A small-scale timer assembly includes a PWM signal generator including a selector for selecting one of a plurality of clock sources, a timer for counting based on the selected clock source to deliver an overflow signal, a comparator for comparing the count in the timer against a setting to deliver a coincidence signal, and a signal processor for generating a PWM signal based on the overflow signal and the coincidence signal, and a count controller for counting the number of overflow signals to allow the selector to select another of the clock sources. The PWM signal is used for generating a sinusoidal signal.