A Level Shifter for CMRR-Enhanced Biopotential Acquisition Systems with Human-Body-Coupled Floating Supply Domain

A new level shifter (LS) is presented for logic voltage translation from human-body-coupled floating supply domain (HBCF-SD) to normal fixed supply domain (NF-SD). The LS utilizes diode-connected loads in the latch to deal with the HBCF supply and employs a preamplification stage to increase tolerable input common-mode voltage (ICMV) range significantly with high energy efficiency. The LS is designed in 0.18-μm process to convert the signal with a swing of 0.45 to 1 V in the HBCF-SD to the signal with a swing of 1.8 V in the NF-SD. The post-layout simulation results show that the LS operates properly even with a 1-V
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variation of the ICMV and maintains consistent performance.