I’m trying to use two SMC03’s to feedback speed control two diaphragm pumps (to gas-sparge the filtration membranes in my wife’s bioreactor, fun!), and I think I’m hitting the driver chip’s current limit at start-up. Unfortunately the pump manufacturer doesn’t supply much information on the motor.
At 12V the motor just won’t start for any speed command. Running the pump straight from the 12V power supply, it only draws about 0.6A once it gets going, but I don’t have a simple way to measure the start-up current spike. If that is what’s killing it, I don’t think I’m going over what the chip can handle by much. Running from a 9V alkaline battery, the motor starts up just fine, but unfortunately slower than we need it to run.
The project budget is pretty much gone at this point, so I was hoping not to have to trade these in towards two SMC04’s. I was thinking of soldering a second driver chip in paralel onto each controller, but I see that TI isn’t making the TPIC0107B any more, and I haven’t been able to find a supplier with any left in stock.
So, I guess my questions boil down to:
Have you (Pololu guys) found a pin-compatible replacement chip for the SMC03’s?
Does anyone know of a place I could pick up two TPIC0107Bs?
Alternatively, does anyone have an idea for a sneaky way to suppress the over-current protection on the TPIC0107B?