Shown on this slide is a comparison of two switching control techniques, pulse width modulation vs. pulse frequency modulation. In PWM the loop maintains a constant switching frequency and varies the duty cycle (TON) to control the output voltage. In a PFM type control, at light load, the converter is able to reduce the switching frequency thereby reducing switching losses and increasing efficiency. PFM is one of the techniques used to improve efficiency at light load, in addition to pulse skipping and burst mode. In pulse skipping the converter skips switching cycles when they are not needed, and in burst mode the converter switches producing short bursts; between pulses the converter shuts down almost completely, drastically reducing the average power consumption.