switching regulator question

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sweethomela8

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I'm bringing a board up for the first time, and cannot get an exact amount of current needed on my voltage rail (+3.3V), so I decided to protect myself by getting a switching regulator that can provide up to 10 Amps @ 3.3V.

The data sheet says that the efficiency is about 85 percent if I'm using 2 Amps or more and if I'm using less than that, the efficiency drops to 50% at the lowest.

Will I run into any problems if I go below the 2 Amp consumption point where the efficiency drops to 50%?

In other words, at what point will my regulator not be able to regulate +3.3V and provide adequate load current anymore?

Thanks.
 

A property of some switching regulators is that they can't regulate properly with very low or no load. A common old PC AT supply is an example of this. You should refer to your regulator's datasheet or manual and make sure there's no notion of minimum load.

If there isn't, you should not encounter any problems.

At low power, the ratio of the regulator's own consumption and the delivered output power will be less ideal, thus worse effectivity. But that says nothing about the output being any unstable or anything. Unless said otherwise in the datasheet, your regulator should be able to give the rated 3.3V at any current demand between 0 to 10 Amp.

JS.
 

If a switching regulator requires a minimum load current, it should be clearly specified in the datasheet. I know minimum load current specification
only with multiple output supplies, when the outputs aren't regulated fully independently. This is the case with said PC supplies, also with some
isolating DC/DC converters.
 

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