A Universal Micro-Sensor Interface Chip with Network Communication Bus and Highly-Programmable

This paper presents a Universal Micro-Sensor Interface (UMSI) circuit designed for low-power microsystems that support multiple sensors and actuators. The interface chip contains all necessary reference, readout, control, and communication circuitry to interface a range of capacitive, resistive, voltage, or digital output devices to system control hardware. For online configuration of many parameters including readout gain and offset, this versatile chip is highly programmable through a sensor bus. The chip also incorporates a temperature sensor for compensation, an SPI interface, general purpose digital I/O, and an interrupt control unit for switch-type sensors. Fabricated in a foundry 3M 2P 0.5µm CMOS process, the die occupies 2.22mm x 2.22mm and draws 6.7 µΑ to 4 mA, (depending on configuration) from a 3V supply. Preliminary test results show the chip to be functional within design specifications. 1