JPH01101176U

JPH01101176U -

Info

Publication number: JPH01101176U
Application number: JP12625987U
Authority: JP
Priority date: 1987-08-19
Filing date: 1987-08-19
Publication date: 1989-07-07

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
圧保護回路の一実施例をスイツチング電源ととも
に示す回路図、第２図に従来技術による過電圧保
護回路を組み込んだ第１図と同じスイツチング電
源の回路図である。図において、１……交流電源、２，５……整流回路、３，６
……平滑用キヤパシタ、４……補助変圧器、１０
……スイツチング回路、１１……スイツチングト
ランジスタ、１２……信号変成器、１３，１４…
…抵抗、１５……キヤパシタ、２０……変圧器、
３０，４０……出力回路、３１，４１……整流用
ダイオード、３２，４２……平滑用リアクトル、
３３，４３……出力電圧安定用キヤパシタ、３４
，４４……フリーホイーリング用ダイオード、５
０……制御回路、６０……給電源ないしは三端子
レギユレータ、７０……過電圧検出回路、７１〜
７３……ツエナダイオード、７４，７５……抵抗
、８０……給電停止回路、８１……サイリスタ、
９１，９２……ツエナダイオード、９３……ホト
カプラ、９３ａ……発光ダイオード、９３ｂ……
ホトサイリスタ、９４，９５，９６……抵抗、Ｓ
Ｓ……スイツチング回路に対する開閉指令、Ｖａ
……給電源の入力電圧、Ｖｉ……スイツチング電
源の入力電圧、Ｖｏ１，Ｖｏ２……スイツチング
電源の出力電圧、である。 Fig. 1 is a circuit diagram showing an embodiment of the overvoltage protection circuit for a switching power supply according to the present invention together with a switching power supply, and Fig. 2 is a circuit diagram of the same switching power supply as shown in Fig. 1 incorporating an overvoltage protection circuit according to the prior art. . In the figure, 1... AC power supply, 2, 5... Rectifier circuit, 3, 6
... Smoothing capacitor, 4 ... Auxiliary transformer, 10
... Switching circuit, 11 ... Switching transistor, 12 ... Signal transformer, 13, 14 ...
...Resistor, 15...Capacitor, 20...Transformer,
30, 40... Output circuit, 31, 41... Rectifier diode, 32, 42... Smoothing reactor,
33, 43... Capacitor for output voltage stabilization, 34
, 44...Freewheeling diode, 5
0...Control circuit, 60...Power supply or three-terminal regulator, 70...Overvoltage detection circuit, 71~
73...Zena diode, 74, 75...Resistor, 80...Power supply stop circuit, 81...Thyristor,
91, 92... Zena diode, 93... Photocoupler, 93a... Light emitting diode, 93b...
Photothyristor, 94, 95, 96...resistance, S
S... Opening/closing command for the switching circuit, Va
. . . input voltage of the power supply, Vi . . . input voltage of the switching power supply, Vo1, Vo2 . . . output voltage of the switching power supply.

補正平１．２．８図面の簡単な説明を次のように補正する。明細書第１６頁第２行目に「第２図に」とある
のを「第２図は」と補正する。Amendment 1.2.8 The brief description of the drawing is amended as follows. In the second line of page 16 of the specification, the phrase "in Figure 2" is amended to read "in Figure 2."

Claims

[Claims for Utility Model Registration] (1) An input circuit section including a switching circuit that receives an input voltage and intermittents a current taken from the input voltage and an output circuit section that generates an output voltage to be supplied to a load are at a potential of A circuit that protects a switching power supply from overvoltage, in which a control circuit for controlling the opening and closing of a switching circuit and a power supply for the control circuit are electrically contained in an output circuit section, and that are separated from each other from overvoltage. The output circuit section is equipped with an overvoltage detection circuit that detects overvoltage applied to the circuit section and a power supply stop circuit that can stop the power supply from the power supply to the control circuit. An overvoltage protection circuit for a switching power supply, characterized in that the switching circuit in the input circuit section is turned off by stopping the power supply from the power supply to the control circuit, and the operation of the switching power supply is forcibly stopped. (2) In the protection circuit described in Claim 1 of the Utility Model Registration Claim, the overvoltage detection circuit is configured as a series circuit of a Zener diode and a common resistor connected to each point in the output circuit section where overvoltage is to be detected. An overvoltage protection circuit for a switching power supply, characterized in that the voltage applied to a common resistor during operation of a Zener diode is emitted as an overvoltage detection signal. (3) In the protection circuit set forth in claim 1 of the utility model registration claim, the power supply stop circuit is a thyristor connected between a pair of power supply lines for a control circuit of a power supply and turned on by a detection signal from an overvoltage detection circuit. An overvoltage protection circuit for a switching power supply, comprising: (4) An overvoltage protection circuit for a switching power supply, characterized in that the power supply is a three-terminal regulator capable of short-circuiting its output voltage in the protection circuit according to claim 3 of the utility model registration claim.