MC33772C 4cell configuration

[robertoschembar]

Hi team,

I want use MC33772C for 4 cells configuration (cell 3 and 4 not connected). In the safety manual (par. 8.1.1 or 13.2.2 of the datasheet) seems that LPF could be removed only for CT4 and all Rbal and Rbalc must be present. But in this article for MC33772B seems that also LPF for CT3 is possible to remove.

Moreover I would to remove Rbalc (connected to CB4:3) and Rbal (connected to CB3 and CB4), and all these pin short to CB2, so Rbal for CB2, terminated these pin too.

If this is not possible, is it necessary that Rbal should be the same as the used cells or could be the same value, but with less power?

thanks

[TomasVaverka]

Hi Roberto,

I would recommend you to take a closer look at our AN12536 which explains how to arrange LPF for MC33771/MC33772 when using less than 14/6 cells. 

You can download the AN12536 from this website. 

Please make sure you are signed in to nxp.com and select Secure Files. If you do not see the AN12536, please click on "Request additional access" or edit your secure access rights by going to My NXP > Profile. 

In case of any problems with downloading the AN12536, please contact directly our DocStore Support team via support.docstore@nxp.com. 

Best regards,

Tomas

[robertoschembar]

Hi Tomas,

Using the Filter type B for MC33771 (fig 2 in AN12536) is OK for Safety with MC33772C?

Best regards,

Roberto

[TomasVaverka · Accepted solution]

Hi Roberto,

Yes, please look at Fig. 3 of the same application note: it is aimed at MC33772B, but can be used for the MC33772C as well.

Best regards,

Tomas