CN206743112U - A kind of low cost and high reliability Yi nationality medicine production isolation type switch power - Google Patents

Abstract

The utility model discloses a kind of low cost and high reliability Yi nationality medicine production isolation type switch power, and current rectifying and wave filtering circuit couples with power end U1 ends and control circuit, and remote control switching circuit couples controlling switch with control circuit；The transformer Ta2 coils L1 of control circuit couples with after the parallel connection of series capacitance C4, R3 with current rectifying and wave filtering circuit and triode T4 colelctor electrodes, triode T4 base stages cross that series resistance R2, R4 are coupled with current rectifying and wave filtering circuit and grounded emitter, coil L3 are connected with power output end U0；Self-oscillation positive feedback unit couples with start unit and crosses transformer Ta2 and circuit to improve output power of power supply; pwm unit is coupled by triode T2, T3, phototriode OC and circuit with start unit realizes that power supply exports voltage stabilizing; protection location is coupled by circuit with start unit, positive feedback unit and pwm unit to form protection, and voltage regulation unit exports voltage stabilizing by triode T5 and circuit to power supply.

Description

A kind of low cost and high reliability Yi nationality medicine production isolation type switch power

Technical field

The utility model belongs to switch power technology field, and in particular to one kind has simple in construction, inexpensive, highly reliable Property low cost and high reliability Yi nationality medicine production isolation type switch power.

Background technology

With the high speed development of electronic technology, the application field of electronic system is more and more extensive, the species of electronic equipment More and more, the work of electronic equipment and people, the relation of life are increasingly close.Circuit in modern electronic equipment has used greatly The semiconductor devices of amount, these semiconductors need several volts to tens volts of direct current supplys, necessary to obtaining normal work The energy.These dc source some belong to electrochmical power source, such as use dry cell and battery, but these persistent can not be supplied Electricity.The direct current supply method of most of electronic equipments is all to be transformed to AC power by transformation, rectification, filtering, voltage stabilizing etc. Required DC voltage, completing the power supply of this transformation task turns into D.C. regulated power supply.Any electronic equipment all be unable to do without can The power supply leaned on, with the development of technology, their requirements to power supply also more and more higher.Traditional linear stabilized power supply has stable Performance is good, output voltage ripple is small, using it is reliable the advantages that, but its be generally required for Industrial Frequency Transformer that volume is necessarily large and bulky with The all very big wave filter of volume and weight.In addition, the adjustment pipe work in traditional circuit is in linear magnifying state, it is defeated in order to ensure Go out voltage stabilization, larger voltage difference is must endure as between its colelctor electrode and emitter stage, cause the power consumption for adjusting pipe larger, power supply Efficiency is very low, and general only 45% or so.Further, since larger power is consumed on adjustment pipe, so needing using high-power Adjustment is managed and sufficiently bulky radiator is housed, it is difficult to meet the needs of modern electronic equipment development.

Switching Power Supply is a kind of D.C. regulated power supply controlled using on-off mode, is adjusted by the dutycycle of controlling switch Whole output voltage.It is widely used in using electronic computer as leading various ends using small-sized, light weight and efficient feature The almost all of electronic equipment such as end equipment, communication equipment, it is that current electronics and information industry develops rapidly indispensable one kind Form of power.The D.C. regulated power supply used in modern electronic equipment has two major classes：Linear stabilized power supply and switch property voltage stabilizing electricity Source.So-called linear stabilized power supply is exactly that its adjustment pipe work is in linear amplification region, the most important shortcoming of this voltage-stabilized power supply Conversion efficiency is low, and typically only 35 ~ 60% or so.The switching tube of switching power supply is operated on off state, and it is main excellent More property is exactly that conversion efficiency is high, and up to 70 ~ 95%.

