There may be several reasons:
1. The LED lamp bead does not match the LED drive power supply.
2. The power transformer is not properly installed, the parameters do not meet, and the windings are not installed or too many, resulting in magnetic saturation or insufficient inductance.
3. The feedback circuit is faulty.
4. The load current is too large or the load voltage is too small, which is lower than the minimum output voltage of the power supply, causing automatic protection.
5. The design of the voltage sampling circuit is unreasonable, and the power supply voltage is too low, lower than the normal working voltage, causing the power supply to fail to start.