US Patent 7508180 Switching regulator for fixing a frequency

A switching regulator includes a power stage, an output capacitor, a first reference voltage generator, a comparator, a constant-time trigger, a frequency-to-voltage converter, and an error amplifier. The power stage includes a first switch, a second switch coupled to the first switch, and an output inductor. The comparator is coupled to the output capacitor, and output inductor, and the first reference voltage generator. The constant-time trigger is coupled to the comparator and the power stage. The error amplifier includes a first input end coupled to the frequency-to-voltage converter, a second input end, and an output end coupled to the constant-time trigger.