The basic principle of parallel switching power supply
After the 220V alternating current is rectified and filtered by C1, a 300V direct current voltage is obtained on C1, and the voltage is sent to the collector of the switch tube VT.
When the high-level pulse signal is sent to the base of the VT, the VT is saturated and turned on, and the 300V voltage generates current to the ground through VT and L1. When the current passes through L1, L1 will generate positive and negative electromotive force to block the current, and at the same time Energy is stored in L1; when the low-level pulse signal is sent to the base of VT, VT is turned off, no current flows through LI, and L1 immediately generates an upper negative and lower positive electromotive force, which makes the freewheeling diode VD1 conduct. And the capacitor C2 is charged, and the charging path is: the lower positive of LI → C2 → VD1 → the upper negative of L1, and the upper negative and lower positive voltage U0 is charged on C2, and this voltage is supplied to the load RL.
