Snubbers lossless

Lossless snubbers and aetive elamps produee PWM waveforms with soft edges. 

Figure 4-5 Lossless snubber for a one-transistor forward or flyback converter.

In boost eonverters the lossless snubber shown in Figure 4-6 ean be used. 

The disadvantage of the quasi-resonant converter compared to the newer lossless snubber and active clamp techniques in addition to the basic PWM converters, is the voltage or current stresses placed upon the power components. The peak voltage or current values that exist within quasi-resonant converters can be two to three times higher than in PWM converters. This forces the designer to use higher-rated power switches and rectifiers which may not have as good conduction characteristics. 

The following design examples eontain various teehniques to improve the overall effieieney of eommon designs. Most of the designs of aetive elamps and lossless snubbers are empirieal, so they are not ineluded within these design examples. 

Ben-Yaakov, Sam and Gregoiy Ivensky, Passive Lossless Snubbers for High Frequency PWM Converters, Seminar 12, APEC 99. 

Power Supply Cookbook, Second Edition has been updated with the latest advances in the field of efficient power conversion. Efficiencies of between 80 to 95 percent are now possible using these new techniques. The major losses within the switching power supply and the modern techniques to reduce them are discussed at length. These include synchronous rectification, lossless snubbers, and active clamps. The information on methods of control, noise control, and optimum printed circuit board layout has also been updated. 

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