Voltage-to-frequency converter with high sensitivity using all-MOS voltage window comparator

A CMOS voltage-to-frequency converter with output frequency range programmability

“…The main performances of the proposed voltage-tofrequency converter are summarized on Table I and compared with several previous CMOS realizations: [7], based on an negative feedback OTA as an input voltage to current converter stage and [10], a previously reported VFC by authors and based on a voltage follower configuration. The proposed VFC clearly exhibits a larger operating range, which almost covers the complete 0V DD full input range, with the possibility of choosing different output frequency ranges, while shows very competitive performances in terms of sensitivity, linearity and power consumption (less than 0.41mW).…”

“…In particular, this quasi-digital approach is, at present, taking a leading role in sensor signal interface circuits within embedded microcontroller systems. As a result, and focusing on CMOS technology seeking for the capability of cointegration of sensors and sensor electronics both analogue and digital at minimum cost and size, several CMOS fully integrated smart sensors with frequency or period [3][4][5][6] output signal, or simplest voltage-to-frequency converters that transform the conditioned output sensor voltage into frequency [7][8] have been proposed to date. This paper describes the design of a 1.8V-0.18µm CMOS VFC circuit with programmable output frequency ranges.…”