Disabling NTC pin in MP2672

Battery Management
1

Hello,
I have 2 questions regarding this IC.
1- Is it okay to disable the NTC Pin in MP2672? and if it’s okay, how to disable it?
2- The system load current is up to 8A, but SYS pin maximum current is 2A, So can I disable this pin and connect the load directly to the battery terminals?
Thanks.

2

Hi abdallahwagdy70,

Thank you for contacting the MPS Forum.

  1. Yes, you can essentially disable the NTC function by fixing the voltage of the NTC pin with a voltage divider. This would essentially fool the device into thinking the temperature is always in the correct temperature range.

  2. Based on the datasheet, it looks like you can potentially put the device into suspend mode to disable the system boost function. I think this will functionally achieve disabling the SYS pin. You can read more about this on page 25 in the datasheet. Note that this requires the ability to write to the device in I2C.

Please let me know if you have any other questions.
Thanks,
Brendan Schoemehl
Field Applications Engineer
Monolithic Power Systems | MPS Now

3

Hi mpsnow.brendan,
Thanks so much for replying to my questions.
So regarding the second point, according to your answer, this means there’s no way to disable the SYS pin in standalone mode (Hardware way)?
Also if I disable it using the suspend mode to disable the system boost function, I think the load current will also pass through the Battery FET (According to page 25 in the datasheet). So my question is, If we disable the SYS pin and connect the load directly to the battery terminals, why the current still have to pass through the battery FET?
Thanks for your help.

4

Hello abdallahwagdy70,
There is a single FET from the battery to SYS, and the body diode is oriented such that charging can be turned off, but current can still flow from the battery to SYS through the diode. Other products may have back-to-back FETs to block that flow.
Regards,

5

To add on here, I would say yes there is no way through hardware/standalone to disable the SYS pin. I believe this can only be done through software.

Thanks,
Brendan

6

Hello James.P and Brendan,
So, if I disabled the SYS pin through software, Is there anyway to put a load with continuous current 8A?
Thanks,
Abdallah Wagdy

7

If you draw directly off the battery, you could provide a load of 8A if your battery is able to handle that much current draw. You just have to draw externally from the device and not use the system output of the device itself.

Thanks,
Brendan

8

Hello mpsnow

In my design I kept NTC pin to NC (not connected) and due to that we are not able charge battery using IC even in standalone mode.

Is there anyway to use this IC without NTC pin usage?

9

Hello MPS team

Can someone help me for my query ??

I want to use Battery charging IC without NTC pin usage

10

Hi cvsharma3,

This was addressed earlier in the thread, but to reiterate the NTC pin should not be left as NC. Instead, you should fix the pin to an appropriate voltage with a voltage divider resistor network in order to disable the NTC function.

Thanks,
Brendan