A modified version of 12-bit tracking analog to digital converter for high-stability output tracking

In this paper a 12-bit tracking analog-to-digital converter (ADC) is designed and its performance is verified. It continuously tests the analog input signal and makes correction when necessary. The resulting digital equivalent of the analog input signal is continuously updated. The least significant bit (LSB) of this converter jumps up and down to track the analog input. The digital output therefore permanently jumps between two subsequent bits, B_n and B_n+1. To overcome the problem of instability in the digital output the 12-bit tracking ADC is modified by introducing the test bit B ₀. The test bit is designed to have a voltage equals to that of the LSB. It always sets or resets in tracking the analog value. Using this technique the digital output B₁ to B₁₂ of the converter is maintained stable. Test and measurements are performed in the converter circuit to demonstrate the practicality of this version. ©2007 IEEE.