JPH01116588U

JPH01116588U -

Info

Publication number: JPH01116588U
Application number: JP1150588U
Authority: JP
Priority date: 1988-01-29
Filing date: 1988-01-29
Publication date: 1989-08-07

Description

[Brief explanation of the drawing]

第１図は、本考案の実施例における回路構成図
を示す。第２図は、本考案の実施例における動作
原理を説明する図である。第３図は、従来例の回
路構成図を示す。１１，３１……入力直流電源。１２，３２……
トランス。１３，３３……第１のトランジスタ。
１４，１１２，１１５，３５，３７，３１４，３
１６……ダイオード。１６，３９……出力直流電
圧。１１０，３１３……第２のトランジスタ。１
５，１１４，３８，３１５，３１８……コンデン
サ。１７，３１０……誤差増幅器。１８，３１１
……フオトダイオード。１９，３２０……フオト
トランジスタ。３４……起動抵抗。３６，１１１
，３１２，３１７……抵抗。Ｎ１，Ｎ２，Ｎ３，
Ｎ４……巻線。２１，２２，２３，２４，２５，
２６……電圧波形。１１３……入力側接地端子。 FIG. 1 shows a circuit configuration diagram in an embodiment of the present invention. FIG. 2 is a diagram illustrating the operating principle in the embodiment of the present invention. FIG. 3 shows a circuit configuration diagram of a conventional example. 11, 31...Input DC power supply. 12, 32...
Trance. 13, 33...first transistor.
14,112,115,35,37,314,3
16...Diode. 16, 39...Output DC voltage. 110, 313...Second transistor. 1
5,114,38,315,318... Capacitor. 17,310...Error amplifier. 18,311
...Photodiode. 19,320...Phototransistor. 34...Starting resistance. 36,111
, 312, 317...Resistance. N1, N2, N3,
N4... Winding wire. 21, 22, 23, 24, 25,
26...Voltage waveform. 113... Input side grounding terminal.

Claims

[Scope of utility model registration request]

The primary winding of the transformer and the first transistor are connected in series to the input DC power supply, and the base power supply for turning the first transistor on and off is connected to the positive terminal of the input DC power supply and the first transistor at startup. input through a starting resistor between the base of the transistor and
After startup, the voltage induced in the base drive winding on the primary side of the transformer is used to drive the base of the first transistor via the negative pole of the input DC power supply and the base resistor and diode, and the first transistor is used as the base power supply. The transistor is turned on and off to excite the primary winding, and the second
A pulse voltage is obtained in the next winding, rectified and smoothed to output a DC voltage, and an error signal between the output voltage and the reference voltage is insulated between the primary and secondary of the circuit by an error amplifier, and the first transistor It is fed back to the primary side by the photocoupler as a base drive signal of the second transistor for controlling the base current of the first transistor.
This is a self-excited switching power supply that controls the on-time of the transistor to obtain stable DC output.
Moreover, the connection point between the primary winding of the transformer and the first transistor is connected to the positive electrode side of a diode via a resistor, and the negative electrode side of the diode is connected in series to the collector side of the phototransistor. A self-excited switching power supply characterized by having a circuit configuration in which a capacitor is connected between the negative electrode and the negative electrode of an input DC power source to obtain a base side power source for a second transistor.