An integrated smart sensor for flow and temperature with I/sup 2/C bus interface: FTS2

A fully integrated smart sensor for flow and temperature has been realized. The sensor is able to communicate with a simple microcontroller using an I/sup 2/C serial data bus interface. The flow rate is obtained by determining the power needed to maintain a constant temperature difference above the flow temperature. The absolute temperature is measured using a bipolar PTAT circuit and a sigma-delta A-D converter. On-chip sensor settings can be programmed by the microcontroller. All digital processing needed to measure flow and temperature is realized on the chip.