Anokiwave, Inc.

Eythan Familier

Kartik Sridharan

Scott R Humphreys

Gaurav Menon

Shamsun Nahar

Jun Li

Akhil Garlapati

Antonio Geremia

A time-to-digital converter (TDC) uses voltage as a representation of time offset. A voltage change is induced over a time period from a start signal to a stop signal. The final voltage is then measured, and the voltage measurement is mapped to a time value representing the time between the start signal and the stop signal. The voltage change can be increasing or decreasing, e.g., by charging or discharging a capacitive circuit between the start signal and the stop signal. The voltage can be measured using an analog-to-digital converter (ADC) or other voltage measurement circuit. The voltage measurement can be mapped to the time value in any manner, such as, for example, using a transfer function or using a mapping table that provides a time value for each possible voltage measurement value.

Time-to-digital converter using voltage as a representation of time offset

Digital post-processing of time-to-digital converter (TDC) output data can be used to map each TDC code to the ideal one, but this requires knowing the TDC input-output mapping. Therefore, a calibration system and method are provided for characterizing operation of a TDC to compensate for non-idealities. Input signals having a known time difference are provided to the TDC, and a mapping between the TDC output and the known time difference is stored in a mapping table. With the described method, it is possible to input an input ramp of very low slope to construct this mapping to a desired resolution during a background calibration procedure. This characterizing and mapping can be performed across a range of input signals having different known time differences. After calibration, a mapping table can be used by a mapping circuit of the TDC or by a digital post-processing function to provide a compensated TDC output.

Time-to-digital converter and calibration

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San Diego, CA, United States of America

Eythan Familier