BQ25886EVM: can't entry fast charge

Jeff YANG

Mastermind 7795 points

Part Number: BQ25886EVM
Other Parts Discussed in Thread: BQ25886

Hi,

My customer used BQ25886EVM but can't entry fast charge.

Our test condition as below.

1. Set ILIM to maximum.

2. Set ICHGSET to maximum.

3. Provide 5V to VBUS.

But battery charger current only ~200mA, seems in pre-charge mode, but battery voltage ~7.2V,

Is there any possible to let BQ25886 in pre-charge mode?

Thanks!

Jeff

over 4 years ago

0 Jeff F over 4 years ago

TI__Guru**** 166136 points

Hi Jeff,

Can you provide a scope shot of VBUS and VBAT, close to IC pins, and the SW node? If you increase the voltage to VBUS, does the charge current increase?

Regards,

Jeff

0 Jeff YANG over 4 years ago in reply to Jeff F

Mastermind 7795 points

Hi Jeff,

I found because my D+D- have no short together cause can't entry fast charge.

But I still have another question is about "8.3.9 Input Current Limit on ILIM Pin",

it mentioned when VILIM lower than 0.8V, will used other calculation Iin=KILIM*VILIM/(RILIM*0.8),

How do I know VILIM voltage is? it depend on from?

Thanks!

Jeff

0 Wyatt Keller over 4 years ago in reply to Jeff YANG

TI__Guru** 105640 points

Hello Jeff,

VILIM is the voltage on the ILIM pin, it is based on your resistor selection to set the input current value. It will change depending on your RILIM resistor.

The section you're referring to is describing how the voltage on ILIM can be used to find the input current, the input current is not always the maximum you select, it can be lower if the charger does not need all the power that is available on the input.

Sincerely,

Wyatt Keller

Power management

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BQ25886EVM: can't entry fast charge