Post
Topic
Board Hardware
Re: BM1384 Pod Miner plus trade-in/recycling - an interest and feasibility poll
by
NotFuzzyWarm
on 29/04/2016, 16:22:35 UTC

If anyone's wondering, I'm using a pulled TPS53355 to generate about 2.6V across four nodes of BM1384. The '53 has an internal 5V LDO which drives internal switching circuitry and powers the switching FET gate drives. When the load increases, this 5V starts to sag. It's not a problem on any of the commercial miners I've looked at, and I've replicated some of those circuits in test but it still misbehaves on mine. I noticed some inordinate gate drive currents dragging it down, so a resistor inline with the boost capacitor solved some of that. Yesterday it started working beautifully after increasing the boost capacitor and 5V bypass cap, but now with the same parts in place it's still sagging so I'm a bit perplexed. Anyway it's running right now at about 175MHz because if I push it farther the 5V sags below 4V and the buck resets. I'm sure it's something very trivial that I've overlooked.
pm me a pic of yer circuit. Have you looked at the gate drives with a scope? I'm guessing either the switching times are off or possibly oscillations.

And of course definitely interested in one Wink