BQ25570: Can BQ25570 work for 3 battery in series?

Betty Guo

Part Number: BQ25570

Hi Team,

my customer use solar as input source, the input voltage is 2.5V, and output is 3.6V for 3 battery series, each battery is 1.2V. the battery chemistry is NiMH.

I promote BQ25570 to customer, but I found it used for signal cell, so I want to know does it can work in customer application?

if not, do you have any low cost solutions can share with me.

thank you.

over 7 years ago

0 Jeff F over 7 years ago

TI__Guru**** 166456 points

Betty,

Yes. As long as VIN stays below VBAT_OV, the charger can charge multiple cells. The single cell comment refers only to LiIon.

0 Betty Guo over 7 years ago in reply to Jeff F

TI__Expert 7300 points

Hi Jeff,

thanks for your fast reply.

I have one more question is which one will power system load when the V_STORE higher than VBAT_OV or when the battery is full? battery or V_STORE? as datasheet show device will disable booster charger when the V_STORE higher than VABT_OV.

look forward your reply.

thank you

0 Jeff F over 7 years ago in reply to Betty Guo

TI__Guru**** 166456 points

VSTORE is connected to VBAT through a P channel MOSFET. Even when the MOSFET is off, the MOSFET body diode clamps VBAT=VSTORE-~0.6V. VBAT_OV setting actually sets the maximum voltage for VSTORE.

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BQ25570: Can BQ25570 work for 3 battery in series?