BQ25756: OUTPUT IS ERR

zhimin wang

Part Number: BQ25756
Other Parts Discussed in Thread: BQSTUDIO, EV2400,

Tool/software:

Now I am doing a project, the standby battery charges the main battery (42V/5A), the standby battery is 25~42V, configured in reverse mode, but the output is only 5V all the time, and the overvoltage will be displayed. When EV2400 is used to communicate with bqstudio, the DEVICE ERR is often displayed, the schematic diagram is as follows, please help to analyze the reason, thank you

BQ25756_BUCK_BOOST.pdf

10 months ago

0 Ethan Galloway 10 months ago

TI__Mastermind 31225 points

Hello Zhimin,

Thanks for working with us on this. I think the EV2400 is having trouble communicating with the BQ25756 here. I have a few questions to help troubleshoot this:

Was the EV2400 plugged into the computer before starting BQStudio?
Does the BQ25756 have at least 3V on either VAC or VBAT?
Can you see SDA and SCL pulling down to communicate?

By the way, the capacitance will need to be balanced across the sense resistors. Please see this FAQ on it. Here's our general FAQ for the BQ25756.

Best Regards,
Ethan Galloway

+1 zhimin wang 10 months ago in reply to Ethan Galloway

Prodigy 10 points

the schematic is ok?

Was the EV2400 plugged into the computer before starting BQStudio?

---yes

Does the BQ25756 have at least 3V on either VAC or VBAT?

---VBAT input is 36V

Can you see SDA and SCL pulling down to communicate?

---

0 zhimin wang 10 months ago in reply to zhimin wang

Prodigy 10 points

0 Ethan Galloway 10 months ago in reply to zhimin wang

TI__Mastermind 31225 points

Hello Zhimin,

Yes, your schematic looks good.

I see you marked the question as resolved. Let me know if you need any more help with this question.

Best Regards,
Ethan Galloway

Power management

Power management forum

BQ25756: OUTPUT IS ERR