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Würth Elektronik Watts Up Podcast


Feb 24, 2022

Even though a switching regulator may produce a constant output voltage at the end of the development phase, often, designers encounter unpleasant effects, such as unwanted oscillations, at the input. So why does the input of the switching regulator tend to oscillate under certain circumstances? In this podcast, we examine "negative" resistance and come to the understanding that the sign is based on a behavior which can be attributed to transients. Download the complete Application Note, ANP008, at www.we-online.com/appnotes or click here. 

Figure 1:

Voltage Divider with Ideal Resistors

Figure 2:

Negative slope whose differential quotient can theoretically be used as base

Figure 3:

Rising input voltage then the negative resistance rises

Figure 4:

Simplified arrangement of a switching regulator with input filters