Quick question: parallel LM317

[jackinnj]

Originally posted by jcx
Sorry guys but you're all wrong

you may get lucky but you shouldn't literally parallel pins of a pair of feedback amplifiers -which is what the Vregs are

if the internal Vrefs, loop gains don't match very exactly then the low impedance outputs will not share the load equally, with the Vregs only being able to source current at least it may not blow up like opamp or chip amp outputs tied together without sharing/limiting series R, but likely one reg is supplying 90% of the current

pinkmouse' approach is fine if you have a spare ~ 1 Volt of headroom

yupp, National shows 0.22R load balancing resistors -- in using the SimpleSwitchers from National, all you have to do is stack the devices. I don't think that these buck/boost regulators get a lot of use in quality audio circuits.