Paul Nicholson skrev:
R-burden should match a manageable number of turns on a current transformer, which, at the peak primary current, will produce an output of +-15V or less, as this is the input voltage range of the AD790 comparator. (And at the same time, not produce more than manageable heat due to RMS current heating)If only a short lead time is needed, quite a flat delay is obtain with R-burden=1.2, L-burden=250nH and 11.2 ohms damping resistance across L-burden. The lead time changes from 195nS to 214nS from 20kHz to 300kHz. Might have to resort to some arithmetic here to find a rule for setting the RL burden. -- Paul Nicholson --
I have nice formula for RMS current in DRSSTC, derived by Steve Conner: Irms = 0.5*Ipk*sqrt(Ton*BPS)Lead time is fine for smaller IGBT´s, but not enough for the mighty CM600, which has switching delays in resistive switching, and Rgate 2.1ohm:
Turn-off delay time = 450nS Fall time = 350nS Not as bad as I seem to remember..... Cheeers, Finn Hammer _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla