US Patent 10429016 LED light string with stable current

An LED light string has a plug, a socket, a lighting string connected between the plug and the socket, and a control circuit provided in either the plug or the socket. The control circuit uses at least one current controller to control a driving current flowing through the lighting string stably. When a temperature of the lighting string exceeds a threshold, the current controller activates its over-temperature protection function to lower the driving current. When short-circuit occurs on the lighting string, the current controller activates its short-circuit protection function to lower the driving current.