Hello,
I am currently using the DRV8303EVM with the InstaSPIN BLDC sensorless control algorithms to drive a motor, but am wanting to use Hall sensors to do sensored control.
However, when plugging a Hall sensor into the DRV8303EVM board, I am seeing a very noisy signal.
The below image is what I am seeing when using an oscilloscope probe whilst spinning the motor using the DRV8303EVM board
Is there any on-board signal filtering that I could use?
Thank you,
David
Hi David,
Looking at the DRV8303EVM schematic, the Hall effect interface looks like it has RC filtering:
If this filtering is being used, then my next suspicion is noise from the GND plane. The DRV8303EVM uses a common plane, so noise from the motor current switching could be coupling into the Hall signals. This noise is caused by switching large amounts of current quickly through the MOSFETs by switching the MOSFET gates on rapidly.
I'm not sure if there is a way to measure the ground noise on the EVM, but could you try lowering the gate drive resistors R13-R18 below to higher values (i.e. 10 to 20 ohms) to see if this helps decrease the MOSFET slew rate?
Also confirm that there is not a lot of noise generated on PVDD or VCC_5V that could be coupling into the Hall signals.
Thanks,
Aaron
