CN1036487A

CN1036487A - Stepless ac-dc converter

Info

Publication number: CN1036487A
Application number: CN 88101968
Authority: CN
Inventors: 李振江
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-04-08
Filing date: 1988-04-08
Publication date: 1989-10-18

Abstract

The present invention is the stepless AC-DC converter that belongs to a kind of transless power frequency switching regulator, and it is made up of rectification circuit, synchronous high-voltage switch gear, control circuit, storage capacitor, filter and linear voltage regulator.Be characterized in that without Industrial Frequency Transformer by the direct full-wave rectification of rectification circuit, the break-make of controlling synchronous high-voltage switch gear by control circuit comes storage capacitor is discharged and recharged again, reaches predetermined voltage, and then by filtering and voltage stabilizing output.The present invention can be as the power supply in color television set and the Other Instruments.

Description

Stepless AC-DC converter

The invention belongs to a kind of ac-dc conversion device.

AC/DC convertor commonly used at present can be divided two big classes.One class is the linear stabilized power supply of band Industrial Frequency Transformer; Another kind of is high-frequency switching power supply.The former is owing to there is Industrial Frequency Transformer, so volume is big, Heavy Weight, efficient also low (see " transistor switch stabilized voltage power supply " 1985 version 2～4 pages).The latter then circuit complexity, output ripple is big, also exists the shortcoming of radio frequency interference.There is the requirement of pair components and parts also high again, for example, needs with high frequency devices (seeing " Switching Power Supply in the television set " 67～70 pages) such as high back-pressure high-frequency high-power switching tube, Schottky diode, big capacity high frequency capacitances.

The object of the present invention is to provide a kind of stepless AC-DC converter of transless power frequency switching regulator, this converter has the advantage of above-mentioned two kinds of power supplys concurrently, it can adopt the low frequency components and parts, and the mode that combines with linear voltage regulator with the low frequency switch realizes ac-dc conversion.

The present invention is made up of rectification circuit 1, synchronous high-voltage switch gear 2, control circuit 3, storage capacitor 4, filter 5 and linear voltage regulator 6, and as shown in Figure 1, Fig. 2 is a schematic diagram, and Fig. 3 is the oscillogram that Fig. 2 mainly puts.Below in conjunction with the description of drawings operation principle.

Rectification circuit 1 has two groups of rectification circuits, and one group is bridge heap 10, supplies with main circuit after the rectification, and another

organizes rectifier diode

11,12, and supply control circuit 3 after the rectification.

High-voltage switch gear 2 is one group of Darlington transistor synchronously, forms (Fig. 2) by two triodes; Also can use MOS device (Fig. 4); Or ambipolar and MOS mixing (Fig. 5); Or turn-off SCR (Fig. 6).

Control circuit 3 is one group of Schmidt trigger circuit and soft starting circuit and protective circuit, is gone to control the conducting or the disconnection of two synchronous high-voltage switch gears 2 by buffering triode 41 by Schmidt trigger circuit.Control circuit 3 also can adopt MOS transistor (Fig. 7) or integrated schmidt trigger (Fig. 8) or controllable silicon and transistor combination (Fig. 9).

Storage capacitor 4 is connected on the back of synchronous high-voltage switch gear 2, and its minimum capacity is determined by maximum load current.If from improving the efficient of power supply, under the situation that the current capacity of high-voltage switch gear allows synchronously, the storage capacitor amount is selected to heal, and greatly then efficient is higher.

Filter 5 can be selected capacitance-resistance filter or inductance capacitor filtering according to filtering requirements.

Linear voltage regulator 6 can be selected integrated stable voltage circuit for use according to the requirement of power supply output, also can adopt discrete component to form.The present invention all can be integrated in the thick film circuit except that jumbo electric capacity.

After adding 220 volts of AC power, after rectification circuit 1 rectification, supply with major loop and control circuit 3 respectively, its figure is as shown in Figure 3.At t ₁-t ₂During this time, triode 34 ends, triode 37,41 conductings, and two synchronous high-voltage switch gears 2 are open-minded simultaneously, storage capacitor 4 chargings.Work as t=t ₂The time, the input voltage of Schmidt circuit begins to be higher than predetermined value, triode 34 conductings, and triode 37,41 ends, and two synchronous high-voltage switch gears 2 also end, and storage capacitor stops charging and to load discharge, arrives t=t ₃The time, repeat t=t again ₁The time process, the voltage waveform U on the storage capacitor 4 _B, as shown in Figure 3.This shows that the size of storage capacitor 4 capacity has determined the smoothness of waveform.Storage capacitor 4 output voltages are after filter 5 filtering, and waveform is more level and smooth.After passing through linear voltage regulator 6 voltage stabilizings again, then output is a straight direct voltage.The adjustment of output voltage can be with the resistance 30 and 31 and the ratio of resistance 33 and 36 that changes in the Schmidt circuit, and the voltage of change voltage-stabiliser tube 39 reaches.

Resistance 32 and electric capacity 38 are soft starting circuits, when alternating current rigidly connects when logical, if there is not soft starting circuit and since on the storage capacitor 4 this moment do not have voltage, the unexpected conducting of high-voltage switch gear synchronously, rush of current that will be very big to synchronous high-voltage switch gear; And after adding soft start, the voltage of Schmidt circuit establishes a process slowly, makes synchronous high-voltage switch gear 2 avoid impacting.

Controllable silicon 40 is used for the protection of power supply; when extraneous load variations generation overcurrent or short circuit; protective circuit (not drawing among the figure) is sent the control utmost point that signal is given controllable silicon 40; controllable silicon 40 conductings are the operating voltage short circuit of Schmidt circuit; triode 41 ends; two synchronous high-voltage switch gears 2 also end, and power supply no longer includes output.Eliminate when extraneous fault, power supply recovers normal output voltage again automatically.

Figure 10 is another schematic diagram of the present invention, only used a synchronous high-voltage switch gear in Figure 10, this is an optimum implementation of the present invention, when input voltage changes between 100V～250V, the direct current output that all can keep 112 volts 400 milliamperes is applicable to the electric plinth as colour TV

Owing to only adopt a synchronous high-voltage switch gear in the circuit, so circuit done corresponding change, and the base stage of direct and synchronous high-voltage switch gear 2 links to each other by 37 collector electrodes of the triode in the Schmidt circuit.The effect of the resistance 60 among Figure 10 is partly to have compensated the change in voltage that load current changes the output that causes.

Advantage of the present invention is that volume is little, in light weight, efficient is than higher, can adopt the low low frequency components and parts of price, circuit is also fairly simple, if the power supply as color television set can reduce cost and economize on electricity, because the production lot of television set is big, therefore good economic benefits and social benefit are arranged.It is estimated, as be used for colour tv power supply, every power supply can reduce cost 10 yuan at least, as produces 5000000 per year, then can save 5,000 ten thousand yuan every year.

Embodiment:

Figure 10 is the embodiment that the present invention can be used for colour tv power supply, is input as to exchange 220 volts, is output as 112 volts 400 milliamperes direct voltage.Each component parameter of Fig. 4 is as follows:

Resistance 30 100K

Resistance 31 10K

Resistance 32 500K

Resistance 33 68K

Resistance 35 2K

Resistance 36 4.3K*

Resistance 43 30K

Resistance 60 2 Ω/1W

Resistance 61 10K

Resistance 63 2K

Resistance 68 62K

Resistance 69 24K*

Triode 34 3DG6

Triode 37 3DG160C BVceo＞400V

Triode 21 3CG184G

Triode 22 3DD167G

Triode 65,67 3DG180 * 2

Triode 64 DD01D

Rectifier bridge is piled 10 400V3A

Diode

11,12,44,66 1N4007 * 4

Voltage-stabiliser tube 39 35V

Electric capacity 38 20 μ F/50V

Electric capacity 4 120 μ F/160V

Electric capacity 62,70 10 μ F/160V * 2

Claims

1, a kind of stepless AC-DC converter, form by rectification circuit 1, synchronous high-voltage switch gear 2, control circuit 3, storage capacitor 4, filter 5 and linear voltage regulator 6, it is characterized in that its emitter resistance 35 of Schmidt trigger circuit in the control circuit 3 receives the base stage of triode 41, the collector and emitter of triode 41 is received the base stage of two synchronous high-voltage switch gears 2 respectively by resistance 42; Capacitor 38, voltage-stabiliser tube 39 and controllable silicon 40 backs in parallel one end ground connection.The collector electrode of another termination triode 37 and resistance 32,33, the silicon controlled control utmost point connects protective circuit.

2, AC/DC convertor according to claim 1, it is characterized in that said two synchronous high-voltage switch gears 2 also can be only with a synchronous high-voltage switch gear that is connected on power positive end, remove triode 41 and resistance 42 this moment, the collector electrode of triode 37 and other element disconnect and join with the base stage of synchronous high-voltage switch gear 2.

3, AC/DC convertor according to claim 1 is characterized in that said synchronous high-voltage switch gear 2 also can replace with mixing or the turn-off SCR of MOS device or ambipolar and MOS.

4, AC/DC convertor according to claim 1 is characterized in that the Schmidt trigger in the control circuit 3 also can be used MOS transistor circuit or integrated schmidt trigger or controllable silicon and transistorized joint line.

5, AC/DC convertor according to claim 1 is characterized in that the rectifier bridge heap 10 in the rectification circuit 1 outputs to synchronous high-voltage switch gear 2, and another road rectification is through rectifier diode 11,12 supply control circuits 3.

6, AC/DC convertor according to claim 1 is characterized in that storage capacitor is connected on the output of synchronous high-voltage switch gear 2.

7, AC/DC convertor according to claim 1 is characterized in that filter 5 can be capacitance-resistance filter or inductance capacitor filtering.