Low Voltage Biosignal Sensor ASIC Design

Biological signals can reflect the internal information of the human body,through the detection of biological signals can help doctors diagnose the patient's health?EEG has good temporal and spatial resolutions,it can be monitored for long time and continuously collected information.But traditional medical equipment can not monitore it for a long time.So miniaturization,portable biosensor's research and application has become a hot spot.In this paper,A bio-sensor be designed for for integrated circuit technology and it be used to the detection of EEG signals.The main design module have a low-power pre-amplifier and 12 bit SAR ADC.The pre-amplifier uses chopper stabilization technology to reduce the effect of 1/f noise,because EEG signal has different amplitude,so programmable gain amplifier is used for main amplifier.In order to reduce the chip area and the power loss caused by switching.DAC use a split capacitor array structure in the SAR ADC.At the same time,the automatic calibrationcircuit is added to eliminate the precision loss caused by parasitic capacitance and capacitance error.The circuit of this paper adopts CMOS 0.13 ?m technology,the power supply voltage is 1.2V.The pre-amplifier can effectively eliminate the 1/f noise by using chopper stabilization technique,its gain is 40dB-100dB,the phase margin is 54.7 degrees,and the-3dB bandwidth is 542 kHz,and the power consumption is 93.6?W.The 12 bit SAR ADC selection power 26 ?W selection,the processing speed is 15KS/s.After the calibration,the INL error is decreased from 6LSB to 0.25LSB.The core part of the chip area is 0.52*0.4mm2,the design of the whole circuit can satisfy the applications in portable equipment battery the power supply.