TPS65987D: Dead Battery Advertisement

Part Number: TPS65987D

I read the TPS65987D datasheet, and I am confused by Dead Battery Operation, the datasheet's explanation is not very clear.

1.What's the difference between the RD_DB and RD_CC, when the MOSFET turn-on both are connected to the ground.

2. What is the function of R_RPD, and how it works. I don not understand why need to connect this resistor to the gate of MOSFET.

over 4 years ago

0 Prajith Cheerakkoda over 4 years ago

TI__Expert 8680 points

Hello,

Dead-battery means there is no power available on the sink side and therefore cannot turn on MOSFET to present RD_CC. Whereas, R_RPD connected to gate of the MOSFET helps to turn on the MOSFET (path shown in the figure +v -> Rp -> R_RPD) and present RD_DB to the source. Hope my explanation help, please let me know if you need any clarification.

Thanks

Prajith

0 J over 4 years ago in reply to Prajith Cheerakkoda

Expert 1065 points

Hi Prajith,

Thanks for your answer,

I have one thing I am not understand

in the normal operation, the R_RPD still connects to the MOSFET gate, so the RD_DB always connects to the ground.

it has two paths to connect to the ground?

Jack

0 Prajith Cheerakkoda over 4 years ago in reply to J

TI__Expert 8680 points

RD_DB_EN signal can keep the FET disabled in normal operation.

Thanks

Prajith

0 J over 4 years ago in reply to Prajith Cheerakkoda

Expert 1065 points

Hi

So this circuit is used to detect the Dead Battery?

+1 Prajith Cheerakkoda over 4 years ago in reply to J

TI__Expert 8680 points

Hi Jack,

This circuit (blue path shown in the picture above) is to present dead-battery Rd during dead-battery.

Thanks
Prajith

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TPS65987D: Dead Battery Advertisement