AS6040 Ultrasonic Flow Converter
AS6040 is an ultrasonic flow converter (UFC) solution dedicated to gas meters, but suitable for water meters, too. The system is made of four major blocks: supervisor, frontend, post processing and interface. The supervisor manages all tasks and is the master of the whole system, making the AS6040 autonomous. The front-end integrates a high-voltage driver, an integrated PGA and an offset-stabilized comparator in the receive path, a precision TDC for the time-of-flight measurement, amplitude measurement as well as an RDC unit for temperature measurement. In flow meter mode, the 32-bit CPU in combination with 4k of ROM code and 4k of NVRAM does the post processing for flow calculation. In time conversion mode the CPU is not active and the chip sends the raw time-of-flight data. It communicates to an external microcontroller via SPI interface. By means of the integrated pulse interface the AS6040 can run also in stand-alone mode.