BQ76952EVM: BQ76952EVM

Hi Subhash,

It sounds like the issues listed are all the same - the FETs are toggling on and off. Can you capture this behavior on a scope and share your schematic? Are you using multiple FETs in parallel? Can you also share your device settings? You can do this by clicking the Export button in the BQStudio Data Memory screen to save a .gg.csv file.

Best regards,

Matt

Hi Matt Sunna,

Thanks for your reply,

Yes, we are using  FETs in  parallel configuration for charging and discharging.

We have already  provided you device setting in the  xls format.

If you need something else please revert.Advance_BMS_Schematics_page1_2.pdf

I will send the scope capture and share my schematics.

NOTE:- The scope  used  to capture  this waveform is TI_SPI_B3_SCD_120A0000.rar. and  waveform can be viewed in Xviewer utility.

thanks and regards

Subhash dhyani

Hi Subhash,

Thanks for sending your schematic. I think there are some issues in your FET circuit that may explain the FETs not being able to switch properly. The 10nF capacitors will add lots of additional capacitance making it difficult for the gates to switch quickly. The 3M resistors are small and since there are 4 in parallel it will create an equivalent 750k which will drain the charge pump. 

I suggest following the example in the Multiple FETs app note (https://www.ti.com/lit/an/sluaa09/sluaa09.pdf ). In this case, remove the 10nF caps and remove the 4 resistors and place only 1 10M resistor to see if it helps. The app note also gives some guidance on the charge pump capacitor value which you may want to adjust.

Best regards,

Matt

Hi Matt Sunna,

Thanks for your suggestions.

I will implement your suggestion and let you know if it improves.

Thanks and regards

Subhash Dhyani