Modern Yi nationality's medicine is wide in variety, specification is few due to typically belonging to minority's product, and production equipment typically all uses middle or small work( The equipment of rate.In the prior art, switch property voltage-stabilized power supply is used as the core of switch voltage-stabilizing unit using discharge circuit more, i.e., Front stage circuits carry out input signal detection, and rear class amplifier will input the signal detected compared with default benchmark, so as to Reach the purpose that power supply output is closed in control；Also have and carry out input signal detection using several transistor control circuits, i.e. prime, Rear class is simply amplified the signal that input detects with triode, reaches the purpose that power supply output is closed in control.But study It was found that it is higher as isolation type switch power cost using discharge circuit, it is uncomfortable in the medium and small power power-supply of Yi nationality's medicine production With；And although the traditional transistor control circuit of use is relatively low as signal amplification cost, due to lacking necessary protection and control Making mechanism, it is also difficult to meet the requirement of the Switching Power Supply control accuracy of modern Yi nationality's medicine production equipment.

Utility model content

The purpose of this utility model is to provide a kind of low cost and high reliability simple in construction, inexpensive, high reliability Yi nationality's medicine production isolation type switch power.

What the purpose of this utility model was realized in：Including current rectifying and wave filtering circuit, control circuit, remote control switching circuit, The current rectifying and wave filtering circuit input is coupled with power supply U1 ends and output end couples with the input of control circuit, and the remote control is opened The output end on powered-down road is coupled with control circuit to control the closing of control circuit or open-minded；The control circuit includes starting list Member, self-oscillation positive feedback unit, pwm unit, protection location, voltage regulation unit, it is primary that the start unit includes first Coil L1, the first secondary coil L3 transformer Ta2, the first primary coil L1 and electric capacity C4, the resistance R3 to connect are in parallel Both ends couple with the output end of current rectifying and wave filtering circuit and triode T4 colelctor electrode respectively afterwards, and the base stage of the triode T4 passes through Series resistance R2, resistance R4 couple with the output end of current rectifying and wave filtering circuit, the grounded emitter of the triode T4, and described first Secondary coil L3 is connected with power output end U0；The self-oscillation positive feedback unit and start unit coupling merga pass transformer Ta2 and accessory circuit increase triode T4 base current improve power supply output to increase the first primary coil L1 energy storage Hold U0 power output, the pwm unit by triode T2, triode T3, phototriode OC and accessory circuit with Start unit coupling realizes power output end U0 voltage stabilizing to adjust triode T4 dutycycle, and the protection location passes through electricity Hold, resistance and diode are coupled to triode therein with start unit, self-oscillation positive feedback unit and pwm unit Protection is formed, the voltage regulation unit carries out voltage stabilizing by triode T5 and accessory circuit to power output end U0.

The utility model has the advantages that compared with prior art：

1st, the utility model is compared with discharge circuit and traditional triode control, by using simple, reliable and inexpensive Triode, transformer, phototriode and electric capacity, resistance, the electrical equipment such as diode reasonably optimizing combination, with low cost Realize Switching Power Supply have output stability can it is good, output voltage ripple is small, complete neat and compact-sized using reliable, safeguard measure Advantage；

2nd, the utility model passes through start unit, self-oscillation positive feedback unit, pwm unit, guarantor in control circuit Sharing for unit and each electrical equipment of voltage regulation unit is protected, overall structure is further simplify and reduces cost, and improve The conversion efficiency and reliability of Switching Power Supply, so that the utility model can be good at meeting modern Yi nationality's medicine production etc. In, requirement of the low-power equipment to Switching Power Supply.

Therefore, the utility model has the characteristics of simple in construction, inexpensive, high reliability.

Brief description of the drawings

Fig. 1 is that the utility model is electrically connected schematic diagram；

The start unit that Fig. 2 is Fig. 1 is electrically connected schematic diagram；

The self-oscillation positive feedback unit that Fig. 3 is Fig. 1 is electrically connected schematic diagram；

The pwm unit that Fig. 4 is Fig. 1 is electrically connected schematic diagram；

The protection location that Fig. 5 is Fig. 1 is electrically connected schematic diagram；

The voltage regulation unit that Fig. 6 is Fig. 1 is electrically connected schematic diagram；

The remote control switching circuit that Fig. 7 is Fig. 1 is electrically connected schematic diagram.

