BQ25120A: Falling Vin Voltage

Part Number: BQ25120A

Tool/software:

What is the expected behavior of the device if I have a falling VIN voltage with a battery connected? I have two VIN sources that will go from 5V to 0V in ~20s and ~3s ie very slow discharge

25 days ago

0 Juan Ospina 25 days ago

TI__Genius 15925 points

Hi,

The expected behavior is that, as the VIN falls below 4.6V (VINDPM) then no more current will be pulled from VIN. Once VIN falls below sleep then /PG will be low and VIN won't be used for power. Once VIN falls below UVLO the device will not recognize VIN as present. Depending on the state of the device, the IC will switch to battery power after the device falls below Sleep or UVLO.

Best Regards,

Juan Ospina

0 JM 25 days ago in reply to Juan Ospina

Prodigy 40 points

What states of the device will cause it to not switch to battery power after UVLO?

0 Juan Ospina 25 days ago in reply to JM

TI__Genius 15925 points

A shipmode entry may cause this. Alternatively if the battery voltage is below BUVLO then the device will just power off.

Best Regards,

Juan Ospina

0 JM 22 days ago in reply to Juan Ospina

Prodigy 40 points

So for a slow draining VIN source, while on battery, should not cause the PMIC any issues?

0 Juan Ospina 22 days ago in reply to JM

TI__Genius 15925 points

Hi,

As long as the battery is above BUVLO, the device should switch to battery power.

BR,

Juan Ospina

0 JM 22 days ago in reply to Juan Ospina

Prodigy 40 points

Will the PMIC be in a fault state as per the state diagram provided in the datasheet?

0 Juan Ospina 22 days ago in reply to JM

TI__Genius 15925 points

it'll report a VIN_UV fault, but the device will operate in the HIGH_Z or ACTIVE BATTERY state.

Power management

Power management forum

BQ25120A: Falling Vin Voltage