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Brushless ESC - help for MOSFET driver circuit.

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You need the boost feature of the 1/2 bridge drivers to drive the high side FETS.
 
We are in the dark without your schematic. Can you post it?

I have never seen a design in which N-channel mosfets drive a load (i.e., are high side) without some way to get Vgs > V load (Vd). If you have seen such a circuit, please post an example.

John
 
Why such large gate resistors on the mosfets? Something in the single or low double-digit range (like 4.7 to 22 Ω) may help, if ringing doesn't become a problem. Also, at higher currents, the current gain from the 2N3904's may not be enough to drive the mosfets quickly. 2N2222's will give you more current. In either case, you may want to reduce the base resistor. How much can the MCU output per pin? (I am more familiar with Microchip PIC's.)

John
 
Your schematic was a bitmap which used 1.5MB. I opened the zipped file, cropped the huge schematic, increased its contrast and saved it as a PNG file that is only 10.2KB.

No wonder the Mosfets get hot. The 2N3904 transistors are emitter-followers instead of as switches so the gates on the turned on Mosfets are only +4.3V when they should be +15V or +18V.
Nothing turns off the Mosfets when they should be turned off so both Mosfets are turned on at the same time.
 

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If you use the bootstrap circuit you should take the advice already given to make the base resistors smaller (say 470 for R2 and 750 for R3) 2N2222 would be a better choice. 30 ohms for the gate resistor is probably ok because the driver can't drive more anyway. The IRF530 is probably not the best choice either. In general, lower voltage FETs will have lower RDS on and be more efficient. Don't forget your clamp diodes. I can't see all your schematics, and I doubt most others can either, so you should learn how to put them on right if you want to get help. You can always do a print screen of your schematic, paste it into paint and then save that as a .png file. Then just upload it as an attachment.
 
If you are in the US you can get FDP8447 from Mouser for a little over $1. I would buy a good half bridge driver at the same time, but your transistor driver will work - just not as good. Get some diodes to clamp the inductive kick from the motor windings.
 
Tell us a little more about your motor. Maybe someone here has an brushless schematic that is proven.
 
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