switching oscillator circuit

switching oscillator circuit

Switching oscillation circuit
    The switching oscillation circuit is mainly composed of the switching field effect transistor Qlol, the switching oscillation control integrated circuit Ul01 and related circuits.
The figure shows the switching oscillation circuit.
    When starting up, the 300 V DC voltage rectified and output by the 220 V AC voltage is added to the drain D of the switching transistor Ql01 through the primary winding ①~@ pin of
the switching transformer Tl01. The source S of the switching transistor is grounded through RⅢ, and the gate G is controlled by the ⑥ pin of the switching oscillation integrated circuit U1ba
.
    The 300 V DC voltage provides a starting voltage for the ① pin of U101, which starts the oscillator in U101 and provides an oscillation signal for the gate G of the switching transistor
Qlol . Then the switching transistor Q10l starts to oscillate, causing the switch transformer to activate the primary coil of T101. generates switching current. The induced current is generated in the secondary windings ③ and ④ of the switching
transformer. The output of ③ is rectified and filtered to form a positive feedback voltage and is added to
the ⑦ pin of Ul0], thereby maintaining the operation of the oscillation circuit and allowing the switching power supply to enter normal operation. state.