Placing the EMI filter on the input doesn’t help here.
Noone has been talking about a faulty ground clip. The problem is about inappropriate measurement methods.By suspecting the root cause of the ringing may comes from the faulty o-scope ground clip
mister_rf has been talking about a better PCB layout. A realistic conclusion could be: You simply shouldn't expect better results from a stripboard. But I guess, even a stripboard can perform better.The ground plane is already the shortest I can do in terms on a stripboard.
From the pictures you have attached I was assuming you have placed the filter on the input power lines. That's correct?
Adding a low-pass EMI filter on the input lines is designed to reduce high frequency currents getting into the power line and to prevent interference on the other devices connected to the electrical wiring.
Based on this idea, placing a EMI filter on the input doesn’t reduce the output noise.
O.K., I see that no control ground separation problem for Vgs exists due to the IR2117.
But the question of input supply connection holds. You are connecting Vin+ through a cable or clip to the input capacitor. But where's Vin- connected?
I noticed the non-monotone Vgs waveform. But without knowing the exact measurement conditions, it's likely to jump into conclusions. Vgs is floating, you'll need a good differential probe to measure it correctly in this circuit.
You can interprete the zoomed waveform also this way: The ringing is already initiated by the rising edge of Vgs. It may be the case, that a small oscilllation of Vgs is further increasing it, but it would be there with a monotone Vgs rise as well. It's completely plausible, that oscillations are observed at the switching edges, if a circuit is able to oscillate.
On the other hand, slower Vgs edges will very likely reduce ringing. Switching speed can be most simpy reduced by increasing Rgate. Unfortunately, switching loss will be increased, too. It may be a necessary concession to stripboard layout.
Unfortunately, switching loss will be increased, too. It may be a necessary concession to stripboard layout.
Placing a lossy network across a bypass capacitor is like a confession that you don't manage to provide appropriate low impedance bypassing for your circuit. But 100 pf + 100 ohm is about useless in this relation. You would primarly think of microfarad ceramic caps to be supplemented to the electrolytic capacitor. If series R at all, then in a few ohms range. Basically, the R of a snubber can be tuned to the characteristic impedance of the resonant circuit.I've been advise to add a RC snubber across +Vin and PWR GND! However I've read that adding a smaller cap in parallel with a already dominated by a huge capacitor path is of little use mainly because capacitance add up when in parallel.
As we already know from my circuit there is a 100uF bypass cap at +Vin, would the additional RC snubber, like the method above, say 100 ohms and 100pF works ??
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