Hello.
I have DRV8840 on TI CPG005_DRV88xx Evaluation Module.
Load: DC motor R = 6.9 Ohm, L = 0.309 mH and inductor R = 2.6 Ohm, L= 1.36 mH. Total R = 9.5 Ohm, L= 1.669 mH.
VM = 24V.
Current sense resistor RS = 0.25 Ohm.
I (0-4) = HI.
DECAY = HI (fast decay).
VREF = (0 - 3.3) V.
Peak current control quality is an evaluation goal.
At low Ipeak = (10 - 200) mA PWM frequency is 50 KHz, as stated in datasheet. When I increase VREF (and Ipeak) PWM frequency
lowers twice, to 25 KHz. Increasing current further lowers PWM frequency twice again, to 12.5 KHz.
Is that behavior normal?
Thank you,
Yuriy