Hi
The customer design the Bluetooth earphone, and Doing a cycle test:
insert the USB 5V and charge for 10 seconds plug out the USB 5V and wait for 10 seconds insert the USB 5V and charge for 10 seconds......
It is found that sometimes the current is unstable, and it fluctuates unstable at 260mA-60mA-180mA-230mA.
According to Figure 1, measure the battery voltage 3.87V, the voltage of the battery line passing through a 580mm wire to the right = 3.95V.
As long as the battery voltage is close to 3.87V, unplug the USB 5V and then insert the USB 5V, the current will be unstable, if it is lower than 3.80V or higher than 4.05V, it will not appear. Or charging from 3.30V to 4.18V will not appear.
Figure 2. If the battery is directly connected to out pin without passing through Fuse and 580mm wire, the charging current will not be unstable;
1. The voltage difference between the Fuse and the 580mm length of the battery leads to unstable current. Any suggestions?
2. Why is the charging current unstable after the battery passes through the Fuse and the 580mm length wire?
Waiting for your reply.
Thanks
Star
