Posted on September 26, 2014 at 22:05I'm having a similar issue as someone else posted last year. We had problems with overheating of the IC, so I increased the slew rate and that helped. But now, we're seeing random over-currents and I am wondering if dropping the fast decay duration alone will be enough. We have several motors in the 3 ohm/ 3mH range, My current parameters are what was recommended for the L6472 Eval board:
POW_SR = 00
ton_min = 4us
toff_min = 21us
toff_fast = 10us
fast_step = 16us
tsw = 48us
The advice given to a previous poster was:
Hello,
This seems to be an offset effect on the current sensing circuitry.
You can try the following solutions:
- slightly increase the target current, this way the sensing circuitry should work better
- decrease the fast decay duration (the fast decay causes the system to go out of control)
- decrease the slew rate
I tried dropping fast_step to 10us, and it seems to work ok, but the error is intermittent, and I'd like to have some margin. Any suggestions?
Also, I wonder if you can explain why adjusting the SR or fast decay helps.
#l6472-current-regulation
