MC33771B or MC33772B

[Patrick_Pavle]

Dear Community,

i have a battery module with 12 cells where 6 are connected in series and these are then connected in parallel.

i can't physically access the hardware from the battery so i have a black box.

The nominal voltage of the battery is 21.6V and the cell voltage is 3.6V because there are 2 cells in parallel.

How can I find out via software whether it is a MC33771B or MC33772B that is inside? 

And what is the minimum number of cells required to operate the MC33771B? So what is the smallest possible and why? 

BR, Patrick

[JozefKozon]

Dear Patrick,

please refer to the Comparison Table in the MC33771B product page. 

Minimum numbers of cells for the MC33771x is 7, maximum is 14. Minimum numbers of cells for the MC33772x is 3, maximum is 6.

Please make sure, that you do not exceed the Cell input voltage range per channel. 

How can I find out via software whether it is a MC33771B or MC33772B that is inside?

[A] You can check the OV_UV_EN register, address 0x08. By default the content of this register in the MC33771B is 0b0011 1111 1111 1111, while in the MC33772B it is 0b0000 0000 0011 1111. Please refer to the Table 50. in both MC33771B and MC33772B datasheets. 

With Best Regards,

Jozef

[Patrick_Pavle]

Dear @JozefKozon,

can i also check it by trying the register MEAS_CELL14, address 0x33.
With the MC33772B there should be no response, right?

BR, Patrick

[JozefKozon]

Dear Patrick,

yes, you can also try to read the MEAS_CELL14, address 0x33. There will be actually response if you try to read it on the MC33772B, but will be always the same 0x0000. 

With Best Regards,

Jozef

[Patrick_Pavle]

Dear @JozefKozon,

what would be the response from the mc33771b if there is no cell connected?

BR, Patrick