BQ25570: is it possible to get 3.3v output from BQ25570 Vout? even battery voltage is Less than 3v?

Karthik A1

Prodigy 30 points

Part Number: BQ25570
Other Parts Discussed in Thread: BQ25505, TPS61170

I am looking solar Harvester Power Management IC like BQ25570. But, they giving 3.3v Buck converter output.

So, is it possible to get 3.3v output from BQ25570 Vout? even battery voltage is Less than 3v?

if not possible, Please suggest an IC which can provide 3.3v Buck/Boost output even battery voltage is Less than 3v.

over 4 years ago

0 Jeff F over 4 years ago

TI__Guru*** 143950 points

Hi Karthik,

Unfortunately, no. The BQ25570 VOUT output is from a buck converter and would require a slightly higher voltage than 3.3V to provide 3.3V output. Can I recommend BQ25505 followed by BQ63024 integrated solution or TPS61170 configured as a SEPIC converter (d/s figure 19 page 21)?

Regards,
Jeff

0 Karthik A1 over 4 years ago in reply to Jeff F

Prodigy 30 points

But, Even we using bq25505. there is no buck-converter.so Have to use external buck/boost right?

0 Jeff F over 4 years ago in reply to Karthik A1

TI__Guru*** 143950 points

Karthik,

The BQ25505 will boost charge from your solar panel (with MPP <4.2V) to the battery. Then the buck-boost can provide the 3.3V even when the battery is below 3.3V.

Regards,

Jeff

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BQ25570: is it possible to get 3.3v output from BQ25570 Vout? even battery voltage is Less than 3v?