In this video, Sam Ben-Yaakov delves into the analysis and design of diodes RC snubber in circuits involving high-frequency switching, such as boost converters. The video provides a detailed explanation of how RC snubbers, consisting of a resistor and capacitor in parallel with a diode, mitigate the harmful effects of stray inductance, which can cause oscillations, voltage spikes, and electromagnetic interference (EMI). Using a boost converter example, the presentation discusses scenarios such as the “turn-off” phase, where current rushing through the diode loop causes voltage spikes, and the “turn-on” phase, where abrupt stopping of reverse recovery current results in dangerous overvoltages. Calculations and simulations in LTSpice are demonstrated to determine the optimal values for the snubber capacitor and resistor to balance energy absorption, minimize voltage overshoot, and prevent circuit instability.
In the context of a 24V input, 12V output, 30W industrial power rail application, the impact of snubber component values on circuit performance is thoroughly explored. Prof. Ben-Yaakov explains the trade-offs between larger capacitors, which reduce voltage overshoot but extend discharge time, and resistors, which must be carefully sized to avoid excessive dissipation or high oscillations. The video also touches on the classification, parameters, and behavior of supercapacitors, alongside tools to support design processes, such as Support Note SN009, Application Note ANP077, and a Supercapacitor Bank Calculation Tool. These resources and the LTC3351 software from Analog Devices are highlighted as valuable aids in designing power stages and improving circuit reliability. Ultimately, the RC snubber is shown to be an essential tool for protecting diodes and ensuring stable operation in high-frequency switching circuits.
Video content
- Introduction to RC Snubbers
- Boost Converter Example
- Snubber Design Principles
- Calculation and Simulation
- Challenges and Considerations
- Supercapacitor Integration
- Design Support Tools
- Practical Takeaways
