5V charge and discharge module IP5407

Most charging and discharging modules will automatically sleep under low load conditions. IP5407 supports a fixed and always-on output of 5V. In the sleep state, the battery indicator light will be extinguished, and 5V will still be output normally.
Test situation description: The official document mentions that if the solution does not require NTC, the KEY pin needs to be connected to a 51K resistor to GND. Otherwise, charging and discharging abnormalities may occur.
My personal understanding is that the KEY and the 51K resistor need to be connected in series. After the actual test, it was found that 5v was output normally after the button was pressed, but 5v was not output after the button was released, so the key and 51K resistor were modified in parallel. Power on test, no problem for now.
The drawing has been modified to the parallel connection state of KEY and 51k. The actual KEY is not welded and does not affect its use.