Embodiment

The utility model is further described with reference to the accompanying drawings and examples, but not in any way to this practicality Any changes and modifications that are new to be any limitation as, being made based on the utility model training centre, belong to protection model of the present utility model Enclose.

As shown in Fig. 1 to 7, the utility model includes current rectifying and wave filtering circuit, control circuit, remote control switching circuit, described whole Stream filter circuit input is coupled with power supply U1 ends and output end couples with the input of control circuit, the remote control switching circuit Output end coupled with control circuit to control the closing of control circuit or open-minded；The control circuit include start unit, from Impulse and swing positive feedback unit, pwm unit, protection location, voltage regulation unit, the start unit includes the first primary coil L1, the first secondary coil L3 transformer Ta2, the first primary coil L1 with connect electric capacity C4, two after resistance R3 parallel connections End couples with the output end of current rectifying and wave filtering circuit and triode T4 colelctor electrode respectively, and the base stage of the triode T4 passes through series connection Resistance R2, resistance R4 couple with the output end of current rectifying and wave filtering circuit, the grounded emitter of the triode T4, first level Coil L3 is connected with power output end U0；The self-oscillation positive feedback unit and start unit coupling merga pass transformer Ta2 And accessory circuit increase triode T4 base current is to increase the first primary coil L1 energy storage to improve power output end U0 power output, the pwm unit is by triode T2, triode T3, phototriode OC and accessory circuit with opening Moving cell coupling realizes power output end U0 voltage stabilizing to adjust triode T4 dutycycle, and the protection location passes through electricity Hold, resistance and diode are coupled to triode therein with start unit, self-oscillation positive feedback unit and pwm unit Protection is formed, the voltage regulation unit carries out voltage stabilizing by triode T5 and accessory circuit to power output end U0.

The utility model also includes gripping magnetic filter circuit, and the input for gripping magnetic filter circuit couples and defeated with power supply U1 Go out end coupled with the input of current rectifying and wave filtering circuit, it is described grip magnetic filter circuit including coupled with power supply U1 common mode inductance Ta1, The electric capacity C1 coupled with mould inductance Ta1 output ends.

The current rectifying and wave filtering circuit include rectifier bridge stack UR, electric capacity C2, electric capacity C3, the input of the rectifier bridge stack UR with Common mode inductance Ta1 output end coupling, is coupled after electric capacity C2 and electric capacity the C3 parallel connections with rectifier bridge stack UR output end, described Electric capacity C2 capacity is much smaller than electric capacity C3.

As shown in figure 3, the self-oscillation positive feedback unit includes the circuit of start unit, containing the second primary coil L2's Transformer Ta2, the resistance R2 output end be sequentially connected in series electric capacity C5, resistance R5 and with the second primary coil L2 input Coupling, the output end of the second primary coil L2 are connected with triode T4 emitter stage, the electric capacity C5 and resistance of the series connection R5 is also parallel with reverse diode D2.

As shown in figure 4, the pwm unit includes circuit, the coil containing second subprime of self-oscillation positive feedback unit L4 transformer Ta2, triode T2, triode T3, triode T5, phototriode OC, the colelctor electrode of the triode T2 with Resistance R2 output end couples and emitter stage couples with triode T3 base stage, the base stage and phototriode of the triode T2 Transistor collector couples in OC, and the colelctor electrode of the triode T3 is coupled with triode T4 base stage and grounded emitter, institute The input for stating second of primary coil L2 is coupled and exported with triode T3 base stage by the resistance R8 of series connection, diode D4 End ground connection, the output end of the first secondary coil L3 pass sequentially through the diode D6, resistance R12, variable resistor D8 of series connection with Triode T5 base stage coupling, the emitter stage of the triode T5 pass through reverse voltage-regulator diode D7 ground connection and colelctor electrode and light The positive pole of light emitting diode couples in electric triode OC, the negative pole series diode of light emitting diode in the phototriode OC R16 is grounded and transistor emitter therein is grounded.

