RESONANCE EFFECTS FOR EVERYONE TO SHARE

[gotoluc]

@Groundloop,

do you think the signal generator amplifier circuit you had done for me below would work to continue testing the coils?... because I do have the parts to build it, just didn't need it since the H bridge work so well.

Please let me know.

Thanks for all your time.

Luc

[TinselKoala]

Well, I have yet to blow any of my 2104s. Of course I am only driving with 25 volts max. But I'm pushing the system pretty hard with all kinds of stuff bouncing back and forth. Mine are the SOICs too, so you'd think they would be less robust. My red Tesla bifialr primaries have very low resistance, almost a dead short, and the bridge doesn't really like that, but it has withstood it. But I do usually use a  couple ohm resistor in series to keep the current down.
One difference is that I added 0.1 mFd bypass caps between pins 1 and 4, close to the chips. This might make a difference. Also the 50 ohm resistors on the gate drives.
You've got to have the switching logic running before you put power to the mosfets.

I goofed hard, and hooked up the 24 volt battery pack polarity backwards this afternoon. Big spark! Thought I'd killed the bridge for sure. After I got things hooked up right, nothing worked. Then I remembered the 15-amp fuse I put in the circuit. It did its job. Changed the fuse, and all is OK. Nothing blew, except the fuse!

Every time I turn my system on I learn something new. I new can see a tiny blue arc in the trimmer on the end of the air variable, when I hit that exact resonance that lights the LED so brilliantly. SO I am exceeding the voltage rating of that little cap, just at that point, and limiting the voltage with the short. With a better cap...yess...
Also had no trouble lighting up a little fluorescent tube today, ...with only one wire connected....

[ramset]

TinselKoala
I've read MANY MANY of your posts

Seen all your movies at least once

However I don't recall ever hearing anything like this
          'With a better cap...yess...'

        Chet

[gotoluc]

Well, I have yet to blow any of my 2104s. Of course I am only driving with 25 volts max. But I'm pushing the system pretty hard with all kinds of stuff bouncing back and forth. Mine are the SOICs too, so you'd think they would be less robust. My red Tesla bifialr primaries have very low resistance, almost a dead short, and the bridge doesn't really like that, but it has withstood it. But I do usually use a  couple ohm resistor in series to keep the current down.
One difference is that I added 0.1 mFd bypass caps between pins 1 and 4, close to the chips. This might make a difference. Also the 50 ohm resistors on the gate drives.
You've got to have the switching logic running before you put power to the mosfets.

I goofed hard, and hooked up the 24 volt battery pack polarity backwards this afternoon. Big spark! Thought I'd killed the bridge for sure. After I got things hooked up right, nothing worked. Then I remembered the 15-amp fuse I put in the circuit. It did its job. Changed the fuse, and all is OK. Nothing blew, except the fuse!

Every time I turn my system on I learn something new. I new can see a tiny blue arc in the trimmer on the end of the air variable, when I hit that exact resonance that lights the LED so brilliantly. SO I am exceeding the voltage rating of that little cap, just at that point, and limiting the voltage with the short. With a better cap...yess...
Also had no trouble lighting up a little fluorescent tube today, ...with only one wire connected....

Hi TinselKoala,

I'm glad it's still working for you ... maybe it's the higher voltage like you say?... well at least you're still having fun

Nothing I can do now!... I even tried the circuit above and no effect

Thanks for sharing.

Luc

[Chris31]

Because pin 7 is the high side of the driver,

If you look at the block diagram of these drivers you will see HO pin 7 is using the bootstrap cap + diode for it to work.

Any spike getting to VS will blow the high side of the driver chip.

I dont even know if people are reading my post, I said this many times but it seems to be getting ignored. Reference design from the manufacturer doesnt mean its stable for every design, you will need to protect the components your self.

Anyway Ill keep quite for now and let you get on with it.