"Jeff Liebermann" wrote in message
...

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.

A step-down regulator/converter could be made from a Microchip PIC18LF14K22
(http://ww1.microchip.com/downloads/e...Doc/41365c.pdf) which has a
quiescent current of 34nA and an operating current of about 10 uA at 1.8
VDC.

And it may be even more efficient to use a low power linear regulator such
as the TPS71501 (http://www.ti.com/product/tps71501) which has 3.3 uA
quiescent current. If the input voltage is, say, 2 VDC and the output is 1.6
VDC at 12 uA, the overall efficiency is (1.6*12)/(2*15.3) or almost 63%.
Even at 3 VDC input it is 42%.

Paul