The input of second of primary coil L2 is connected with output end and is followed by by resistance R11, the electric capacity C9 of parallel connection Ground, the input of the diode R16 are coupled by resistance R15 with the first secondary coil L3 output end, the triode T2 Base series resistor R1 coupled with colelctor electrode and emitter stage is grounded by resistance R9.

As shown in figure 5, the protection location include electric capacity C6, electric capacity C7, the electric capacity C6 both ends respectively with triode T3 collector and emitter coupling, the input of second of primary coil L2 pass through the resistance R6 of series connection, reverse steady Pressure diode D3 coupled with triode T3 base stage, one end of the electric capacity C7 coupled with voltage-regulator diode D3 input and separately One end couples with triode T3 emitter stages.

As shown in fig. 6, the voltage regulation unit by the triode T2 in pwm unit, triode T3, triode T4, Triode T5, phototriode OC, voltage-regulator diode D3, voltage-regulator diode D7 and accessory circuit carry out steady to power output end U0 Pressure output.

As shown in fig. 7, the remote control switching circuit includes triode T6, the triode T6 base stage and switch control letter Number coupling and grounded emitter, colelctor electrode couple with triode T5 colelctor electrode and coupled by resistance R17 with supply voltage.

The the first primary coil L1 and the second primary coil L2 of the transformer Ta2 voltage ratio are 1：3, at the beginning of described first Level coil L1 and the first secondary coil L3 voltage ratio is 1：2, the electricity of the first primary coil L1 and second subprime the coil L4 Pressure ratio is 1：2.

Utility model works principle and the course of work：

The utility model by using simple, reliable and inexpensive triode, transformer, phototriode and electric capacity, The electrical equipments such as resistance, diode are respectively constituted in current rectifying and wave filtering circuit, control circuit, remote control switching circuit and control circuit Start unit, self-oscillation positive feedback unit, pwm unit, protection location and voltage regulation unit, it is defeated to be realized with a low cost Go out that stability is good, output voltage ripple is small, complete neat and compact-sized using reliable, safeguard measure；In addition, pass through control circuit Middle start unit, self-oscillation positive feedback unit, pwm unit, protection location and each electrical equipment of voltage regulation unit are total to With, it further simplify overall structure and reduce cost, also improve the conversion efficiency and reliability of Switching Power Supply, so as to Enough meet well in modern Yi nationality's medicine production etc., requirement of the low-power equipment to Switching Power Supply.Further, rectifying and wave-filtering Circuit is preposition to grip magnetic filter circuit, can effectively suppress electric network noise, improves the antijamming capability and reliability of Switching Power Supply.Enter one Step, current rectifying and wave filtering circuit includes rectifier bridge stack UR and rearmounted small capacitances C2 and bulky capacitor C3 in parallel, can either effectively filter Except low frequency and high frequency spurs, and the volume of electric capacity can also be reduced to improve integrally-built compactedness.Further, impulse certainly Swinging positive feedback unit includes the circuit and accessory circuit of start unit, and pwm unit includes self-oscillation positive feedback unit Circuit and accessory circuit, protection location between the triode T3 of pwm unit collector and emitter shunt capacitance C6 with And series capacitance C7, remote control switching circuit pass through between triode T2 emitter stages and ground connection between triode T3 colelctor electrodes and ground connection The triode T5 of triode T6 and pwm unit emitter stage connection；So as to electric by identical function in above each unit Element shares, and further simplify overall structure and reduces cost, also improves the conversion efficiency of Switching Power Supply and reliable Property.In summary, the utility model has the characteristics of simple in construction, inexpensive, high reliability.

