In the voltage feedback sampling ci

In the voltage feedback sampling circuit in FIG. 4.5, a capacitor C16 is connected to both ends of the voltage regulator tube TL431. It has the function of delayed soft start, which can reduce the stress on the components. The length of the delay time is related to the power output of the switching power supply. Generally, the delay time of the high-power power supply is 30 ~ 45ms, and the delay time of the low-power power supply is 10 ~ 30ms. The delay time of the power supply mainly depends on the capacity of the starting capacitor and also on the input impedance of the power supply circuit. The starting time should be adjusted, and the delay time should not be too long, otherwise the control sensitivity will be affected [11].