BQ51025 AD - AD/EN doesn't work properly

support cintech

Other Parts Discussed in Thread: BQ51025

I'm currently using an ECH8654 PMOS switch for AD to VOUT connexion while using a DC plug. But i've got a strange behaviour :

If I put a DC plug of more that 12V (i.e. 12.3V or 13V), it looks like AD/EN doesn't work properly and is just following AD voltage so that switch never goes on and AD plug looks disconnected.

When I'm using <12V DC plug, everythings looks fine.

Is there any good reason for that behavious ?

Note : I'm using a 2S schematic such the one that is present onto datasheet.

Thanks for help

over 9 years ago

0 support cintech over 9 years ago

Prodigy 125 points

*bump* ? no-one got that problem ?

Regards

0 Bill Johns over 9 years ago in reply to support cintech

TI__Guru* 76076 points

Hi Cintech
Sorry for the delay getting to your question.
The AD-EN / AD circuit has a clamp circuit that will keep AD-EN 4 to 7V below AD.
But we do not expect the two to be the same voltage above 12V. I will run additional test over the next couple of days.

0 support cintech over 9 years ago in reply to Bill Johns

Prodigy 125 points

Hi Bill, do you have any more informations for me about that problem ?

0 Bill Johns over 9 years ago in reply to support cintech

TI__Guru* 76076 points

The circuit is operating correctly.

With no power on the wireless power IC the OVP ckt is active at 12V.

When the IC is powered OVP ckt is active at a higher level.

The bq51025 needs about 3V on Rect pin to turn on, UVLO is about 2.7V.

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BQ51025 AD - AD/EN doesn't work properly