As shown in Fig. 1 to 7,220V/50HZ civil powers are inputted, because network load occurs larger increase or decrease Cause voltage pulsation, frequency also there are many frequency waves, so by entering in the preposition magnetic filter circuit of gripping of current rectifying and wave filtering circuit to it Row filtering.Acted on using the conduct current of diode, bridge is formed using four diodes in the rectifier bridge stack of current rectifying and wave filtering circuit Formula rectifier structure so that in the positive and negative half cycle of AC power, there is the constant pulsating direct current in direction in the load of rectification circuit Voltage and current.Voltage after rectification can calculate：U1=0.9*Ui*cosα≈300V.Select pressure-resistant two poles for 300V Pipe is with regard to that can meet the requirement of rectification.After rectification, caused is a pulsating dc voltage, but Switching Power Supply it is desirable that than Compared with steady dc voltage, so typically utilizing 50 μ F small capacitances C2 and more than 100 μ F bulky capacitor C3 to the electricity after rectification Stream undertakes low frequency filtering, High frequency filter respectively, and it is that a fluctuation is smaller to make output voltage, and substantially one than shallower DC voltage.

Start unit provides condition for the startup of whole Switching Power Supply.Using resistance R2 and R4 two big, triode T4 Turn on, it is necessary to provide it with a base current, and this branch road is exactly 300V voltages is added on R2, R4, gives triode T4 Base stage provides an electric current, forms electric current by T4 be emitter junctions, opens switch transistor T 4.As for the big of T4 base currents Small, this can be calculated：General power taking resistance R2 is 199K Ω, and R4 is 100K Ω, R2, R4 series connection, because the decompression on be sections Very little, it is possible to which that regards as directly adds 300V voltages thereon, according to Ohm's law：I=U/R obtains I=1.5mA.Many times, Different voltages are provided for other circuits or provide voltage to protection circuit, are all that R2 is in series by several small resistors.

Required T4 base currents are 1.5mA above, and the multiplication factor of triode is typically all tens times, so three poles The collector current of pipe also just only tens milliamperes, this electric current can not much meet our normal work needs, in order to increase The power output of big Switching Power Supply, it is necessary to improve the electric current flowed through among inductance coil, that is to say, that make more storages in inductance coil Deposit magnetic field energy.Because the electric current of colelctor electrode and its base current are to be mutually related, the electric current of colelctor electrode is improved, must just be carried The base current of high triode, if base current does not increase, the collector current of triode is also just no to be increased. In order to improve triode T4 base current, increase self-oscillation positive feedback unit herein.It is triode T4 in start unit Base stage provide certain electric current after, have certain electric current under conditions of in triode T4 colelctor electrode, it is primary first Energy is stored on coil L1, produces a texture electromotive force, and be coupled on the second primary coil L2, the texture electromotive force on L2 Charge with forming electric current to electric capacity C5, after charging complete, electric current can be added on triode T4 be sections by diode D2, this Sample, the base current of triode is just increased, the electric current of colelctor electrode in any case also can be with increase, also with regard to that can increase L1 On energy storage, and then meet switched power output connection equipment normal work needs.

Steady dc voltage is obtained, that is, when input voltage changes, output voltage stabilization is constant.For Triode, thus it is possible to vary dutycycle, that is, switch conduction and the time ratios of closing, it is possible to change the big of output voltage It is small, in addition, changing the dutycycle of switching tube, it can also realize voltage stabilizing.Using pwm unit by shunting adjustment pipe T3 and electricity Road is to change triode T4 dutycycle.When output voltage raises, the light emitting diode in photoelectrical coupler OC will be sent out Light, while triode therein will also turn on, and will provide an electric current to triode T2 base stage and be allowed to turn on, triode T2 conducting can provide a base current to triode T3, and T3 is turned on and T4 base currents are shunted therewith, and then is subtracted The electric current of the colelctor electrode of small switch transistor T 4, it also just can reduce the energy storage on the first primary coil L1, reduce output voltage, realize Pressure stabilization function.Wherein, limit value resistance when diode R7 and R9 is shunting adjustment pipe T3 normal works.And output voltage reduces When, the light emitting diode in photoelectrical coupler OC does not light, and triode therein would not also turn on, then shunting adjustment pipe T3 Also would not turn on.

