Measuring efficiency of U1V10F3 / U1V10F5 boost regulator boards

I am using the U1V10F3 board (based on the TI TPS61201 IC) to provide a stable 3.3V form 2x AAA alkaline batteries to am ESP8266 based project that draws roughtly 75mA most of the time but occasionally requires bursts of up to 240mA.

As far as I can tell, this is precisely the kind of application the TPS61201 was designed for and sure enough it supplies a beautifully stable 3.3V as the battery voltage declines. However, when trying to measure the boost regulator efficiency I am getting some hopelessly poor efficiency measurements.

With a (measured) stable output current of 71mA I am seeing an input current of 660mA at 2.4V, which cannot be right. The board should be in the region of 80% efficient under these conditions, giving around 90mA at the input.

I have simplified the vreg circuit to its bare essentials, connecting VOUT to GND on the U1V10F3 board via a few resistors in parallel to create a load such that the output current measures 105mA, yet I’m still measuring 670mA on the input side. Interestingly, when I bring the output load down to 25mA, the input current hardly changes.

I can only assume I’m measuring the input current wrongly somehow - although I’m doing it the same way that I’m measuring the output current. I think the TPS61201s power save mode may be implicated. Any tips, anyone?


That does seem like a high input current for those conditions. Could you tell us more about how you are testing? What are you using to measure the input and output current? Are you monitoring the input and output voltages? Have you tried measuring the quiescent current (the input current with no load)? Could you post pictures of your test setup that show all the equipment and connections?