common Mode Bulk-feedback (CMBFB) for achieving ultra-low power operation. The proposed LPF circuit has been simulated in standard CMOS 0.18 μm process using BSIM3V3 models. The proposed LPF consume 0.064 nW power from 0.5 V voltage supply at supply current of 0.128 nA with dc gain of -3.6 dB, bandwidth of 200 Hz and Figure of Merit (FOM) of 0.004. The proposed LPF can be used in future low-voltage biomedical systems for achieving high power efficiency.