BQ24160: BQ24160 d+/d- detected issue

li jongyann

Part Number: BQ24160

Hi,
In my application I am using D+/D- detection and I set the D+/D- is short.
Battery =3.8V
My step is to connect the battery first and then connect the USB port.
Then read BQ24160 Register 0X02
Sometimes USB input current limit is set to 1.5A
Sometimes USB input current limit is set to 0.1A
Is this a normal phenomenon?

Thanks!

over 7 years ago

0 Jeff F over 7 years ago

TI__Guru**** 166576 points

When D+=D-, USB input current limit should always be set to 1.5A. Can you monitor VBUS and D+/D- on a scope at plug in? Does VBUS come up very slowly? Is there a glitch at power that affects D+=D-?

0 li jongyann over 7 years ago in reply to Jeff F

Prodigy 90 points

Hi Jeff,

When D+=D-,
I measured the VBUS rise time using the BQ24160EVM.
VBUS rise time is very fast <1ms
Figure 1 USB current limit 1.5mA (battery=3.4v)
Figure 2 USB current limit 0.1mA (battery=4.2v)
When the battery voltage is about 3.8v,
Sometimes USB input current limit is set to 1.5A
Sometimes USB input current limit is set to 0.1A
please help,
Thank you

0 Jeff F over 7 years ago in reply to li jongyann

TI__Guru**** 166576 points

When you attach the battery with >3.6V, have you changed the VBATREG I2C register from 3.6V default? If not, the charger detects battery OVP and therefore a fault. In that case, D+/D- detection does not occur and input current limit stays at its default of 100mA as a safety measure. You will have to write to increase the VBATREG register and then write to the register that forces D+/D- detection.

0 li jongyann over 7 years ago in reply to Jeff F

Prodigy 90 points

Hi Jeff,
thank you very much,
Ask a question again,
Will only connect the battery,
Need to set VBATREG and clear watch dog? (when discharging)

0 Jeff F over 7 years ago in reply to li jongyann

TI__Guru**** 166576 points

In battery only mode (HiZ), the BATFET turns on tying the battery to SYS. When the watchdog expires, VBATREG resets to 3.6V and the charger will report battery OVP. You do not need to change the VBATREG setting while the charger is in HiZ mode.

0 li jongyann over 7 years ago in reply to Jeff F

Prodigy 90 points

Hi Jeff,
I have no other questions.
Thank you

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BQ24160: BQ24160 d+/d- detected issue