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BQ25570EVM-206: Basic hookup and jumper settings

Part Number: BQ25570EVM-206

I have 3 components to connect. 

1) PV Panel, 4V 75mA 

2)  BQ25570EVM-206

3) LiPo Battery, 3.7V at 100mAh

My questions:

Q1: Where do I connect the battery?  VBAT (J8), VSTOR (J5)

Q2: What are the jumpers settings for basic operation?

Q3: What is VSTOR?  When is it used?

Q4: Is VOUT just a regulated output to supply power to other components on a user's PCB?


  • Oops.  Typo. The battery is 1000mAh.  It also has a built-in protection circuit like many LiPos do.
    Q5:  With the battery's protection circuit interfere with charging when the battery has a low charge such as 3.5V? 

  • HI Chris,

    Regarding Q1, the battery is typically connected at VBAT, J8.

    Regarding Q2, the EVM jumpers are in the recommended positions for charging a LiIon battery up to 4.2V and providing a 1.8V output out of the buck converter.  The input related jumpers (JP1 and JP4) are configured for a solar panel input with MPP = 80% of the panel's VOC.  This is a boost only charger so VOC*80% must be less than VBAT_OV=4.2V.

    Regarding Q3, VSTOR is intended to be connected to the system voltage.  There is a FET between VSTOR and VBAT that provides under-voltage protection in case the battery doesn't have internal protection.  Since your battery pack has protection, you can short VBAT=VSTOR.

    Regarding Q4, yes.

    Regarding Q5, no.  This charger only provides constant voltage charging. Once the voltage at VSTOR reaches VBAT_OV=4.2V as set by the OV resistors, charging stops.



  • Hi Jeff,

    Thanks for the reply.  I'm unclear what the Jumper settings should be.  I've attached a photo of how the board is currently set up.  Does this look correct?  An ampmeter placed in series with battery shows no current.   The same meter shows ~80mA when put in series with the PV panel.

  • Hi Chris,

    If the shunt is installed on JP6, please remove it because VOUT_EN is tied to GND by JP3.  Regarding the ammeter, please ensure that it is not set for autorange as that causes issues for the charger.  Other than that, the EVM should work for you.



  • Hi Jeff,

    JP6 shunt was not present however I was using an auto ranging multimeter.  I dug up a non-auto ranging meter and now can see current flowing into the battery!  Thank You!  What is it about auto ranging meters that would cause them not to work on the battery side but function on the PV panel side?

    Does the FET, mentioned in your Q3 response, open when VSTOR gets below a certain voltage, to protect the battery (if it didn't have a protection circuit) from being drained too low?  What is that level and can it be adjusted?  Because our (current) battery has a protection circuit, do you recommend tying together VBAT=VSTOR?  What is the benefit of doing this? 

    Thanks for answering the other questions too.  In the past we used another mfg's charging IC that wouldn't charge batteries that were drained down to around 3.4V.  We switched to batteries without the protection circuit to resolve the issue.  



  • Hi Chris,

    When trying to change ranges, the meter goes high impedance, preventing current flow and causing VSTOR to hit 4.2V the regulation point.

    The FET between VSTOR and BAT opens when V(BAT) < 2.1V.  That level is not user changeable.  The FET is max 1ohm impedance so shorting it out increases charger efficiency.  Also, that FET doesn't support hot plugging a battery, i.e. the voltages at VSTOR and BAT must be < 100mV when attaching a battery or the FET does not close.



  • Such good information.  Thanks Jeff!