Part Number: BQ40Z80
Hi,
I am adopting a Bq40Z80 circuit of 3 parallel mosfets in CHG/DSG, so I'm trying to increase the driving efficiency of Bq40Z80's pin CHG/DSG.
I'm thinking about two things :
1. CHG/DSG FETs gate resistors selection:
In EVM, CHG FET resistor is 1kΩ, and DSG FET resistor is 4.02kΩ.
In Datasheet, there is only few descriptions about it as shown followed.
So, could I know what is based on about selecting the resistors? Is it usful that selecting a smaller resistor to increase the driving efficiency of PIN CHG/DSG?
2. PBI capacitor C20 selection
There is a phenomenon that the bq40z80 was shutting down when trying to enable the 3 parallel FETs.
But after changing the capacitance on the PBI pin (2.2uF, C20 on the EVM) from 2.2uF to 8.8uF, it can be able to switch the FETs fine.
Could I know are there some logical reasons?
Thank you very much for your help!!
Best Regards,
Iris Weng
Iris Weng