I first tested with 2 inductors at low voltage (~200 Vo): 86 uH and 89 uH.
Then I replaced them with another 2 inductors, and actual voltage (320 Vo): 64.1 uH and 64.4 uH. It got worse.
See 3 different waveforms below, at 3 different random combinations of load and input voltage (always below 30% load).
The first one shows malfunctioning.
Oh and sometimes they sit there in-phase.
I did a test where it was in phase vs. out of phase (maybe 160*). 2 different conditions.
I measured the GDA and GDB widths, by measuring the time from where the waveform just begins to rise, to where it just begins to fall:
in-phase condition:
GDA 547 ns
GDB 551 ns
(GDB is 0.7% wider)
out of phase condition:
GDA 1.441 us
GDB 1. 439 us
(GDA is 0.1% wider)
That's a change of 0.8%.
Looking at Fig 11 of the datasheet, it looks like 30* of change in phase should produce a 2% change in on-time. (Rtset = 66 kΩ)
Above I'm only getting 0.8% of change with about 160* of change in phase.
I am using the LM5112 gate drivers to drive my FETs, and I double checked the differential error in on times and it is only 7 ns. (i.e. if driven with identical on times, their outputs' on-times are different by 7 ns)
What gives?
Fig 11:
