CN102412736A

CN102412736A - Electronic transformer

Info

Publication number: CN102412736A
Application number: CN2011104066521A
Authority: CN
Inventors: 王寅寅; 何林
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-12-08
Filing date: 2011-12-08
Publication date: 2012-04-11

Abstract

The invention relates to an electronic transformer, which consists of a 220V alternating current power supply, a full bridge rectifying circuit, a start-up trigger circuit, a high-frequency oscillation circuit and a low-voltage output port, wherein the full bridge rectifying circuit is formed by connecting 4 silicon rectifier diodes D1-D4. The electronic transformer disclosed by the invention has the advantages similar to those of a switch stabilized voltage supply. For example, as the frequency of alternating current output by the electronic transformer is about 150-200KHz, filtering of pulsating direct current after rectification is relatively easy, and the capacity of a filtering capacitor in the circuit does not need to be too large, which decreases the weight of the electronic transformer and reduces the manufacturing cost in one respect; with the electronic transformer, generating one or more groups of different output voltages is easy; as the circuit of the electronic transformer has an overflow protection function, once overload or short circuit occurs to the load of the output port, the circuit can instantly stop oscillating, thereby stopping outputting high-frequency alternating voltage; and good effect of safe isolation between the direct voltage output port and the 220V alternating current power supply is achieved.

Description

Electronic transformer

Technical field

The invention belongs to electronic technology and power technique fields, relate to a kind of electronic transformer.

Background technology

The operation principle and the switching power supply of electronic transformer are closely similar, and in fact it is exactly a kind of AC inverter.At first become Rectified alternating current to alternating current; Form a high-frequency generator with electronic component then direct current is become high-frequency alternating current; Export needed high-frequency alternating current through electronic transformer then, then carry out secondary, rectifying and wave-filtering obtains low-voltage DC.Be characterized in that electronic transformer is again unlike using a lot of electronic components in the such circuit of switching power supply.It is on the basis of high-frequency electronic ballast circuit theory, a kind of new type electronic transformers of development, and it has, and volume is little, in light weight, power is big, power supply conversion efficiency is higher, the advantage of stable work in work.Having overcome traditional silicon steel sheet making transformer has big, heavy, the defectives such as the consumption copper material is many, price height of volume, so the high-frequency electronic transformer can be widely used in the various electrical equipment.

Below specify this electronic transformer related correlation technique content in manufacturing process.

Summary of the invention

Goal of the invention and beneficial effect: electronic transformer of the present invention has the advantage of similar switching power supply; As: because of the about 150～200KHz of frequency of electronic transformer output AC electricity; Thereby the filtering of Rectified alternating current is relatively easy after the rectification; The capacity of the filter capacitor in the circuit does not need too big, and this is an aspect that alleviates electronic transformer weight, reduces cost of manufacture; Electronic transformer is made one or more groups different output voltage easily; The circuit of electronic transformer has overcurrent protection, in case overload or short circuit take place in the load of output, circuit is failure of oscillation and stop the output of high-frequency ac piezoelectric voltage at once; Dc voltage output end and 220V AC power have good safe isolation effect; Be suitable for making the various DC power supplys that electric power is no more than 50W.

The circuit working principle: the operation principle and the Switching Power Supply of electronic transformer are closely similar; The about 200KHz of the frequency of electronic transformer output AC voltage; Silicon rectifier diode D1～D4 constitutes bridge rectifier and becomes Rectified alternating current to the 220V AC power; By higher-order of oscillation transformer, NPN transistor BG1, BG2 form high-frequency oscillating circuits, and Rectified alternating current is become high-frequency alternating current; Simultaneously high-voltage pulse is carried out step-down, obtain 12V high-frequency ac output voltage by ferrite higher-order of oscillation transformer.Resistance R 1 in the circuit, capacitor C 1 and bidirectional trigger diode D5 constitute start triggering circuit.

Shortcoming of the present invention is: the electronic transformer periphery can produce certain electromagnetic and disturb, but can the electromagnetic interference that oscillating circuit produces be absorbed through increasing absorption circuit.

Technical characterictic: electronic transformer, to form by 220V AC power, full bridge rectifier, start triggering circuit, high-frequency oscillating circuits and low-voltage output mouth, its characteristic comprises:

Full bridge rectifier: be connected into full bridge rectifier by 4 silicon rectifier diode D1～D4; The live wire end L of 220V AC power and zero line side N are connected on the alternating current input that 4 silicon rectifier diode D1～D4 constitutes full bridge rectifier respectively; The anodal VCC of the anodal connection circuit of full bridge rectifier dc output end, the negative pole connection circuit ground GND of full bridge rectifier output;

High-frequency oscillating circuits: the anodal VCC of the collector electrode connection circuit of NPN transistor BG1; The base stage of NPN transistor BG1 connects the end of higher-order of oscillation Transformer Winding L1; The emitter of another termination NPN transistor BG1 of higher-order of oscillation Transformer Winding L1 and the collector electrode of NPN transistor BG2; The base stage of NPN transistor BG2 connects the end of higher-order of oscillation Transformer Winding L3, and the emitter of NPN transistor BG2 meets the other end and the circuit ground GND of higher-order of oscillation Transformer Winding L3;

Start triggering circuit: the base stage of the termination NPN transistor BG2 of bidirectional trigger diode D5; The end of the other end connecting resistance R1 of bidirectional trigger diode D5 and an end of capacitor C 1; The anodal VCC of the other end connection circuit of resistance R 1, the other end connection circuit ground GND of capacitor C 1;

Low-voltage output mouth: the end of a termination higher-order of oscillation Transformer Winding L2 of low-voltage output mouth and the emitter of NPN transistor BG1 and the collector electrode of NPN transistor BG2, the other end of another termination low-voltage output mouth of higher-order of oscillation Transformer Winding L2.

Description of drawings

Accompanying drawing 1 is the circuit working schematic diagram of electronic transformer; Higher-order of oscillation transformer in the accompanying drawing 1 has 3 windings, that is: winding L 1, winding L 2, winding L 3.

Embodiment

Implement according to the specification requirement of the components and parts of the circuit working schematic diagram of electronic transformer shown in the accompanying drawing 1 and description of drawings and the following stated and the annexation between the components and parts, can realize the present invention.

The selection of components and parts and technical parameter

D1～D4 selects 4 1N4007 type silicon rectifier diodes for use;

D5 is a bidirectional trigger diode, and model is selected the DB3 type for use, or selects the VR60 type for use, and withstand voltage requires at 29～34V;

BG1, BG2 are NPN transistor, and model is selected 2CS13005 for use, and current amplification factor β value requires 15～20, also can select high-power high back-pressure silicon transistors such as 2SC3093 for use, require BVceo >=350V;

Resistance is selected the 1/4W metalfilmresistor for use, and the resistance of resistance R 1 is that 330K Ω, power are 1W;

Capacitor C 1 is selected the polypropylene/polyester electric capacity of the dacron for use, and the capacity of capacitor C 1 is 0.01 μ F/250V.

Circuit production main points and debugging

The making of higher-order of oscillation transformer: ferrite bead is of a size of external diameter 12mm * internal diameter 7mm * high 7mm, and with the coiling of diameter 0.33mm high strength enamelled wire, winding L 1 and L3 are all around 4 circles, and winding L 2 is around 2 circles;

The electronic transformer circuit is so long as the electronic devices and components performance of selecting for use is intact, and the annexation of accompanying drawing and components and parts is welded to specifications, and after physical connection line and welding quality process scrutiny were errorless, circuit need not debugged basically and get final product operate as normal;

Ifs circuit can not normally vibrate, or low-voltage output mouth undertension 12V, and then further check circuit has error-free weldering, leaks weldering or rosin joint; And then whether the performance of checking NPN transistor BG1, BG2 respectively is good, and whether the phase place of higher-order of oscillation Transformer Winding L1, L3 is correct;

After entire circuit debugging is normal, can pack in the capsule made from metal material, help the shielding of electronic transformer circuit like this, but will notice that circuit and shell must insulate well.Change the number of turn of higher-order of oscillation Transformer Winding L2, then can change the value of high-frequency output voltage;

The important technological parameters of electronic transformer: AC power input voltage 220V, low-voltage output mouth output high-frequency ac voltage is 12V, power supply conversion efficiency is about 70%, the about 40～50W of peak power output.

Claims

1. an electronic transformer is made up of 220V AC power, full bridge rectifier, start triggering circuit, high-frequency oscillating circuits and low-voltage output mouth, and its characteristic comprises:

Full bridge rectifier is connected into full bridge rectifier by 4 silicon rectifier diode D1～D4; The live wire end L of 220V AC power and zero line side N are connected on the alternating current input that 4 silicon rectifier diode D1～D4 constitutes full bridge rectifier respectively; The anodal VCC of the anodal connection circuit of full bridge rectifier dc output end, the negative pole connection circuit ground GND of full bridge rectifier output;

The anodal VCC of the collector electrode connection circuit of NPN transistor BG1 in the high-frequency oscillating circuits; The base stage of NPN transistor BG1 connects the end of higher-order of oscillation Transformer Winding L1; The emitter of another termination NPN transistor BG1 of higher-order of oscillation Transformer Winding L1 and the collector electrode of NPN transistor BG2; The base stage of NPN transistor BG2 connects the end of higher-order of oscillation Transformer Winding L3, and the emitter of NPN transistor BG2 meets the other end and the circuit ground GND of higher-order of oscillation Transformer Winding L3;

The base stage of the termination NPN transistor BG2 of bidirectional trigger diode D5 in the start triggering circuit; The end of the other end connecting resistance R1 of bidirectional trigger diode D5 and an end of capacitor C 1; The anodal VCC of the other end connection circuit of resistance R 1, the other end connection circuit ground GND of capacitor C 1;

The end of one termination higher-order of oscillation Transformer Winding L2 of the low-voltage output mouth in the low-voltage output mouth and the emitter of NPN transistor BG1 and the collector electrode of NPN transistor BG2, the other end of another termination low-voltage output mouth of higher-order of oscillation Transformer Winding L2.