Hello,
i am currently trying to adjust the LT8361 SEPIC and inverter boost topologies to my needs.
SEPIC (datasheet page 1):
Inverter Boost (datasheet page 28):
I want to get the full input voltage range for the SEPIC (up to 60V) going if possible, running stable at low loads (<30mA @24V max.)
Also I'd like to get the inverter boost topology up to 24V input voltage, so i can use the output of the SEPIC as input - if possible.
I tried going just a bit above the 48V on the SEPIC, but holding 50V input for a few seconds @24V <10mA output fried the LT8361.
I then increased the capacity on the SS pin to 300nF, but the second one was fried as well.
If i understand the datasheet correctly, SS only adjusts the ramp-up speed of the peak current, not the maximum peak current itself
The datasheet has some applicaltion examples for the Vc external compensation following page 20 onwards:
4-48V in @400kHz 24Vout : 16.2k 6.8nF (this is the one i fried with applying 50V)
3-60V in @450kHz 12Vout : 28k 4.7nF
10-48V in @450kHz 48Vout: 24k 3.3nF
However i am unsure how to adjust the R and C values to be "easy" on the internal switch. My primary concerns are reliability and lifetime, the ramp up of the output voltage can be quite slow (<3s).
The datasheet points to Application note 76, which i am currently working through (https://www.analog.com/media/en/technical-documentation/application-notes/an76.pdf) but this appnote goes much more into detail on how to reduce output capacitance.
Can someone give me a few rough pointers how to adjust the values for R and C on the Vc pin? (Or tell me if i'm on the wrong track entirely for achieving the higher input voltages)
Thanks in advance!
Best regards,
Michael
