JPH0363082U

JPH0363082U -

Info

Publication number: JPH0363082U
Application number: JP12491789U
Authority: JP
Priority date: 1989-10-24
Filing date: 1989-10-24
Publication date: 1991-06-20

Description

[Brief explanation of drawings]

第１図は本考案の一実施例を示す電源回路の要
部回路図、第２図は本考案の他の実施例を示す電
源回路の要部回路図、第３図は従来例の電源回路
の要部回路図である。１……入力端子、２……変圧器、３，１２，２
４……トランジスタ、４，５，１１，２２，２３
……抵抗器、６，７，３０……巻線、９，３１…
…ダイオード、１０，３２……コンデンサ、１３
，２１，３３……ツエナーダイオード、１４，３
４……出力端子。 Fig. 1 is a circuit diagram of a main part of a power supply circuit showing one embodiment of the present invention, Fig. 2 is a circuit diagram of a main part of a power supply circuit showing another embodiment of the invention, and Fig. 3 is a power supply circuit of a conventional example. FIG. 1...Input terminal, 2...Transformer, 3, 12, 2
4...Transistor, 4, 5, 11, 22, 23
...Resistor, 6,7,30...Winding, 9,31...
...Diode, 10, 32...Capacitor, 13
, 21, 33... Zener diode, 14, 3
4...Output terminal.

Claims

[Claims for Utility Model Registration] (1) Take the output from the secondary winding of a transformer, rectify the output with a diode and a capacitor, input it to a regulator circuit, and branch the input circuit of the circuit so that one side is connected to the other. The cathode of a Zener diode is connected to the collector of the first transistor, the other branched end is connected to the base of the first transistor via a resistor, and the base and anode side of the first transistor are grounded. and a load connected to the emitter of the first transistor by causing a Zener current to flow from the input circuit to the Zener diode through the resistor to maintain the base voltage of the first transistor constant. In a DC power supply circuit having a regulator circuit that supplies a constant voltage to the transformer, a means for detecting a voltage rise in a secondary winding of the transformer is provided, and a base voltage control means is further provided at the base of the first transistor. The output detected by the detection means is applied to the control means to change the base voltage of the first transistor, so that the output generated at the secondary winding of the transformer increases and exceeds the regulation range of the regulator circuit. A power supply circuit characterized in that, at times, the first transistor is turned off to interrupt a power supply circuit that supplies a load. (2) The detection means includes a circuit in which the cathode of a Zener diode is connected to the input circuit of the regulator circuit, and the anode of the Zener diode is connected to ground via a resistor, and the control means is connected to the Zener diode. Connect one end of the resistor to the connection point of the resistor, and connect the other end of the resistor to the second
2. The power supply circuit according to claim 1, further comprising a circuit in which the collector of the second transistor is connected to the base of the first transistor, and the collector of the second transistor is connected to the base of the first transistor. (3) The detection means includes a voltage detection winding attached to a transformer, a diode, and a capacitor, and the control means includes a Zener diode, and the output obtained from the voltage detection winding is connected to the diode. 2. The power supply circuit according to claim 1, comprising a circuit in which the DC voltage is rectified by a capacitor, and in addition to the anode of the Zener diode, the cathode of the Zener diode is connected to the base of the first transistor. .