A temperature-compensated CMOS ring oscillator for DC-DC converters

A novel current controlled CMOS ring oscillator is presented in this paper. Specially circuit structure and transistor parameters design is used to obtain good temperature coefficient. The designed ring oscillator circuit has been used in a CMOS step-up switching regulator controller which has been implemented using a 0.5μm double poly double metal CMOS technology. The test result shows that the frequency is about 1.2MHz and the error (Δf/f) is about 3.5% in the temperature range 20–100°C. The circuit is quite suitable for DC-DC converters.