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Shutting down the NCP3063B Buck SMPS controller
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ocset:
We would like to be able to shut down the NCP3063B...or at least, put it into a mode whereby it draws less bias current. –Less than the 4mA or so that the datasheet says the NCP3063B draws.
The NCP3063B has no “official” shutdown pin.
As such , we were thinking of adding a 1uF capacitor to the Timing pin and putting a small NFET in series with it. Switching this relatively large capacitor in would mean a vastly reduced switching frequency, and hence less bias current draw of the NCP3063B...would you agree?

NCP3063B datasheet
https://www.onsemi.com/pub/Collateral/NCP3063-D.PDF
mariush:
the *3063 is such an ancient and just plain average series of regulator these days, you can do so much better with maybe just a few more cents when it costs to the cost of the chip.

Why don't you find something with an ENABLE pin and potentially running at higher frequencies, allowing you to use smaller inductors and ceramic capacitors instead of tantalum/electrlytic/polymer for example (less space wasted on pcb)
capt bullshot:
I don't think reducing the switching frequency will reduce the quiescent current.
What about disconnecting the GND pin using a small N-Fet?
ocset:
Thanks
We are using NCP3063B for 24V->6V at 20mA, and also for 24V->16V at 50mA

For this purpose, we cant find anything  else anywhere near as cheap as the NCP3063B.
The next up seems to be the LM5019, but this costs a lot more.

The NCP3063B has the great advantage of allowing us to set the peak current with the sense  resistor, this means we can use a smaller inductor. Some of the othe rmonolithic ones have a high peak current threshold, and no ability to adjust it.
Why do you say NCP3063B is low quality?. We dont mind the bias current, and the switch voltage of around 1V is perfectly OK for us.
bd139:
TI do a whole document on this http://www.ti.com/lit/an/slla339/slla339.pdf

I still like these regulatiors. They’re pretty much unconditionally stable.
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