A Fast Bioimpedance Measurement Chip Design Using Dynamic Current

This paper proposes a method of IC design for fast bioimpedance measurement. The implemented chip comprises a current steering digital-to-analog converter (DAC), a voltage comparator, and a logic control module. The chip dynamically drives current into the impedance to be test, and the corresponding DAC code is read when the output voltage crosses the threshold the voltage comparator. The chip was designed and fabricated using SMIC 180-nm CMOS process. The results demonstrate that an impedance measurement range from
$\mathbf{200}\mathbf{\Omega}$
to
$\mathbf{80}\mathbf{k}\mathbf{\Omega}$
is achieved within
$\mathbf{10.2}\ \boldsymbol{\mu} \mathbf{s}$
under a clock at 100 MHz.