Ring Oscillator Based CMOS Temperature Sensor Design

This paper presents the ring oscillator based temperature sensor. The method is highly area efficient, simple and easy for IC implementation as compared to traditional temperature sensors. The proposed temperature sensor was fabricated using 0.35 μm technology, which occupies extremely small silicon area. It exploits the frequency of the ring oscillator that is proportional to temperature, which is displayed in the form of a digital output. The proposed temperature sensor comprises a ring oscillator, a voltage level shifter, a 10-bit counter, and a 10-bit register. The designed ring oscillator is frequency-tunable and the voltage level shifter provides the output to full-scale to make sure that the number of its rising edge is counted by the counter. The register saves the counted output.