Part Number:DRV10866EVM
Hi,
I am using the DRV10866 in a closed loop application. The current limit resistor is the default 3.8k. With a light inertia the motor starts up quickly and robustly. With a higher inertia motor it mostly does not start unless I give a spin by hand. Left untouched it goes through several attempts at starting up but I don't see the Fg pin toggle. It stays high.
This motor has low resistance (1 ohm phase-phase) so I added 6 ohms phase-to-phase to limit start current. Is this needed or should I just rely on the DRV10866 current control? Would this additional resistance be detrimental to the start-up bemf detection? The use case is the motor will be started and lock within about a couple seconds but then stay on for literally hours.
How small can I make the current sense resistor? There appears to be a region where if the acceleration is too slow the bemf can't be detected. Any advice on how to proceed. FYI, the nominal run speed is 3600 RPM with Vcc=5.0V.
Thanks,
Brian