Application of class D power amplifiers in low power potentiostat circuits

Abstract

Summary In this paper a low power CMOS potentiostat is presented for energy limited applications such as human implantable sensors. The main focus is on using different techniques to reduce the power consumption at different circuit blocks, especially in the output stage that delivers power to the electrochemical cell. The proposed technique includes the use of a class D amplifier to reduce conduction power dissipation compared with conventional linear methods. Power dissipation has been improved by several other considerations such as elimination of opamp blocks which consume static power, avoiding current sampling stages and using dynamic latched comparators for loop error calculations. Closed loop stability problem and a low power solution to overcome this issue are addressed in the paper. The role of effective parameters such as inductor value, output MOSFET dimensions and clock pulse timing has been investigated and optimization considerations are used to achieve the low power potentiostat. Evaluation results show that a 12.96‐μW potentiostat with 1.03‐μW power dissipation and 89% efficiency is achievable with a linearity of R2 = 0.998. Copyright © 2016 John Wiley & Sons, Ltd.

The Class D Audio Power Amplifier: A Review

“…Paper [33] clearly illustrates the advantages and disadvantages: the first advantage of self-oscillation is eliminating the need for a low-jitter clock source, which is required for high-performance analog and digital input fixed-frequency amplifiers. Switching frequency is subsequently set by an oscillation condition and varies nonlinearly as a function of the input signal.…”