JPS63191884U

JPS63191884U -

Info

Publication number: JPS63191884U
Application number: JP8254187U
Authority: JP
Priority date: 1987-05-29
Filing date: 1987-05-29
Publication date: 1988-12-09

Description

[Brief explanation of the drawing]

第１図は本考案によるスイツチング電源の過電
流保護回路の第１実施例を示す電気回路図、第２
図は本考案の第２実施例の電気回路図、第３図は
本考案の第３実施例の電気回路図、第４図は各部
の特性図、第５図はＩＣ内の各部の特性図、第６
図は従来の電気回路図である。１……主トランス、２……１次巻線、３……主
開閉素子、４……直流電源、５……２次巻線、１
２……検出増幅回路、１４……電源用ＩＣ、１５
……変流器、１９……コンデンサ、２０……抵抗
、２１……時比率制御増幅器、２４……全波整流
器、、２５……ツエナーダイオード。 Fig. 1 is an electric circuit diagram showing a first embodiment of the overcurrent protection circuit for a switching power supply according to the present invention;
The figure is an electric circuit diagram of the second embodiment of the present invention, Figure 3 is an electric circuit diagram of the third embodiment of the present invention, Figure 4 is a characteristic diagram of each part, and Figure 5 is a characteristic diagram of each part in the IC. , 6th
The figure is a conventional electrical circuit diagram. 1... Main transformer, 2... Primary winding, 3... Main switching element, 4... DC power supply, 5... Secondary winding, 1
2...Detection amplifier circuit, 14...Power supply IC, 15
... Current transformer, 19 ... Capacitor, 20 ... Resistor, 21 ... Time ratio control amplifier, 24 ... Full wave rectifier, 25 ... Zener diode.

Claims

[Scope of Claim for Utility Model Registration] (1) Chopping a DC power supply using a chopper circuit mainly consisting of a main switching element, smoothing it to obtain a DC output, and detecting and amplifying this DC output for duty ratio control. In a switching power supply circuit in which input is input to a comparison circuit of an IC and the duty ratio of opening/closing of the main switching element is controlled by the output of this IC, a primary winding of a reactor is inserted into the chopper circuit,
A parallel circuit of a capacitor and a resistor is connected to the secondary winding of this reactor via a full-wave rectifier, and the output side of this parallel circuit is connected to the duty ratio control terminal of the IC via a series circuit of a resistor and a Zener diode. An overcurrent protection circuit for a switching power supply, characterized in that the circuit is coupled to a switching power supply. (2) A chopper circuit is a practical circuit in which a main transformer and one or more main switching elements are connected in series, and AC voltage is output to the secondary side of the main transformer by switching the main switching element. An overcurrent protection circuit for a switching power supply as claimed in claim 1. (3) The chopper circuit includes a main switching element inserted into a DC power supply line, and a pulse voltage is output by switching the main switching element. Current protection circuit. (4) The overcurrent protection circuit for a switching power supply according to claim 1, wherein the full-wave rectifier is bridge-connected.