H-bridge circuit.

Jun 04, 2008 5 Replies

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seegoon99 18 years ago

Hi to all. I am looking at re-designing a h-bridge circuit that we use in one of out products , to try and reduce cost. It uses 4 n-channel mosfets and 2 high/low side drivers. (IR2104 's). The cost of these is quite high.Betwen $0.7 and $0.8.These chips are rated for use up to 600V but for this product 36V would be fine. It's a 12V system.Rated current up to 15A A quick look at doing a discrete solution showed(at firsh glance)it to be impractical. The number of components used and the board space requited, showed it probably would not be a much cheaper solution(if at all). A simple discrete solution would also not have built in dead time control.

Are there any cheaper High/low side drivers out there that would be good for the job. I have looked at ON semi and IRF , but all similar chips are also just as expencive or more so. Are we maybe at the cheapest solution already and I'm wasting my time.

Cheers Rob

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legg 18 years ago

What's wrong with your controller's dead-time control?

Using an isolated driver in a 12V system is silly, but are you sure this is where there's the most fat to cut?

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Tim Wescott 18 years ago

I have investigated this, too. I don't end up considering high/low side drivers for their dead time control, I end up with them to push the electrons in and out of the MOSFET gates. Find me a cheaper driver that doesn't have dead time control but does have the speed and I'll buy it; until then they all seem to come with it.

I don't know what the washer manufacturers do for their three-phase VFD controls: use discretes and cheap Asian labor to stuff them into boards, probably.

Tim Wescott Wescott Design Services http://www.wescottdesign.com Do you need to implement control loops in software? "Applied Control Theory for Embedded Systems" gives you just what it says. See details at http://www.wescottdesign.com/actfes/actfes.html

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Tim Williams 18 years ago

I have a scrap (Maytag?) board that uses 6 x MOSFETs and some IR2xxx drivers, one for each pair (half bridge) I think.

Tim

-- Deep Fryer: A very philosophical monk. Website @

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Jamie 18 years ago

You call .70/ .80 expensive? My god!@, Did I miss read that or what?

"I\'d rather have a bottle in front of me than a frontal lobotomy" "Daily Thought: SOME PEOPLE ARE LIKE SLINKIES. NOT REALLY GOOD FOR ANYTHING BUT THEY BRING A SMILE TO YOUR FACE WHEN PUSHED DOWN THE STAIRS. http://webpages.charter.net/jamie_5"

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# 18 years ago

Maybe Fairchild FAN73832? Or FAN5106B but that one goes only up to 15V or P-fet

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