DC Motor Control: H-Bridge +5A, 48v

I'm looking for a h-bridge that can handle in excess of 5A continuous,

48v. I would really like to find something with these capabilities that uses SPI to communicate with a microprocessor.

Any ideas, anyone? Thanks.

Mike

Reply to
Mike
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We looked into something like this a few years ago; at that time nobody made monolithic parts that are rated for more than 40V or so, and I doubt the situation has changed. Apex makes hybrids that will drive that sort of voltage with a logic input, but they're $$$ -- sensible if you're making a few and want to save on engineering, but not if you're making a lot.

Hopefully someone has made or will make a controller for this where you can add a couple of FETs and get a half-bridge. It certainly makes sense given that the automotive market is going over to 42V rails.

As far as SPI to a microprocessor goes -- good luck! Your best bet will probably be to put an itty bitty micro right next to a plain old amplifier.

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Tim Wescott
Wescott Design Services
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Tim Wescott

Evenly divided, which isn't too surprising when you consider that the I2C bus is sufficiently more complicated than the SPI to make it a pain to work with if you don't need the features.

Where it's a _real_ pain is when you need to implement a bunch of ADCs or DACs -- serial ADCs in particular always seem to be set up so they can't be daisy-chained the way DACs can.

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Tim Wescott
Wescott Design Services
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Tim Wescott

I could build one for you easily enough, but I'd have to charge you :)

Agile Systems has (had?) modules like this. I think they are all larger though. As I recall they dropped the low voltage stuff and concentrated on higher voltage units. You'd probably get the 5A and you would have lots of voltage headroom :)

Robert

Reply to
R Adsett

Hello Tim,

There has been many years of talk about a higher voltage bus for cars but except on hybrid vehicles and some exotic prototypes I haven't seen one materialize yet.

What is your opinion with respect to the market shares of SPI and I2C? There are two SM bus app notes for the MSP430 but the devices support both.

Regards, Joerg

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Reply to
Joerg

Tim,

Thanks for the lead on Apex. I found some really interesting components there. I knew the SPI was going to be a long shot.

Mike

Reply to
Mike

I'll check out Agile, thanks Rob.

Reply to
Mike

What type of motors were you driving?

Reply to
Mike

Trinamic

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TMC249 can be controlled with SPI, needs external drivers

Infineon TLE6209R, but only to 40V (45 VProtected)

Anyway, we decided to build such a H-bridge around the HIP4081 from Intersil as this allows voltages up to 80V without gluelogic. An Atmel AVR does the SPI-interface. This 60V/5A-bridge requires around 23cm² including EMV/ESD-parts on a

4layer-board /one side components only

hth

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Michael Wieser
Reply to
Michael Wieser

I don`t know brandnames- I saw mostly 24V/4A, sometimes 36V/3A.

Vcc in this application can go up to 60V for several seconds, usually

26 - 40V. The whole design allows a Vcc of up to 70V, main problem was heat because of Rdson and TO252/100V-FETs.

motors are controlled via pwm (5-10kHz) from the uC when spinning up, braking is done with pulling up both sides of the motor to Vcc

There is also an overcurrent-shutdown with feedback to the uC for detection of mechanical blocked motors.

hth

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Michael Wieser
Reply to
Michael Wieser

I'm looking to do something within the same envelope. Did you try their evaluation board?

Reply to
Mike

Any reason why you chose high-side braking over low-side?

Presumably the motors have high enough DC resistance that this is a sufficient loss mode for braking, so back EMF doesn't cause over-current in the FETs. Did you consider using regeneration instead? Just curious...

Clifford Heath.

Reply to
Clifford Heath

Brake-current goes up to 15A (measured with 20cm wire) for 300mS, Current limit (on lowside, 2 SMD-resistors with 40% margin @5A @Tamb=70°C) is set to ~5A So the current limiter would interrupt braking, which doesn`t happen when braking with highside-fets.

It`s an old mechanical design with some new electronis inside. To keep the old sensoring my customer decided to brake the motor some 100ms before the slider reaches the mechanical stoppers. So this "hard" brake helps to reduce mechanical stress at the stoppers. The FETs (IRFR3410) can handle these currents without problems and the sliders don`t crash as hard as with the previous design...

Yes, but much to dangerous for this design as there is no load or capacitor which can handle the back-EMF so voltage would rise to an unknown level...

hth

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Michael Wieser
Reply to
Michael Wieser

No. I jumped into a prototype without problems. Its a relative simple and handsome chip as long as you read the realated ANs carefully.

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Michael Wieser
Reply to
Michael Wieser

Whose evaluation board? I've lost track here.

Robert

Reply to
R Adsett

Intersil HIP4081, I've contacted their resellers, there is a 17wk lead time on obtaining the eval board for it.

Reply to
Mike

That's an interesting company with interesting motor-control products. Have you tried them?

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 Thanks,
    - Win
Reply to
Winfield Hill

Can you post the link? So far I all of the different Farnell's I checked don't stock it.

Thanks

Reply to
Mike

I see the chip is available, how about the eval board to go with it? I can't seem to find it anywhere.

Reply to
Mike

Here in Europa: Farnell

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Michael Wieser
Reply to
Michael Wieser

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