BQ25570EVM-206: Efficiency of BQ25570 EVM is not correct with datasheet

Giao Thuc

Part Number: BQ25570EVM-206
Other Parts Discussed in Thread: BQ25570

Deal Ti

I am working with BQ25570 EVM-206, setting MPP = 80% ( Voc_samp = 80%) . Input is a GaAs single crystallize ( Voc = 0.94 V, Isc = 16.04mA) at 16600 lux from LED light and I get the result at VBAT ( VBAT = 4.19 V, IBAT = 5.16mA). So the output power larger than the input power, exceeding 100%. Could Ti give me some explanation about this problem ?

Thanks.

H.Thuc

over 6 years ago

0 Jeff F over 6 years ago

TI__Guru**** 166416 points

Hi Giao,

Measuring efficiency with this device is very difficult due to the low value, pulsing input and output currents. Below are two application notes that explain the issues and provide one measurement method that works:

www.ti.com/.../slyt558.pdf
www.ti.com/.../slua691

Regards,
Jeff

0 Giao Thuc over 6 years ago in reply to Jeff F

Prodigy 30 points

Thanks for your help!

Best Regard,

Thuc

0 Giao Thuc over 6 years ago in reply to Jeff F

Prodigy 30 points

Hi Jeff,
Could you give me the raw data about Charger Efficiency vs Input Current from Figure 1 to Figure 12 in BQ25570 datasheet ?
If you have the resemble data with VSTOR = 4.2 V, please send to me. Thanks you very much !
My email : ghthuc24040511@gmail.com

Best Regard,
Thuc

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BQ25570EVM-206: Efficiency of BQ25570 EVM is not correct with datasheet