LTC3780 step up down board schematic

• LTC3780 step up down board schematic
  Posted by 1.6e-19 on 11 Jan, 2022 16:34
• Hi guys,
  
  this widely available LTC3780 board (hope photo appears somewhere below) is quite nice for all kinds of voltage and current sources.
  Being an step up/down it provides CV and CC from almost any input voltage.
  Alas, as often with these cheap chinese boards, it has at least one flaw: the input undervoltage protection has no hysteresis and apparently no lowpass. Making it overly sensitive - when you want to use that feature.
  I fiddled in some positive feedback to the comparator, so it gets a hysteresis, what works quite well.
  But still the thing is too sensitive and tends to get unstable.
  HAS ANYONE SEEN A CIRCUIT DIAGRAM of this board? Would help a lot debugging. Maybe some components are wrong, would not be first time on such boards.
  
  
  

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• #1 Reply
  Posted by Faringdon on 16 Jan, 2022 11:55
• https://www.analog.com/media/en/technical-documentation/data-sheets/LTC3780.pdf
  
  Have you tried come capacitance on the RUN pin?
  Otherwise, you could just make an inline module for it, which does UVLO with required hysteresis...then connect the LTC3780 to that...
  You would then disable the one on the LTC3780 board......change the resistor to RUN pin or whatever.