A low-cost VFC for low-power sensor interfaces

Widespread ubiquitous sensing systems require intensive research to develop low-cost sensor nodes maximizing energy efficiency. This paper presents the design and implementation of a CMOS voltage-to-frequency converter (VFC) part of a multi-sensor front-end signal conditioning system targeting wireless sensor networks applications. The proposed VFC, suitable to be directly interfaced to the microcontroller, is a cost-effective circuit, exhibiting at the same time high performance characteristics: designed in a 1.8 V-0.18 μm CMOS technology, operates with power consumption below 0.5 mW at output frequencies ranging from 0 to 2.0 MHz given a 0-1.6 V input with an error below 1 %.