# H- bridge 150v and 0-150mA.

Discussion in 'General Electronics Chat' started by sadn3ss, Apr 11, 2010.

Apr 11, 2010
3
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Hi, i need help in this project.

I have a step up from 9 to 180v. And i need to drive a load with controlled current from 0-150 mA, the load varies from 0-1kohm.

Idea:

1-Step-up gives the Power
2-I need a current source with voltage controller. Problem how? Any ideas?
3-Drive the amps throw a H bridge, so i can +-current.
4-What to use, mosfets or bjts?

What i was trying to do was, i have the power and connect the dc/dc to the h-bridge, and putting a high voltage bjt npn connected like this base 5v throw a dac, in the emissor resistance with 25ohm, so i can have the current i need, throw the emissor and collector. Problem, the top transistors PnP, and i wanted to controll more than one bridge.

Maybe a solution with a 150v and controlled current source right after the dc/dc and then connect this to the h-bridge. Does anyone have an idea how to do this source current, providing current to the h-bridge?

2. ### KMoffett AAC Fanatic!

Dec 19, 2007
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What's the 9v source? Whenever I see someone trying to power something with "9V" I assume that they're intending to use a small rectangular 9V battery.

Ken

Apr 11, 2010
3
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Yes forward in the project it is intended to use a battery. Now only a voltage source.

4. ### KMoffett AAC Fanatic!

Dec 19, 2007
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180V*0.15A = 23.4W = 9V*2.6A...this is assuming 100% conversion efficiency...impossible with a small 9v battery.

ken

Apr 11, 2010
3
0
I havent thought in that problem, only in the bridge. Yes it has to be bigger.

Jorge

6. ### retched AAC Fanatic!

Dec 5, 2009
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The closer you can get to the 180v the better you will be. Even if it is a 12v source. But I would recommend trying for at least 24v.