A power adaptive variable gain instrumentation amplifier for electrical impedance tomography

In this paper, we present an instrumentation amplifier for electrical impedance tomography. The instrumentation amplifier is designed to process a wide dynamic range input, based on a fast automatic gain control technique that minimizes measurement latency. In addition, the instrumentation amplifier employs a reconfigurable power scheme that allows it to adjust its total power consumption depending on the frequency of the input signal as well as on the phase of the measurement cycle. Results from a 3.3 V, 180 nm CMOS process simulation show that the proposed instrumentation amplifier can process signals up to 6 MHz, with an amplitude of 2 Vpp. The instrumentation amplifier maintains an SNR > 50 dB down to input amplitudes of 1.07 mV, and it has an average power consumption of 698 //W (<; 500 kHz operation) and 5.97 mW (> 500 kHz operation).