Calculate current consumption for TPS63030

Hi folks!

I want to ask a question regarding the current consumption of the TPS63030. I have made some calculations, but wanted to be sure that there is nothing wrong with this.

If the load current at the output of the regulator is 27.4uA, then I guess that the total current consumption of the regulator is
[1] the quiescent current (35uA as stated in the datasheet) and
[2] the current required due to the efficiency of the regulator, which at this load current level is around 60% or less (I am talking about the diagram in Figure 3 / page 7 of the datasheet). thus we need an extra 27.4uA * 60% = 16.44uA

Total current consumption is 16.44uA + 35uA = 51.44uA

Isn't that correct? Do you see any error in this? Is there any other current that I have not taken into consideration?

--
Nick

hi Nick,
The slope of n% on fig #3 is 60% at 100uA 'output current', which I would not think the quiescent current should be included, also the slope is quite steep from 200uA to 100uA.

Summary, I would have thought the n% would be much less than 60% at 27.4uA.

I guess the only way to be sure would be to build and measure..

Eric,

you have probably right. The efficiency at 28uA is probably much lower than 60%. And moreover, I agree, the diagram is using the output current of ther regulator and thus the quiescent current should be included when finding the efficiency. The quiescent current should be added to the final result of the Iout * η% calculation (where η is the efficiency).

Thanks!