This week’s EYE ON NPI (video) will drive it’s way into your heart and into your motorized design BOMs: it’s the Texas Instruments DRV8411 Dual H-Bridge Motor Driver.
This is a nifty multi-purpose dual H-bridge driver for use with either two brushless DC motors or bi-polar stepper motor.
This driver features a wide operating voltage, from 11V down to 1.65V, and up to 4A current output so it can be used in just about any motor control design.
It’s intended as an upgrade replacement to the popular DRV8833, with pin-compatible options or with reduced BOM options if you’re good with a little redesigning.
Now you might be thinking: Hey, that DRV8833 part number sounds so familiar – where have a I seen that before? Well, if you were thinking that you saw our Chip Shortage video clip from about 1 year ago, we were desperately begging for some DRV8833’s in PWP package so that we could get Crickit boards back in stock.
We did get some eventually, so that we have both our Crickit and DRV8833 breakout boards back in stock, but now we’re looking at maybe updating the design with this fancy upgrade.
The original DRV8833 is a great chip, and can drive two DC motors or one stepper at 2.7-10.8V and peak current of 2A. To compare, the DRV8411 has a wider range of 1.65-11V which means its better at low voltage motors, say ones running off of 2 alkaline batteries.
It’s also available in 4A peak output transistor as the DRV8411A – double the current!
Note that if you are pushing that much current, at long intervals, through your driver you will have to think about heat-sinking. There’s a section in the datasheet about how to use copper fill as a heat sink: 2 oz copper will do better than 1 oz and you’ll want a large square area. Otherwise, you may have to look at adding an external heatsinking or forced cooling with a fan.
Or, you may want to avoid getting into such a hot state by adding current limiting. These drivers can use a resistor that is in series with the motor power to limit how much current will sink: once the voltage across the resistor hits 200mV, the feedback system will reduce current draw. Our original breakout used these power/current-sense resistors to limit current to 1.2A by default.
One nifty feature we saw in the DRV8411A version of this family is they’ve gotten rid of the ‘in path’ current sense resistors. While they worked great they needed to be high wattage in order to handle the full current from the motor path. The A changes this to a current mirror so that low wattage resistors, say 0402 or 0603 size, can be used instead saving a ton of space. You can also connect the monitor pads to your favorite microcontroller ADC to monitor current draw.
And, oh yes, the DRV8411 and DRV8411A are both in stock right now for instant shipping from Digi-Key! When you order from Digi-Key they will pack and ship your order from Thief River Falls within the day and you will get it as quickly as tomorrow morning so you can get your motors twisting and turning with this fabulous NPI.