MP2796 split CHG and DSG path

Battery Management
1

Hello,

My team and I are currently reviewing the MP2796 for a custom 12S Li-ion BMS solution.
We would like to know if this part is suitable for a split Charge and Discharge path, like in the TI part we are currently trying to replace.

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This would allow us to reduce the BOM cost by downsizing the CHG mosfet.
And if it is possible, how should the VMID pin of the MP2796 be connected ?
If you have any idea or implementation example, we would be very grateful.

Robin Perdreau

2

Hello Robin,

The MP2796 supports split charge and discharge paths as it allows for independent management of charging and discharging currents. This would also help with thermal performance which would in turn extend battery life.

In regard to the VMID pin, it is the protection MOSFET middle point where it connects charging and discharging paths to the internal charge pump for control and monitoring functions. You should connect VMID to the midpoint of your 12s battery string as seen in the following image (MP2796 datasheet page 2, more details on page 117 regarding necessary discrete components and connections that you will think is very useful).

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Ensure that this pin is tied to a decoupled connection between your 6th and 7th cells in series. Use filtering ceramic capacitors as appropriate between 1uF and 10uF and be sure they are close to the VMID pin to ensure node stabilization.