New TO247 H Bridge
EDY19, Fri Jul 06 2007, 12:35AMI just designed this after a little playing around, and I'm wondering if anyone sees any major flaws in it inductance wise. The output is on the right hand side top and bottom, ground is on the right in the middle, and the + input is on the left hand side. The top mosfets are right side up, with the terminals in the order GDS GDS, while the bottom ones are upside down, and if labeling the terminals from left to right they would read SDG SDG. If the picture was rotated 90 degrees clockwise, the mosfets would be in the same orientation as in the traditional schematic of an H bridge. There will be a film capacitor across the positive rail to ground. Thanks!
Re: New TO247 H Bridge
..., Fri Jul 06 2007, 01:14AM
You should stick at least 1 nice big fat decoupling cap (nice low esr/eskl film) across the +/- rails, and good luck soldering the fets like that (remember, the most important thing about a bridge is that it doesn't blow fets, but the 2nd most important thing is that you can easily replace them when they do blow), but it should work just fine.
Also, it will make you life a heck of a lot easier if you include pads for at the zeners/gate resistors and the wires from the gdt...
..., Fri Jul 06 2007, 01:14AM
You should stick at least 1 nice big fat decoupling cap (nice low esr/eskl film) across the +/- rails, and good luck soldering the fets like that (remember, the most important thing about a bridge is that it doesn't blow fets, but the 2nd most important thing is that you can easily replace them when they do blow), but it should work just fine.
Also, it will make you life a heck of a lot easier if you include pads for at the zeners/gate resistors and the wires from the gdt...
Re: New TO247 H Bridge
EDY19, Fri Jul 06 2007, 01:25AM
As for the zeners- I usually solder the two back to back, bend the leads, and I'll still have enough room on the source and gate pads to do that. And as for soldering like this- thats how my last design was, so I'm not too worried- it just pays to take precautions and make sure you don't blow them in the first place!
EDY19, Fri Jul 06 2007, 01:25AM
As for the zeners- I usually solder the two back to back, bend the leads, and I'll still have enough room on the source and gate pads to do that. And as for soldering like this- thats how my last design was, so I'm not too worried- it just pays to take precautions and make sure you don't blow them in the first place!
Re: New TO247 H Bridge
Steve Ward, Fri Jul 06 2007, 01:52AM
Looks pretty good to me. Im pretty sure ive made a bridge with that exact same layout with the traces sneaking under the IGBT pins. I had to eventually insulate the IGBT pins from the board as crud had built up in there causing a short. Easy enough to fix.
Steve Ward, Fri Jul 06 2007, 01:52AM
Looks pretty good to me. Im pretty sure ive made a bridge with that exact same layout with the traces sneaking under the IGBT pins. I had to eventually insulate the IGBT pins from the board as crud had built up in there causing a short. Easy enough to fix.
Re: New TO247 H Bridge
thedatastream, Fri Jul 06 2007, 06:52AM
I've used a laminar structure for getting the supply up and down the board with +ve on the top and -ve on the bottom to reduce the inductance. I've then bent the leads of my IGBTs appropriately to contact either the top or the bottom of the board. Still added a film cap for decoupling though.
thedatastream, Fri Jul 06 2007, 06:52AM
I've used a laminar structure for getting the supply up and down the board with +ve on the top and -ve on the bottom to reduce the inductance. I've then bent the leads of my IGBTs appropriately to contact either the top or the bottom of the board. Still added a film cap for decoupling though.
Re: New TO247 H Bridge
EDY19, Fri Jul 06 2007, 11:09PM
Just bought some 44N50s so we'll see whats to come of them! Project thread as soon as i get a little time to work on it- Im thinking PLL so i can audio mod later, but I may just do a 74HC with feedback. Votes?
EDY19, Fri Jul 06 2007, 11:09PM
Just bought some 44N50s so we'll see whats to come of them! Project thread as soon as i get a little time to work on it- Im thinking PLL so i can audio mod later, but I may just do a 74HC with feedback. Votes?
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