BQ25125: Detecting Hi-Z mode

James Sullivan73

Prodigy 175 points

Part Number: BQ25125

Tool/software:

I may be missing something - BUT...

In table 9-1 the x4 states of the device which depend on the CD input and Vin are documented.

But - in order to know which state I am in - I need to know if Vin > Vuvlo.

I obviously know the state of the CD pin.

However - there is no way to measure Vin - if in Hi-Z mode - which draws the lowest current (1.35ua vs 6.8ua)

And in Hi-Z mode the I2C does not work .

Neither does the PG pin.

So - I am looking for the best practice for determining which state I am in.

.js.

6 months ago

0 Juan Ospina 6 months ago

TI__Genius 15185 points

Hi James,

If /CD is Low and VBAT is present, and I2C communications are not available, this is an indicator of HiZ mode. HiZ depends on VBAT being present, VIN being not present, and /CD being low.

- If VBAT was not present then the device rails would be disabled and the host controller would be off.

- If /CD was High we would be in Active BAT mode which does enable I2C, it is in a known low state so this possibility can be discarded.

- If VIN was present then I2C should be available, regardless of /CD.

Best Regards,

Juan Ospina

+1 James Sullivan73 6 months ago in reply to Juan Ospina

Prodigy 175 points

So you are saying that I should test if I2C is available as a qualifier.

Will do.

+1 James Sullivan73 6 months ago in reply to Juan Ospina

Prodigy 175 points

It turns out that the PG-low (power good) always works.

Power management

Power management forum

BQ25125: Detecting Hi-Z mode