A Feedback Type Automatic Gain Controlnstrumentation Amplifier with A 10-bit Successivepproximation ADC
Date Issued
2009
Date
2009
Author(s)
Wang, Pei-Ye
Abstract
In recent years, with the scaling down of process, the concept of system on chip (SoC) can be realized. With the development if technology, people can control their health more detailed and complete, instantaneously and effectively. Due to the features of biomedical signals, which are usually ultra-low slevels, low speed and large noise. Therefore, we need an instrumentation amplifier to amplify the signal to proper scale for the following application. Since the requirement of biomedical application needs low power consumption, a successive approximation analog to digital converter is adopted in our implementation, which has the features of low speed, low power consumption and moderate accuracy. In the first part of this thesis, a 10-bit, low power, successive approximation is implemented. By using some techniques such as gating-clock, power switch and directly using supply voltage as reference voltage. The measurement results shows that while operating at 100KSPS, the maximum effective number of bits (ENOB) is higher than 8.7 bits. The measurements differential non-linearity (DNL) is between +0.6118/-1 LSB and the integral non-linearity (INL) is between +1.4431/-1.4425 LSB. The die area is 1.13mmx1.07mm fabricated in TSMC 0.35um CMOS 2P4M process. On the other hand, a feedback type automatic gain control instrumentation amplifier with a 10-bit successive approximation analog to digital converter is realized. In this implementation, while automatic gain control is on, the digital control unit of SAR ADC will produce feedback controlling signals to adjust the gain of programmable instrumentation amplifier (PGIA). This PGIA has eight kinds of gain, its open loop gain is 125db and phase margin is 76 degree. The die area is 1.25mmx1.36mm, which is implemented in TSMC 0.35um CMOS process with 3V supply voltage and the power consumption is 504uW.
Subjects
CMOS
SAR ADC
PGIA
AGC
Type
thesis
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