Thread
:
Repaired Harbor Freight digital caliper
View Single Post
#
104
Posted to rec.crafts.metalworking,sci.electronics.design,sci.electronics.repair
Jeff Liebermann
external usenet poster
Posts: 4,045
Repaired Harbor Freight digital caliper
On Fri, 25 Nov 2011 21:28:54 -0800 (PST),
wrote:
On Nov 25, 5:31*pm, "
wrote:
(...)
http://www.ti.com/lit/ds/symlink/tps62050.pdf
From the graph on the front page, it looks like n = ~35% @ 15uA
output. That's actually very good. Thanks.
That's because of the 12uA typical quiescent current, where the chip
draws about the same current as the caliper load. For equal currents,
that's 50% maximum efficiency. The TPS62054 shows 50% efficiency at
2.7V in and 1.8V out (See Pg 8 Fig 4).
The chips do have a shutdown pin that cuts the quiescent current to
"less than 2uA". Still high, but much better.
--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Reply With Quote
Jeff Liebermann
View Public Profile
Find all posts by Jeff Liebermann