| 摘要 |
PROBLEM TO BE SOLVED: To prevent the switching element of a ringing choke converter from being damaged by rapidly stopping its oscillation when AC input is broken. SOLUTION: In the ringing choke converter, a full-wave rectification circuit, a first smoothing capacitor, a switching element (FET), and a control circuit are provided at the primary side of a converter transformer, the base of a first NPN transistor (NPN transistor, collector, base, and emitter are abbreviated as Q, C, B, and E below) is connected to the control circuit, the C of the Q and that of the second Q are connected to the gate of the switching element (FET), at the same time the E of the first Q and that of the second Q are connected, and then the B of the second Q and the C of the third Q are connected. In the ringing choke converter the E of the third Q and the C of the fourth Q are connected, the input side of the full-wave rectification circuit and the B of the fourth Q are connected by an input voltage detection circuit, and a smoothing circuit consisting of the second smoothing capacitor and the first resistor is composed between the B and E of the fourth Q.
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