Because triode is easy to damage in time circuit, protection location is set to the triode in circuit.Work as switch When triode T4 ends, the first primary coil L1 will induce a just upper negative electromotive force under one, and at the beginning of second Level coil L2 can also induce just upper negative electromotive force under one, because the electromotive force of sensing is very big, so can be to triode Be sections cause very big threat.Therefore, in a triode T3 be both ends bulky capacitor C6 in parallel, when L2 is induced under one When just upper negative electromotive force, the upper just lower electric capacity born that is filled when will turn on switch triode before to bulky capacitor C6 Neutralize, because capacitance voltage can not be mutated, the electromotive force that L2 is induced can not be such that capacitance voltage is raised from moment, T3's Voltage between be can not be raised moment, and C6 electric capacity is protected with regard to energy switch tube T3.Similarly, electric capacity C7 also can be to T3 be Section is protected.Diode D4 and resistance R8 effect are to form discharge loop to L2, to avoid caused texture voltage in L2 It can not discharge, circuit is damaged.In addition, electric capacity C4 and resistance R3 are also protection circuit, when triode T4 ends, Electric current pop-off on its colelctor electrode, but L1 electric current will not pop-off, discharge loop is formed by C4 and R3 to shunt Very big voltage caused by its moment, so as to protect triode T4.

When the line voltage rise of input, output loading or switching power circuit for protection switch power supply, Exactly output voltage is not influenceed by input voltage fluctuation, increase the overvoltage that voltage-regulator diode D3 and resistance R6 is formed and protect Unit is protected, when stabilized input voltage, this unit does not work, and only when input voltage raises, unit can just work.Its Voltage and input voltage on middle L1 almost directly proportional, and the texture voltage on L2 is and the texture voltage change ratio on L1 For 3：1, namely be 100V under normal circumstances, on L2, this when, voltage-regulator diode will not just puncture.When input voltage liter When high, the texture voltage on L2 can also raise, and more than 100V, if without this protection location, voltage increases on L2 Greatly, the base voltage on T1 3 will be increased, the base current increase on T13, the voltage on its colelctor electrode also can be with increasing Greatly, then the electric current on inductance coil also increases, and the energy of storage can also increase, and the texture electromotive force on L2 is also increased, Increase the electric current on L1 again in turn, be so likely to burn out circuit element, protected so an overvoltage must be increased Protect unit.In the case where there is overvoltage protective unit, when input voltage raises, the texture voltage on L2 can also raise, but because A voltage-regulator diode for D3, when voltage exceedes its pressure voltage, voltage-regulator diode will be breakdown and turn on, this Sample electric current just passes through resistance R6 and voltage-regulator diode D3, flows through T3 base stage and emitter stage, and T3 mono- is turned on, and its colelctor electrode also will There is electric current, also just divide a part of base current for having removed triode T4, T4 base current reduces, and may result in its colelctor electrode Electric current reduce, the energy storage on such L1 can also reduce so that voltage reduces, and this automated procedure is achieved that to input voltage Overvoltage protection.

