Research On Key Techenologies Of Low Power Instrumentation Amplifier

For chronic diseases,the monitoring of wearable medical devices is very effective and timely,so more and more attention has been paid on it,and the key module affecting wearable medical devices is the performance of analog front-end instrumentation amplifiers.Therefore,the analog front end should be carefully designed to meet the signal characteristics of the bioelectrical signal.Its input impedance and common mode rejection ratio should be relatively high,and the power consumption should be relatively low.At present,the input impedance of most designs is limited,and the effects of common mode rejection ratio and suppression electrode mismatch are relatively general.Since the AC-coupled instrumentation amplifier does not use a chopper,it does not introduce current noise,and the power consumption of ACIA is also low,which satisfies the design requirements of this paper.However,the AC-coupled instrumentation amplifier has the problem of low-frequency flicker noise introduced by high-impedance negative feedback resistors and the structure's input impedance is low.In order to improve the input impedance to improve the common-mode rejection ratio of the circuit,and improve the ability of obtaining signals from electrodes,this paper proposes an AC-coupled instrumentation amplifier with on-chip self-calibration technology for the input impedance of the instrumentation amplifier.After completing the analysis of the transfer function,design of the on-chip self-calibration algorithm,the analysis of the input impedance and the analysis of difficult parts in the instrumentation amplifier,the on-chip self-calibration technique was designed.And the IA is completed under the 0.18?m process.The power supply voltage of the AC-Coupled Instrumentation Amplifier?ACIA?is 1.2 V and the supply current of the core transconductance amplifier is 1.2?A.The input impedance of the designed instrumentation amplifier is greater than 14 G?,and the power consumption is 1.44?W.The input the integral noise over a signal bandwidth of 0.3 Hz to 3 kHz is 4.1?V_rms,and the input the integral noise over a wider signal bandwidth of 0.3 Hz to 3 kHz is 6.4?V_rms,the NEF of ACIA is 5.42,and the common-mode rejection ratio of ACIA is 96 dB.