BQ25601: BATFET defualt is off, Vsys(15,16pin) is 0v when only battery present without a vbus plugin

user5147365

Part Number: BQ25601

please find my schematic in attachment.

the 15/16 pin has no output when the vbus is absent, i measured /QON=1.37V, REGN=0V,/CE=0V,TS=0V

Sometimes Vsys output is normal when plugged a 5v charger and then plugged out, in this stae i measured /QON=2.65V,REGN=0V,TS=0V,/CE=0V.

I do not know why?please hurry help me, thank you very much..BQ25601-SCH.pdf

over 3 years ago

0 Ning T over 3 years ago

TI__Mastermind 46671 points

Hi,

What are your test conditions such as VBAT (voltage at BAT pin), IBAT, VSYS, ISYS and test procedures? Could you please provide all register values of the charger when VSYS=0V?

Please visit https://e2e.ti.com/support/power-management/f/196/t/890624 for I2C controlled BQ2560X: Schematic Review and PCB Layout Design Tips.

Thanks,

Ning.

0 user5147365 over 3 years ago in reply to Ning T

Prodigy 230 points

thanks for your reply,

i measured these pins after insert a 4.2v Li battery uesd multimeter. when vsys=0v, the system is in off state,how can i get the register value? do you mean the register value when the system powered on?

0 user5147365 over 3 years ago in reply to user5147365

Prodigy 230 points

hi ning ,

did you find any problem in my schematic? if hardware is ok, i will try to solve this issue from software. thank you!

0 user5147365 over 3 years ago in reply to user5147365

Prodigy 230 points

hi ning,

i think i found the reason, the capacitance is too large on vcc_main(15.16pin) net, i remove c144 c131 c141 then vcc_main has voltage same as the battery. how can i caculate the inrush current through batfet to the capacitances? does that exceed 6A so cause the batfet tured off?

0 Ning T over 3 years ago in reply to user5147365

TI__Mastermind 46671 points

Hi,

Referring to 8.3.10.4.3 System Over-Current Protection, When the system is shorted or significantly overloaded (IBAT > IBATFET_OCP) and the current exceeds BATFET overcurrent limit, the BATFET latches off.

Thanks,

Ning.

0 user5147365 over 3 years ago in reply to Ning T

Prodigy 230 points

but i did not find the time duration for exceeding the threshold 6 A?

theoretically, the inrush current to the capacitor all will exceed 6 A, the difference is that the time duration , it that right?

0 Ning T over 3 years ago in reply to user5147365

TI__Mastermind 46671 points

Hi,

If the battery discharge current is greater than IBATFET_OCP, the BATFET latches off.

Thanks,

Ning.

0 user5147365 over 3 years ago in reply to Ning T

Prodigy 230 points

OTG? i do not need this function.

0 Ning T over 3 years ago in reply to user5147365

TI__Mastermind 46671 points

Hi,

The battery will discharge in both OTG mode and supplement mode. As long as the battery discharge current is greater than IBATFET_OCP, the BATFET latches off.

Thanks,

Ning.

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BQ25601: BATFET defualt is off, Vsys(15,16pin) is 0v when only battery present without a vbus plugin