BQ76952: Charge Pump Voltage is Decreasing in Charging & Dis-Charging

Chand Padaliya

Part Number: BQ76952

TI Support Team,

I Have Developed a hardware who have 6 Charge MOSFET's in Parallel & 6 Discharge Mosfet's in Parallel.

Observed that When we Perform Charge & Discharge Cycle.

Charge Pump Voltage will Reduce.

Current Charge Pump set to 11V.

But it come down to 8V or 7V.

Why this is happening?

is it acceptable ?

for you better understanding attaching snap of implemented circuitry & Used MOSFET's..

MOSFET-JMSH1004BC(E)_Rev2 2.pdf

Thanks ,
Chand Padaliya

over 3 years ago

0 Luis H. S. over 3 years ago

TI__Mastermind 42060 points

Hello Chand,

That may happen depending on the number of FETs you are trying to drive.

It may be that your charge-pump (CP1) capacitor (C18) is too small, I see you are using many MOSFETs in your design. The charge-pump capacitor must be sized appropriately based on the number of FETs being used and their gate capacitance. Change the 1-uF C18 capacitor to ~2-uF, that should be enough to not see this big of a drop.

We explain this behavior in our Multiple FETs with the BQ76952, BQ76942 Battery Monitors application report.

Best Regards,

Luis Hernandez Salomon

Power management

Power management forum

BQ76952: Charge Pump Voltage is Decreasing in Charging & Dis-Charging