This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ25120AEVM: BQ25120AEVM does not gives VLDO output

Part Number: BQ25120AEVM
Other Parts Discussed in Thread: BQSTUDIO, BQ25120A, EV2400

I am trying to test the BQ25120AEVM for a potential wearable with wireless charging source. Before testing the wireless sub block, I wanted to test this for stable 1.8V output on VLDO net. I connected the micro USB power cable, and saw PG LED turn on , but there is no voltage on VLDO. How do I set it to 1.8V?

  • Hi Devang, 

    On the BQ25120AEVM you want to make sure the jumper J5 is connected. This will connect the PMID output o the VINLS input. The VINLS is the supply of the LDO. Is the J5 connected? 

    Best regards, 

    Arelis G. Guerrero 

  • Hi Arelis,

    My connection is exactly like you mentioned (J5.), what else can I look at? 

    ~Devang 

  • Hi Devang, 

    Afterwards, you need to set the LDO Voltage to 1.8V and then enable the LDO output on the Load Switch and LDO Control Register (0x07). On the BQ25120A the default configuration is as a load switch and disabled, so you will need to change it via I2C. For your setup (1.8V/LDO), the value on the register needs to be 0xA8. You can use the EV2400 and the BQStudio software to communicate with the charger and change the registers. Please refer to the BQ25120AEVM User Guide for more details. 

    BQ25120A EVM User Guide: https://www.ti.com/lit/pdf/sluubq5

    Also, you can refer to the FAQ compilation app note, which has some good information about how to get started with the BQ25120A. 

    BQ2512x FAQs: https://www.ti.com/lit/pdf/sluaah8

    Best regards, 

    Arelis G. Guerrero