How to chose a mosfet driver

I want to use 4 of these mosfet aaAUIRFS8409-7P an H-bridge. For the lower side mosfet, I can use MIC4422 mosfet driver to drive them. The driver is for heavy power mosfet and it's really fast switching according to the description and features.

Now I need to find a driver to drive the high side of the bridge, but I dont really know how to look for it. What should I look for? what number in the datasheet? What does effect the switching speed of a mosfet?

Also, If there is not fast switching mosfet driver for high sided mofet, can I control only the lower mosfets with pwm signal to control the speed of the motor, while leaving the higher mosfets always on or off?

If you know some driver that can interest me, I would appreciate that you share with me.

And for the MIC4422, there is a version, the MIC4421, that is "inverting". I don't really know what that's mean, is it important?

Thanks

Use non-inverting to drive a N-channel Gate High to turn it on. Use inverting to drive a P-channel Gate Low to turn it on.

What are you planning to use for a source voltage?

CrossRoads: Use non-inverting to drive a N-channel Gate High to turn it on. Use inverting to drive a P-channel Gate Low to turn it on.

What are you planning to use for a source voltage?

This a question about high power MOSFET bridge, MOSFET drivers are required.

There are 1000's of drivers - some idea of the precise requirements is the first stage...

Yes, driving only the bottom FETs with PWM is a valid control method. The top FETs don't switch so often, so they don't need a high current driver.

Many FET drivers are built to control H-bridges. They either have a matched pair chip available or both drivers are in one package. If you can't find a matching one from the same line as your bottom driver then pick a different line.

At high power every device needs a MOSFET driver or it’s too fragile to last long. Remember
at high power the feedback capacitance can put large currents back into the gate and overwhelm
an inadequate gate drive circuit. At high power you switch larger voltages at larger currents
faster (to keep losses under control), all of which means the gate drive is more vulnerable to
back-driving on transients that takes out the gate oxide or the driving device.

MOSFET driver chips are cheap and have various protection function built-in usually (shoot-through
prevention for instance)…

And PWMing just the low-side switches means you are limited to fast decay mode.

MarkT: This a question about high power MOSFET bridge, MOSFET drivers are required.

There are 1000's of drivers - some idea of the precise requirements is the first stage...

Well, any price is fine, I don't think that a mosfet driver can be THAT expensive anyway. The MIC4422 is about 2$. Lets say around 5$ max.

But I would need something big enough to be worked by hand, I bough a chip once and it was about 1.5mm by 1.5mm. I didn't expect that. Any through hole package would be better than surface mount. And, if possible, that it is available at this website. http://canada.newark.com/

What is wrong with the MIC4421 and MIC4422? Both are available as DIPs from Canada Newark.

CrossRoads:
What is wrong with the MIC4421 and MIC4422?
Both are available as DIPs from Canada Newark.

They are for low side mofet.

Can I setup the bootstrap thing with those driver?

What is the Supply voltage? You've never said. The parts may be able to drive at the levels you working at.

CrossRoads: What is the Supply voltage? You've never said. The parts may be able to drive at the levels you working at.

Everything come out of a 12v lead battery. The drivers and mosfets will be control with an arduino with 5v.

The HIP4081 is available as through-hole and drives a complete H-bridge, probably the best option. There are many high-low drivers (half-H-bridge) such as the IRS2001, IRS2004, FAN7380 which you may be able to get cheaper, some of these are available in DIP too.

Which supplier(s) do you use?

MarkT: It is far from straight forward as I have warned - get anything wrong and bang exploding MOSFETs, burnout MOSFET drivers.

You almost certainly want to think about using fast opto-isolators into the HIP4081 and all the timing (such as PWM) is your problem still. Because of the bootstrapped high side gate supply you cannot leave the low side switches off for more than a ms or so at a time, otherwise the high side driver bootstrap capacitor will discharge.

Fortunately the HIP4081 has extra circuitry to help here, but most MOSFET drivers supporting bootstrap don't.

If you don't have an oscilloscope and a good current-limited bench power supply you are not equiped to tackle such a project really...

You said last time that this driver is too complicated.

That's why I think full bridge, or even half h bridge are very complicated to control. I think I have better change to succeed why a single driver by mosfet and assemble them whit a relay for h bridge or managing everything in the programming.

I was thinking about something, will the capacitor for the bootstrap charge fast enough to control the mosfet at the frequency of the pwm of an arduino?

And do I need an opto-isolator with the driver for high side or this is not a problem with high side mosfet driver? I guess it depends of the driver...

MIC4421 and MIC4422 will swing 0-18V output from 0-5V gate signal. See Figure 1 & 2. http://www.micrel.com/_PDF/mic4421.pdf They actively drive the output high or low as needed for very fast transition times of just 25nS.

CrossRoads: MIC4421 and MIC4422 will swing 0-18V output from 0-5V gate signal. See Figure 1 & 2. http://www.micrel.com/_PDF/mic4421.pdf They actively drive the output high or low as needed for very fast transition times of just 25nS.

Yeah but I cannot control a high side mosfet with it right? Or can I?

Beurnii: I was thinking about something, will the capacitor for the bootstrap charge fast enough to control the mosfet at the frequency of the pwm of an arduino?

If you have plenty of decoupling (10 to 20x the bootstrap cap), all the caps are MLCC, the diode is a fast diode or a schottky diode and a nice tight low-inductance path between them, yes it will be fine. You need to make sure the cap will hold up its charge for the duration of the PWM cycle, but normally there's little leakage to worry about as everything is a MOSFET (the driver, the load)

And do I need an opto-isolator with the driver for high side or this is not a problem with high side mosfet driver? I guess it depends of the driver...

The whole point of a high-side or high-low bootstrapped driver is to avoid having to have a separate supply and optoisolation, thus reducing parts and cost. Many high-low drivers are rated at 200V or 600V and they use clever techniques to achieve this on the die.

You can of course have opto-isolation and a normal low-side driver running from a floating supply, but the floating supply isn't simple or cheap normally. For an H-bridge you'd need two floating supplies, which is even more expensive.

Well according to this video, the capacitor take quite a long time to lose its charge. It takes a few minutes.

Can I use the MIC4422 for high side, is this a thing possible?

Do you know a good high side mosfet driver?

If you have a gate driver that can bring the gate to +12 for off and 0V for on, what more do you need? The MIC4422 can do that. See Figure 1 of the datasheet. http://www.micrel.com/_PDF/mic4421.pdf

CrossRoads: If you have a gate driver that can bring the gate to +12 for off and 0V for on, what more do you need? The MIC4422 can do that. See Figure 1 of the datasheet. http://www.micrel.com/_PDF/mic4421.pdf

But that would only work with p-channel mosfet, but those mosfet as a high ON resistance, so it will warm up. I want to use the AUIRFS8409-7P. Or are you talking of the MIC4421 (the inverting driver)?

And because I don't know the voltage at the source because of the load under it, the voltage at the gate most be higher than the supply voltage. There come the bootstrap capacitor.

Am I right with those two statement there?

How much current is going thru the load, and what is the load resistance?
That will tell you what the source voltage will be on the high side MOSFETs.
As long as the voltage across the motor is <2V, you’re all set.