Various example implementations are directed to circuits and methods for generating a clock signal. According to an example embodiment, a circuit arrangement includes a relaxation oscillator configured to output a clock signal. The clock signal has an oscillation frequency dependent on a reference current provided to the relaxation oscillator, an operating temperature of the relaxation oscillator, and a supply voltage used to power the relaxation oscillator. The circuit arrangement also includes a current source coupled to the relaxation oscillator and configured to generate the reference current. The current source is configured to adjust the reference current, in response to a change in one or more of the temperature of the relaxation oscillator and the supply voltage, to inhibit change in the oscillation frequency of the clock signal.