How and when is the imp006 breakout's BQ24295 5V boost output activated?

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Another potentially incredibly useful feature to me is the imp006’s built-in 5V boost output on the BQ24295 voltage regular which would theoretically allow me to use LiPo batteries for my remote stations.

My current usage of Particle’s products alone prevents this because:

  1. I have some sensors which are 5V-only and there’s no boost circuitry on their boards;
  2. My sites are in cold climates and must be able to turn off LiPo battery charging under 32F to not damage the battery, and the broken Particle software ruins this ability.

The imp006’s combination of a LiPo connector, a built-in temp sensor, and a 5V boost regulator is HIGHLY promising to me. I currently have heavy/expensive 12V solar + 12V SLA + external solar charger + external 12v-5v regulator setups which I am looking to simplify.

But the 5V boost regulator is not working for me:

  1. I take a brand new imp006 Breakout Board from the box;
  2. I take and connect a LiPo measured at 4.0V open circuit;
  3. I solder 1-2 together on JP-E (W10 left unsoldered);
  4. I jump “1-2” for JP-A through JP-D.

However, the 5V pin reads “3.8V” which is the same as the LiPo voltage under load. No boost.

When is the BQ24295 boost output enabled? Is it not automatically on, as the JP-E jumper text would indicate? The BQ24295 datasheet says, “The boost mode is activated when the OTG pin is High, REG01[5]= 1, and no Input source is detected at VBUS.” What is the imp006 Breakout Board doing wtih the BQ24295 OTG pin?

Thank you.

Further and related, the following statement from the reference page seems to be contradictory to what is written on the board.

Concerning solder jumper JP-E, it is written:

“The Click 5V line receives power via jumper JP-E. Set this to position 1-2 to either drive the 5V from the Breakout Board’s USB input, or to drive the Breakout Board from a suitable Click. By default, 5V power for the Click comes from the Breakout Board’s PMU, unless the latter is charging. Put the jumper on JP-E pins 2 and 3 for the default behavior.”

However, the board itself says:
“JP-E Jumper
1-2: 5V U1 Boost
2-3: 5V USB Boost”

The page suggests that JP-E being set to 1-2 takes “5V from the Breakout Board’s USB input”.

The board silkscreen text contrarily suggests JP-E being set to 1-2 takes “5V” from “U1 Boost”, as opposed to the “USB input”.

Which one is correct, and does this relate to my inability to see the 5V boost output with a LiPo connected?

Thank you.

JP-E is 1-2 for power from the PMU - ie, U1 (can ONLY be used if the device is battery powered from a 3.7v Li-Ion cell - if it’s charging, this is not available)
2-3 is power from the 5v USB connector. There should be no “boost” written on the board.

Seems like the docs need correcting.

If you are using 1-2 to boost from Li-Ion to 5v, you need to drive the OTG pin on the PMU (U1) high. You do this by soldering link W10 and driving pinYC high - see schematics. You’ll also need to ensure that REG01 bit 5 is high, though it is by default (see BQ24295 datasheet)

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