Snubber Circuits

Snubbers absorb or redirect energy from parasitic inductance ringing at turn-off or commutation. Even well-designed resonant docks use snubbers on auxiliary switches, clamp diodes, or during development when loop inductance exceeds target.

Over-snubbing slows transitions and kills efficiency; under-snubbing risks avalanche and EMI.

01Types

• RC snubber across switch or transformer leakage — simple, dissipative.
• RCD clamp capturing energy to a cap then bleeding through resistor.
• Active clamp or regenerative snubbers — higher complexity, lower loss.

02Tuning method

Measure ringing frequency and amplitude on prototype with minimal snubber, then add capacitance until damping is acceptable without excessive loss at full load. Temperature and bus voltage corners both matter.

03Production discipline

• Snubber component tolerance affects repeatability — specify and test.
• Remove development-only snubbers before cost-down unless margin requires them.
• Document snubber heat on thermal camera during soak test.