3 ms·
Would work, but I'd estimate that it would require 4x the circuit area that this fella is working with. Plus adding some Z axis height for the optical encoder.
by cushychicken 3y ago
Would work, but I'd estimate that it would require 4x the circuit area that this fella is working with. Plus adding some Z axis height for the optical encoder.
For what he wants to do (real small, real light PCB based BLDC motor), I'd say his approach is right on track.
- topspin 3y ago> it would require 4x the circuit area A DAC would involve a larger PCB. A small DDS (si5341) would be pretty good though at 3x3mm. Three phased channels could drive the six inductors far beyond any feasible speed here. > Plus adding some Z axis height for the optical encoder. A SMT photodiode and IR LED could do this off the edge with some fiddling, which appears to be in ample supply here.
- cushychicken 3y agoHuh? That DDS is a silly choice. For one thing, those chips are $27 a pop and only available in QFN44 and QFN64. (May have been smaller FF at some other point, but not any more.) The final BLDC driver he selected is like $1.50. Not to mention that you can't adjust the drive phases of a DDS with I2C fast enough to be of any use for BLDC. Once you add in a sensor/feedback element, it definitely wouldn't have the latency performance you'd need for BLDC.