BQ24120: Is there a safe operating condition without input power?

Felix Hirzel

Part Number: BQ24120
Other Parts Discussed in Thread: BQ25606

We're hoping to use this chip for a new design in a single cell LiPo battery charger. Having read both the data sheet and the application guidelines, we're not certain as to the safe operating conditions with a permanently connected battery but only sporadically connected input power. For instance, is the state of the CE pin important while there is no input power? Can the chip be operated at all under these conditions, i.e. battery connected but no input power.

A quick test seems to suggest that the chip is not particularly happy that way.

Please advise. Thank you.

over 5 years ago

0 Jeff F over 5 years ago

TI__Guru*** 144020 points

Hi Felix,

This charger should operate safely in SLEEP mode with only battery connected. The CE pin should be disabled when input power is removed. In what ways does the charger appear to be unhappy?

Also, could provide more info on your charging requirements, for example battery capacity, maximum input voltage, max charge current, max system load? There might be a newer charger that better fits your requirements.

0 Jeff F over 5 years ago in reply to Jeff F

TI__Guru*** 144020 points

Hi Felix,

I haven't heard from you in a while. Do you still have questions?

0 ezhao over 5 years ago in reply to Jeff F

TI__Genius 10240 points

Hi Felix,

We haven’t heard back from you. We are assuming you were able to resolve the issue. If not, just post a reply below or create a new thread if the thread has locked due to time-out.

0 Felix Hirzel over 5 years ago in reply to Jeff F

Prodigy 20 points

Hi Jeff

Sorry, missed your earlier replies. Yes, the problem was a soldering issue. Thanks for your help, though.

And in answer to your question, this application needs a single LiPo cell of about 1000mAh, and a charging current of less than 0.5A. The BQ24120 works great but if there is a newer alternative, especially a less expensive one, that would be great.

Kind regards,

Felix

0 Jeff F over 5 years ago in reply to Felix Hirzel

TI__Guru*** 144020 points

Felix,

Great to hear that you solved your issue! The newest standalone switching charger we have BQ25606. It includes power path feature and integrated sensing resistor.

Power management

Power management forum

BQ24120: Is there a safe operating condition without input power?