Hi team,
My customer met an issue shown as below.
The pos machine shows charging icon without adapter plug in, the voltage on the Vbus is measured at 6.4V(register also shows VBUS: 6.4V), VBAT: 7.6V, the problem is replicated serial log in the attachment. And when this issue occurs, the IC will heat up.
This issue recurs four times on the same IC, we changed to another IC on the same system, it looks normal.
1.For the first time the charge occurs normally, the issue is occasionally observed after unplugging。
2.For the second time, after the machine has made a high and low temperature testing, the machine appears icon does not disappear
3.For the third time, charge for a long time. After the battery has dropped, I unplug the charger and see the charging icon is still present.
4.For the fourth time, power on/off charging test, unplug the battery charger after turning on the battery to find the icon is present
I find the register REG0B shows "no charging", so I am checking the logic of charging icon appearance in customer's system.
But what confused me most is that why VBUS shows 6.4V when no adapter plug in? Register also shows 6.4V.
The schematic is shown below and the voltage measurement points are indicated by an arrow with a voltage of approximately 6.4 V.
Do you have any comments on this issue?
Thanks!
Best regards
Lillian Liu
