Three-level protection method aiming at different fault characteristics of LED (Light Emitting Diode) power supply

The invention discloses a three-level protection method aiming at different fault characteristics of an LED (Light Emitting Diode) power supply. The three-level protection method comprises the following steps: detecting an operation state of the power supply, shutting down the system through hardware when the state of the power supply changes suddenly, performing stress adjusting secondary protection when a fault changing gradually occurs, namely enabling the power of the power supply to reduce through the reducing speed of a pulse width in a unit time, starting a third-level protection soft-off if the power supply fault tendency is not eliminated after adjusting the stress, then reducing a PWM (Pulse-Width Modulation)pulse width till the width of the PWM pulse is reduced to be 0, and turning off the power supply and shutting down when the output power of the power supply is 0. Through the three-level protection method, three-level protection is mainly applied to the power supply; the emergency faults and the faults gradually changing are processed by using different methods; the faults are avoided by adjusting the stress; the three-level protection method is capable of improving the reliability of the power supply, reducing the fault rate and eliminating or reducing bottleneck effect caused by the power supply in an electronic system.