Can the MP2672GD charge a 2S2P 7.4V 6000mAh Li-polymer battery pack with dual NTCs?

Battery Management
1

I have four 3.7V 3000mAh Li-polymer cells.

  • Two cells are connected in series → giving a 7.4V, 3000mAh pack.

  • Another two cells are connected in series → giving another 7.4V, 3000mAh pack.

  • These two 7.4V packs are then connected in parallel → resulting in a 7.4V, 6000mAh (2S2P) battery.

Now, I want to use the MP2672GD charger IC to charge this 2S2P battery. Each 2-cell series pack has its own NTC for temperature monitoring, but the MP2672 has only a single NTC input. So i just add a circuit with op amp Comparator and analog multiplexer to detect hottest NTC belongs to which battery, Please review my attached schematic. Thanks in advance

mp2672gd
mp2672gd888×688 63.7 KB

2

Hi,

Your schematic overall looks correct. However, I have a couple questions regarding your application. Do you plan on alternating between host control and standalone mode? Furthermore, do you wish to alternate between battery cell balancing and disabling balancing? (With regard to CV and MID pins respectively).

Regards,

Tyler

3

Hi Tyler,

Thanks for your reply. Yes, we are planning to alternate between host control and standalone mode using the CV pin, and also test both with and without battery cell balancing to analyze the battery performance.

I would like to clarify my doubts:

  1. Can I use the MP2672GD to charge a 2S2P battery pack?

  2. Will my NTC sensing circuit using op amp comparator and analog multiplexer work properly with the MP2672GD? Thanks in advance

4

Hi,

  1. Yes, the MP2672GD should work for your 2S2P battery arrangement. Just make sure 2A during constant current charging will suffice as your batteries will also be in parallel.
  2. You will need to confirm your multiplexer feeds the correct NTC voltages into the charge IC based on the datasheet threshold values.
1 Like
5

Hi Tyler,

 Kindly share the layout file for EV2672-D-01A, which is useful for our design BMS circuit.
6

Hi,

Please submit a ticket as we’ll need more information:

Best,

Tyler

7

hi Tyler,

I have a doubt about the MP2672GD IC. When the battery is not connected, I measured the system voltage (VSYS) as 8.4 V, but according to the datasheet, the system regulation minimum voltage is VBATT_PRE + VTRACK = 6.7 V. Why am I getting 8.4 V? When I connect a 7.52 V battery, the system voltage becomes 7.5 V (same as the battery voltage).

8

Hi,

This is likely because your CV resistor is set to 30k, which sets your CV voltage to 8.4V.

Best,

Tyler

9

thank you for your response