Possible Reasons for Battery Overvoltage with FAN54015 Charger IC

Please let me know all possibilities for causing the fan54015 battery overvoltage.

Hi,

It best you check the datasheet of the fan54015. If you read its datasheet, it would indicate that the regulator has an overvoltage protection feature. But needless to say there are still many reason that may cause overvoltage to occur. When an unloaded line is charged, due to Ferranti Effect the receiving end voltage is increased considerably resulting in over voltage in the system. Also there is the possibility of stress in the insulation on the load side.

"fan54015("")":https://www.fairchildsemi.com/datasheets/FA/FAN54015.pdf

Hi there.
OVP is triggered when Vbus exceeds 6.29V.
OVP is released when Vbus drops below 6.19V.
Upon OVP detection, the prime pass transistor turns off shutting down the entire IC.
I think you can also force OVP condition by entering test mode [but only the designer knows the register settings].

Also, I am just wondering. The ferranti effect only occurs on long transmission lines. But I think the battery to PMIC connection is too short for it too be significant? Also, isn't the ferranti effect more prominent in AC lines?

That is all.

Regards,
Justin