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WEBENCH® Tools/BQ25120A: Need 3.3v out at SW to power up other components

vivek plawat1

Prodigy 240 points

Part Number: BQ25120A

Tool/software: WEBENCH® Design Tools

We are using this to power up other components in the device and trying to program bq25120a to get an output of 3.3V at SW. The components tick (√) marked were removed and we pulled down these pins. The issue is that we can not detect the bq25120a on I2C. Is something wrong in the schematic that we have done?

over 4 years ago

0 vivek plawat1 over 4 years ago

Prodigy 240 points

SCH_VPMED_M1.0-pages-1-3.pdf

0 Raheem over 4 years ago in reply to vivek plawat1

TI__Mastermind 21590 points

Hello,

What are the value of R23 and R25? The pull up resistors on SDA and SCL

If this is being done in battery only mode, you have to make sure /CD is high.

0 vivek plawat1 over 4 years ago in reply to Raheem

Prodigy 240 points

1. R23 and R25 are 0E, however, SDA1 and SCL1 have 10k (R21 and R20) resistors to 3.3v. Is it okay?

2. Understood that If this is done in battery mode CD need to be high, After detecting by I2C and programmed, shall I keep High or open or low?

3. Let me know how to detect bq25120a by I2C if it is in sys 5v and not on battery?

regards

Vivek

0 Raheem over 4 years ago in reply to vivek plawat1

TI__Mastermind 21590 points

1) That's fine.

2) You can set /CD low after I2C transaction to enter Hi-z mode and reduce battery Iq.

3) If VIN is present, I2C is active. You can use the PG pin to determine when VIN is present.