A relaxation oscillator includes a capacitor connected to a comparator input, current sources switched to supply power to the capacitor based on an output of the comparator, and a duplicate integrator shifting a voltage on the capacitor to offset a propagation delay through the comparator. The duplicate integrator includes current sources and a capacitor matching and switched in tandem with those within the relaxation oscillator, plus an additional current source, and is selectively switched into connection with the comparator input. By canceling the comparator propagation delay, the oscillator output frequency can be stably controlled through selection of resistive and capacitive values, using cheaper technology and tolerating large temperature, voltage and process variations.