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Hello guys,
I would like to have some additional discussion. My arguments are in the newly attached.
Do you think a series LC tank circuit worth trying to suppress noise riding on my +28V DC?
Ok, got your meaning that u believe my common point could be floating a little. Scope's ground clip could be assumed solidly grounded to earth via the o-scope 3 pin plug. My capacitor (or in fact my entire circuits) common node is not grounded to earth. It is just simply a return path for all...
Haha, u're here too. So does it implies that all bypass cap should have some
resistance as well so that energy (or to be more precised, unwanted energy),
could dissipiate via an alternate route. If yes, why does most of the time,
capacitance are only added in parallel to form the bypass bank...
I've noticed that as long as I've only include a cap (as no resistor in series with this cap). The transient got "decayed" more faster but the trade off is the increment of higher spikes during first or second overshoot. Or to put it in other words, the "area under the graph" remains the same...
Hi Mtwieg,
Linking back to one of the guides I've found (see:**broken link removed**), I've tried to find an adequate explanation why suppressing noise at output due to turn-on transient could be more effective by adding a small but high freq effective ceramic bypass @ +Vin, rather than a RC...
Alright, I've no problem understanding that putting multiple bypass cap in parallel would:
1) effectively decrease R(equivalent) because of 1/Req = 1/R1+1/R2+...+1/Rn
2) decrease inductance as well cause just like resistor, they add up in series while reduces when in parallel
3) capacitance...
Hi guys,
As advised, I've removed the 100uF Electrolytic cap and replaced it with a 10nF ceramic cap (that's because this is the biggest ceramic cap I've at the moment, my orders are coming in tomorrow).
Delighted, I've seen a tremedous attenuation of noise pk-pk signal to about a good 1V...
Yes, I am still using the probe ground with no other choice. Basically there are 2 operationg channels in my o-scope. One is the typical hook + crocodile clip kind of probe, the other channel is from a differential probe measurements.
Attached is how I connect the probes, and what type of diff...
Mtwieg, foremost thanks for your detailed explanation.
My first approach in obtaining the RC value is actually also based on this link you've provided, however I am not sure if I've done it wrongly because instead of randomly inserting a cap across the switch node and the FW diode anode until...
Hi,
I'm reporting live from my laboratory. I just made another discovery.
All along I've been using AC coupling to moniter the vout noise amplitude.
when I forgot to connect the probe to the output.
Therer is also about the same noise waveform occurring, the only difference is
the...
Blue waveform - Vs w.r.t. Power GND(PSG)
Green waveform - V(gs)
Yellow waveform - V(out) w.r.t CG (or output filter's GND)
2.jpg shows w/o RC snubber:
Noise pk-pk is about 3.5V (Bad!)
3.jpg shows RC snubber connected across V(s) and PSG with R= 8ohms, C = 820pF:
1.jpg is when I increase Rgate...
Increasing rgate will prolong the on time for the high side switch. Not only does it increase my switching loss, it alters my duty cycle (reducing it) as well.
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...
Thank you FvM for this bullseye observation. My Vin- is connected to CG of the filter, that is, outside of the filter where in the end it meets the AGND.
I hope when I connect this Vin- to PSG instead, I'll get a good suppression of noise out there. Furthermore, could I know if it is correct to...
Im glad I have the layout with me. I've severed a point (marked with red X) and added solder so that the AGND (or control GND) are routed onto another separate dedicated track. The only point where this AGND and PWR GND meets is between the EMI filter block (PSG and CG respectively). With the...
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