LED rechargeable flashlight circuit principle

It can be seen that since the design voltage is 220V, when the voltage is too high, the voltage after step-down and rectification must rise, which will not only cause overvoltage charging of the battery, but also cause the battery to be scrapped prematurely. If the light is turned on during charging, the It is possible to burn out the LED, and because the battery voltage may reach 4.9V after charging, the current-limiting resistor is still necessary, which can prolong the service life of the LED. (I have found inferior products without current-limiting resistors).