BQ25700A: OTG voltage issue in no load condition

Wu JW

Part Number: BQ25700A

Hi, Team,

My customer found the output for the OTG voltage is always 0.5V lower than the setting voltage in no load condition. Such as we set the OTGVoltage Register as A00h for 7V OTG output, but the actually output is 6.5V in no load condition. Do you meet such issue? How about you suggestion? Thanks!

over 7 years ago

0 Wang5577 over 7 years ago

TI__Guru 56650 points

Wu,

What is the battery discharge current setting; system load and VBUS load?

0 hongshu mo over 7 years ago in reply to Wang5577

Prodigy 20 points

discharge current setting is default, system load and VBUS load is empty

0 Wang5577 over 7 years ago in reply to hongshu mo

TI__Guru 56650 points

Hongshu,

On my bench test, the OTG output is 7V with A00 OTG voltage setting.
Let us step by step to find out the root cause:
1. Check OTG current register setting: what value do you put?
2. Set OTG voltage register to 0x0000h to check OTG output offset voltage: what voltage do you get from the VBUS?

0 hongshu mo over 7 years ago in reply to Wang5577

Prodigy 20 points

1.OTGCurrent Register (SMBus address = 3Ch) ：1400H

2.When set OTG voltage register to 0x0000h ,and the VBUS voltage is 4V

0 Wang5577 over 7 years ago in reply to hongshu mo

TI__Guru 56650 points

Hongshu,

When set OTG voltage register to 0x0000h ,and the VBUS voltage should be 4.48V. Please read the IC top marking. If it has "BQ
25700A", please replace the IC and check it again. And then, if it is IC issue, please send it local FAE to start failure analysis.

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BQ25700A: OTG voltage issue in no load condition