Time-to-Digital Converter for Ultrasonic Sensing Measurement of Water, Gas, Heat Flow Metering Applications using Time-of-Flight

The TDC7200 is a Time to Digital Converter (TDC) for ultrasonic sensing measurements such as water flow meter, gas flow meter, and heat flow meter. When paired with the TDC1000 (ultrasonic analog-front-end), the TDC7200 can be a part of a complete TI ultrasonic sensing solution that includes the MSP430, power, wireless, and source code.

The Time to Digital Converter (TDC) performs the function of a stopwatch and measures the elapsed time (time-of-flight or TOF) between a START pulse and up to five STOP pulses. The ability to measure from START to multiple STOPs gives users the flexibility to select which STOP pulse yields the best echo performance.

The device has an internal self-calibrated time base which compensates for drift over time and temperature. Self-calibration enables time-to-digital conversion accuracy in the order of picoseconds. This accuracy makes the TDC7200 ideal for flow meter applications, where zero and low flow measurements require high accuracy.

When placed in the Autonomous Multi-Cycle Averaging Mode, the TDC7200 can be optimized for low system power consumption, making it ideal for battery powered flow meters. In this mode, the host can go to sleep to save power, and it can wake up when interrupted by the TDC upon completion of the measurement sequence.