Designing R2CD Snubbers Using Standard Recovery Diodes

Focus:

Compared with a standard RCD snubber, the R2CD snubber, offers better efficiency, lower EMI, and reduced cost even though it adds a resistor to the RCD configuration. This 4-page article describes operation of the R2CD snubber, its benefits (and where to use it), how to model it and how to design this snubber circuit for the intended SMPS application. It also dispels the myth that diode storage time is required to be the resonant half period; instead showing that it be greater than the resonant half period. Efficiency of the R2CD is compared against RCD and resonant snubber configurations in a kilowatt-level full-bridge dc-dc converter. Simulation and measured results are compared for an R2CD snubber in a 2-W housekeeping power supply. The second half of the article goes further into simulation and design issues such as how to measure leakage inductance, design for minimum EMI, calculate snubber loss, and select the right diode.

What you’ll learn:

• How to simulate and design an R2CD snubber
• How to understand the benefits of the R2CD snubber versus the RCD configuration

Notes:

The article references the company’s website, which provides files for the schematics referenced in the article. But you must own a copy of their ICAP software package (not the demo) to simulate them.

View the Source

Author & Publication:

Larry Meares, Intusoft, Power Electronics Technology, Mar 01 2013

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