Originally Posted by wiatrob
Nothing but 'baby' inductors available at the store tis weekend, so no chance to try upping the value of L1/2H.
Guys, if you want to investigate heater > 4W support, consider downloading Switchers Made Simple® V4.3
. It's a good ol' DOS app.For inductors
, it appears to report best/optimal values
but be sure to review LM2595-ADJ chart on page 12... 220uH main coil seems best compromise value for std heater targets (6.3v / 12.6v loads <= 4W). But it seems the tool may report minimum values for caps
& this would make sense because most designers are looking for lowest-cost solutions. We aren't
For what you are after, ripple filter comp values require you need to dig deeper. Optimal ripple filter cap value might be 180uf -> 220uf for what you are trying to do. But remember, it seemed heater circuit noise was NOT from tube heater element side of switcher, but from switcher's impact on common A/C. You will have to get cozy w/your scope I think, but don't forget your ears are the real judge