An oscillator apparatus includes an oscillator circuit and a protection circuit. The oscillator circuit has an input and an output for generating a clock signal. The protection circuit is coupled to the input or the output of the oscillator circuit and is used for generating a second power switch control signal to the input of the oscillator circuit according to a signal edge of the clock signal and a first power switch control signal which is provided to the oscillator apparatus, to protect circuit element(s) included within the oscillator circuit.