Is "No battery plugged" detection possible? (MP2723A)

Battery Management
#1

Hi,
I’m integrating the MP2723A into one of our products and I noticed an odd behaviour.
I’m working on the integration using the evaluation kit (EV2723A-QC-00A)

When using it without any battery (VBATT) connected, the charging state seems to go a little bit crazy because it constantly flip-flops from charging to fully charged.

Is there any way I can detect there’s no physical battery connected to ignore these strange state changes (or maybe even stop checking the charging state)?

All I could think of is checking the ICHG ADC value. When that’s 0 and the state is charging
, I assume there’s no battery. It kinda works, but I’m not very comfortable with this method.

Thanks in advance

Toni

#2

Hi toni.barrera,

I’m looking into your question and will post an update soon.

#3

Hi Toni,

In a real application, when there is no battery inserted, the NTC will also be invalid.
In this case, we can read the status as: NTC float. This also means “no battery” state.
And in this condition, VBATT is 0 and VSYS is regulated to constant VSYSMIN.
You can remove RT2 in the EVB to see such state.

#4

Hi Bryan,
I think I’m missing something in your explanation.
Currently, I have EVB without a battery and I’m powering via USB.
The ADC values I’m getting are:
VBATT: 3940mV
VSYS : 4040mV
NTC : 49%
VIN : 5100mV
ICHG : 0mA
IIN : 79mA

When checking REG0Ch I’m getting 10110001
NTC float value is 0, so apparently the module is not detecting “NTC float” state

In addition, you say that VBATT should be 0 is this “NTC float” state, but clearly that’s not the case

Am I interpreting something incorrectly?

BR

Edit: Just for the record I have not yet removed RT2 because I’m not sure what will happen to the EVB general behavior when that’s not present.

Toni

#5

Hi,
So only way to understand if battery is plugged to use NTC on battery, right? Because in our application there is no NTC presented. When we remove RT2, VBATT is 0 and status is not charging but in that case charging also dont start because of floating NTC.

Thanks.