Other Parts Discussed in Thread: TMS320F28379D
Hello Motor Drive team,
One of our customers is in nearly finished bringing up their PCB with two TI ICs on it.
Their product involves driving 2 brushless motors by TI TMS320F28379D via TI DRV8323RSRGZ driver.
They are trying to utilize the current feedback feature of DRV8323RSRGZ. The current feedback is essential for control of the brushless motor.
The output of the DRV8323RSRGZ driver (specifically SOA – pin25) is connected to analog to digital converter input of TMS320F28379D (specifically ADCIND0 – ball T5) for current monitoring.
The analog input is highly contaminated by noise (see attached presentations). They managed to isolate the noise sources.
Frequencies of noise measured by Keysight DSOX3024T oscilloscope (with standard supplied with oscilloscope probe) are correlated with two main signal sources: PWM generation of TMS320F28379D and incremental encoder of the motor.
Note that PWM noise is detected regardless the fact that motor is disconnected.
Attached presentation provide an architecture of current testing setup and a printout of the oscilloscope.
It appears that both TMS320F28379D QEP (encoder) inputs and DRV8323RSRGZ PWM inputs require termination.
Which kind of termination is required? Please instruct us on the termination value.
Please consider other reasons for such noises.
Regards,
Meir.
AV02-4927EN_DS_AEDL-981x_5xxx_2016-01-18.pdfEncoder noise .pdfPWM noise.pdf
