Automatic calibration of Time to Digital Converter

Due to its restricted usage and accuracy in measuring extremely short interval of time, TDC (time to digital converter) embedded measurement devices are relatively expansive. Even if new applications are being developed in daily life as well as in industry, the cost condition of TDC based measurement systems needs to be improved. To reduce the deployment cost on a commercial scale, analogue interpolation method is preferred to digital interpolation method for most of TDCs. However, the analogue interpolation method does not provide robustness to temperature variation and non-uniformity of parts, which results in difficulty in maintaining the expected repeatability. In this paper, an auto-calibration method is proposed for robust operation and precise measurement of TDC under the condition of temperature variation and lack of parts uniformity.