Simple and high-sensitive resistance-to-time converter using current-mode Schmitt triggers

Abstract

A simple and high-sensitive resistance-to-time converter is presented for interfacing resistive bridge sensors. It consists of a resistive half bridge, two current-mode Schmitt triggers, a ramp voltage integrator, and two logic gates. HSPICE simulation results with KEC CMOS 0.5µm process exhibit a conversion sensitivity amounting to 5218.3µs/Ω over the resistance deviation range of 0-2Ω, and its linearity error is less than ±0.0005%. The temperature stability of the converter is less than 320ppm/°C in the temperature range of -25-85°C.