18v17 SLEEP Pin sinking current

Support Motor controllers/drivers and motors
1

Hi,

I’ve been using the 18v17 motor drivers + Arduino MEGA2560 with great success in the past, but a few days ago there was a static discharge from the chassis of our robot and it seemed like that killed all of the drivers. After some debugging I discovered that the SLEEP pin on the motor driver was pulling the voltage down to roughly 3.7V if only one motor driver was connected to the Arduino pin and the driver would still work. But If I connected another motor driver to the same pin, the voltage would then drop down to ~2.9V and another would drop it to ~2.3V and in either of these configurations, the driver would not work. I was at a robotics competition when this happened so my quick fix to this was to wire 2 more GPIO pins all 3 of the SLEEP pins to send the pin enough current to maintain the 3.7V on the SLEEP pin. This worked rather well, but I know this can not be the way they should operate. Do you have any explanation for this/ could I see the relevant schematic for the SLEEP pin circuit?

Thanks
Chris

2

Hello, Chris.

We do not reveal the schematic for this board, but the sleep pin connects directly to the main driver IC, and there are no other components on the net. Given the behavior you are describing and that it began after the ESD event, it is probable that the device is damaged beyond repair.

If you contact us with your order information via email at support@pololu.com, we can probably get you a discount on some replacements.

-Nathan