Slide 1 Slide 2 Slide 3 Slide 4 Slide 5 Slide 6 Slide 7 Slide 8 Slide 9 Slide 10 Slide 11 Slide 12 Slide 13 Slide 14 Slide 15 Slide 16 Slide 17 Slide 18 Slide 19 Slide 20 Slide 21 Slide 22 Slide 23 Slide 24 Slide 25 Slide 26 Slide 27 Slide 28 Slide 29 Slide 30 Slide 31 Slide 32 Slide 33 Slide 34 Slide 35 Slide 36 Slide 37 Slide 38 Slide 39 Slide 40 Slide 41 Slide 42 Slide 43 Product List
DC-DC Conversion Cookbook Slide 14

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.

PTM Published on: 2013-04-11