I have an LM5088 Eval Board that I am using to develop an LM5088 application. Input voltage is 60-65Vdc. Output is 15V to 50V, with short 1-10mS pulse load of up to 3Amps. A programming node has been added. The Vset signal enteres through a "T" network consisting of 1K - 0.1uF to Gnd - 2.2K to the FB pin. By adjusting this Vset input, the output voltage can be adjusted over the desired range.
The Eval Board output voltage goes into a sawtooth mode when the No Load voltage is programmed to be above about 22 Volts.
How does the LM5088 logic work for "skipping HG pulses". To me it looks like the internal switching circuit must be shutting off / going to sleep for some period of time. By the time it wakes up, the output voltage has dropped significantly. The LM5088 then starts generating HG pulses, but "overshoots" the setpoint and goes back sleep to repeat the process.
What do I need to do to keep the LM5088-1 happy without having to put a 1-2Kstatic load on the 15-50V output?
Herb
Yellow is output of LM5088 Eval board.
Blue is Vset programming voltage ramped up/down by signal generator.
Sleep / Wake-up mode above about 20V output.
Improved with static 2300 ohm load
