I just picked up an 18v25 CS brushed DC motor driver board to play with, but the controller’s markings are cleverly etched off. Was wondering if anyone knew what controller it uses (something off-the-shelf? an AVR or PIC with custom firmware?) before I go and try to figure it out based on the pinout.
We are intentionally hiding the markings on the chips, so we’re not going to tell you what the chip is. We also don’t want misinformation hanging around on our forum, so we request that others do not post guesses here about what the chip might be.
If you need to know more details about the internal workings of the board for you to incorporate it into a high-volume project, you can contact us directly, and we can make arrangements for getting you the necessary information.
Otherwise, if you have some questions about how to use the board, we can help you here.
hmm. Don’t recall seeing that done before.
Nope, just a hobbyist following the age-old tradition of trying to figure out how stuff works.
My microcontroller guess was pretty poor – because you’re using a quad-NPN H-bridge, the high-side gates apparently need over-battery voltage to open properly. I accidentally connected 24V to the 5V regulated output (woops!), and fried the controller, so I pulled off the MOSFETs, tested them, made my own Arduino-controlled H-bridge, and wondered why the motor was only getting about 2V in each direction.
Yeah, making high-power H-bridges is not necessarily that simple. By the way, MOSFETs are not called “NPN”. Also, if you want to give our product another try, you can contact us directly, and we can get you a discount coupon for a replacement.
Ah yes, N-channel.
Also, apparently the optional capacitors act as an overvoltage snubber? The docs just say it “decrease[s] electrical noise”, and I was like pfft, didn’t install it, and killed a 24V one when disconnecting a powered motor when running around 8A at 24V, I think due to wiring inductance.
Yeah, those caps are crucial if you have more than minimal current involved.