H-Bridge schematic?

[fitek]

Been busy with family stuff, but starting to get back into my pre-kid hobbies.

I'm looking for a schematic for an H-Bridge power circuit for motor control. Figured you guys might be able to point the way. Eagle files would make it even sweeter, but I can make those on my own

If I google, I find a bunch of stuff tied to discrete driver parts. I'm looking for something using basic parts to generate the higher than supply voltage needed. So sticking to high power FET, transistors, resistors and caps. No TI parts or anything like that.

Fechter had an old Crystalyte schematic but it had a few errors and used an IR21xx chip. Don't need any logic.

Cheers

 

[dnmun]

look up H bridge in wikipedia.

 

[fitek]

This has all stirred up a bunch of memories from long ago.

Need 3 H bridges to drive a 3 phase brushless DC motor.

An H-bridge has a high side and a low side. This connects power to the battery (high side) and then to ground (low side). Without getting into technical details, for high power stuff you can't use a P-channel and N-channel (which would be easy) because P-channel MOSFETs kind of suck, so you have to use an N-channel MOSFET for the the high side gate (the on/off switch), which then requires a higher than supply voltage to operate efficiently. So you need a charge pump circuit for the high side. There's another circuit whose name I forget that uses back to back diodes which helps with connecting to ground quickly as well. Plus it's handy to have some protection against shoot through (turning on high side and low side at the same time, sending a rush of current from battery + to -, which normally would blow up your controller).

There are all in one solutions like L298N but none of them are high voltage/current enough for EV drive.

Then there are chips which allow discrete MOSFETs off board and just handle the logic and charge pump and stuff. Example is IR2101 which is now discontinued. I had trouble finding parts > 60V. Also lots of these parts are surface mount which is no fun for soldering in the garage.

You can also find motor control ICs which handle everything and just need discrete MOSFETs. But voltage is a problem and they all seem to be surface mount as well. And that takes the fun out of the project anyway.

I'm just going to troll through gate driver IC datasheets until I find one that has an internal schematic.

 

[dnmun]

you could not use the schematic in the wikipedia article?

 

[fitek]

Well, a search of mouser makes it pretty easy.

Criteria:
type: high AND low side. ( select all options like that in mouser filters)
inverting/non-inverting (doesnt really matter. should be consistent if 2 channel to avoid driving self crazy)
at least 1a drive current
runs off 12v supply (so supply max at least 15)
output voltage at least 150v
fast switching would be nice (rise/fall times seem to be in tens of nS or hundreds, so skip the stuff in hundreds)
mouser has at least a thousand in stock
dip package

L6384E/85E STM - thousands in stock $1.82
MCP1406 - $1.06, 800 in stock, 6A baby!
IR2011 - thousands in stock, $3.45