BQ4050: Inquiry about the pull-up details of the pins on BQ4050-DISP.

jinbin lin

Part Number: BQ4050

Tool/software:

Technical Support Inquiry: DISP Pin Pull-Up Issue with Key-Press Circuit

Problem Description

We are encountering an issue where the DISP pin voltage fails to drop to a valid logic-low level when a 1kΩ pull-down resistor is connected between the key-press switch and ground. We seek clarification on the following:

How is the DISP pin pulled up? The datasheet mentions an 8kΩ resistor between DISP and PBI—what is the exact connection topology?
We measured that the voltage value of the DISP pin is approximately 4.5V. Why is the measured DISP voltage 4.5V? Which internal parameter defines this value? What are the details of the internal pull-up mechanism?
Can we replace the 1kΩ resistor with a 0Ω resistor? What are the specific constraints or risks?

2 months ago

0 Alan Frias 2 months ago

TI__Mastermind 31020 points

Hello,

This question has been assigned within the team and will be followed up when possible. In the meantime please attach associated .gg/.log file.

Thank you,
Alan

0 jinbin lin 2 months ago in reply to Alan Frias

Prodigy 10 points

ok, Look forward to your reply

0 Miguel Castro Gonzalez 2 months ago

TI__Intellectual 2792 points

Hello Jinbin,

PBI should have voltage equal to your BAT. Charges the capacitor. So the PBI and the DISP will need the resistor.
This might a be a floating voltage, generally, we ask the customer to ground it if there are not using it.
Usually, if not being used, the pin is shorted to ground, so it should be fine to use 0Ω.

-Miguel

Power management

Power management forum

BQ4050: Inquiry about the pull-up details of the pins on BQ4050-DISP.

Technical Support Inquiry: DISP Pin Pull-Up Issue with Key-Press Circuit

Problem Description