[021] Ringing Waveforms in the Flyback Converter

The "simple" flyback converter exhibits very complex ringing waveforms due to circuit parasitics. 


PWM power supplies are plagued with ringing waveforms that can degrade performance, impact EMI measurements, and even cause failure. This article explores some of these ringing waveforms, and gives a laboratory technique to measure them easily and safely.

Simple Flyback Converter

The flyback converter is widely used in industry, but many designs do not provide the needed the safety margins needed for modern products. A major cause of this is the ringing waveforms that exist in the converters.  

article21 01

Figure 1: Simple flyback converter with main power stage components

Figure 1 shows a basic flyback converter. Ideally, this converter has square-wave waveforms across the power semiconductors. In reality, there are numerous parasitic elements that cause ringing in the circuit when the semiconductors are turned off.

article21 02

Figure 2: Flyback converter including major parasitic components, shown in red.

Figure 2 shows the dominant converter parasitics. These include:

Continue reading this article?



contact us

Our worldwide HQ
725 W Ventura Blvd
Suite H
Camarillo, CA 93010

Phone US: +1 805 504 2212
Phone UK: + 44 (0)1509 276 245
Email: info@ridleyengineering.com

Contact Us


Get Advice