Voltage regulation unit, exactly when input voltage changes, circuit makes output voltage stabilization constant automatically.Assuming that input Voltage raises, and output voltage is also just with rise, and the voltage between R15, R16 can also raise, due to voltage-regulator diode D7 electricity Pressure can not be mutated, so the voltage of triode T5 be internodes can also raise, T5 conducting degree will increase, photoelectricity three Pole pipe OC is also turned on, lumination of light emitting diode, excites the triode ON in OC, and T2 is also turned on and provided base stage electricity to T3 Stream, after T3 conductings, its colelctor electrode just has electric current, also T4 base current can be shunted, T4 base current subtracts therewith Small, its collector current can also reduce, and the energy stored in L1 also can accordingly reduce, and output voltage will also reduce, realization pair The automatic voltage regulation effect of output voltage.

CPU exports base stage of the high level to triode T6 in remote control switching circuit, then its colelctor electrode is just low electricity It is flat, the LEDs ON in OC can be caused to light, the luminous of Light-Emitting Diode makes triode saturation conduction therein, will Give T2 to provide a very big base current, T2 also saturation conductions, and then T3 also will saturation conduction, during T3 saturation conductions, its Voltage between collector and emitter only has 0.3V or so, and to cause T4 to turn on, L1 would not also be stored this undertension Energy, then also just do not have output voltage, Switching Power Supply would not also work, and therefore, when CPU exports high level, open Powered-down source is in order at off-mode.When CPU output level is low level, T6 cut-offs, remote control switching circuit is just to whole Individual Switching Power Supply does not influence, then this power supply will normal work, output end just has output voltage.

Claims (10)

1. a kind of low cost and high reliability Yi nationality medicine production isolation type switch power, it is characterised in that including current rectifying and wave filtering circuit, control Circuit processed, remote control switching circuit, the current rectifying and wave filtering circuit input is coupled with power supply U1 ends and output end and control circuit Input is coupled, and the output end of the remote control switching circuit is coupled with control circuit to control the closing of control circuit or open-minded； The control circuit includes start unit, self-oscillation positive feedback unit, pwm unit, protection location, voltage regulation unit, institute State start unit include the first primary coil L1, the first secondary coil L3 transformer Ta2, the first primary coil L1 with After the electric capacity C4 of series connection, resistance R3 parallel connections both ends respectively with the output end of current rectifying and wave filtering circuit and triode T4 colelctor electrode coupling Close, the base stage of the triode T4 is coupled by series resistance R2, resistance R4 with the output end of current rectifying and wave filtering circuit, three pole Pipe T4 grounded emitter, the first secondary coil L3 are connected with power output end U0；The self-oscillation positive feedback unit It is primary to increase first with start unit coupling merga pass transformer Ta2 and accessory circuit increase triode T4 base current Coil L1 energy storage improves power output end U0 power output, and the pwm unit passes through triode T2, three poles Pipe T3, phototriode OC and accessory circuit couple with start unit realizes that power supply exports to adjust triode T4 dutycycle U0 voltage stabilizing is held, the protection location passes through electric capacity, resistance and diode and start unit, self-oscillation positive feedback unit and arteries and veins Wide modulating unit coupling is formed to triode therein to be protected, and the voltage regulation unit is by triode T5 and accessory circuit to power supply Output end U0 carries out voltage stabilizing.

2. low cost and high reliability Yi nationality medicine production isolation type switch power according to claim 1, it is characterised in that also include Magnetic filter circuit is gripped, the input for gripping magnetic filter circuit is coupled with power supply U1 and the input of output end and current rectifying and wave filtering circuit End coupling, it is described to grip common mode inductance Ta1 that magnetic filter circuit includes coupling with power supply U1, couple with mould inductance Ta1 output ends Electric capacity C1.

3. low cost and high reliability Yi nationality medicine production isolation type switch power according to claim 2, it is characterised in that described whole Flowing filter circuit includes rectifier bridge stack UR, electric capacity C2, electric capacity C3, the rectifier bridge stack UR input with common mode inductance Ta1's Output end couples, and is coupled after electric capacity C2 and electric capacity the C3 parallel connections with rectifier bridge stack UR output end, the electric capacity C2 capacity is remote Less than electric capacity C3.

4. according to claim 1 low cost and high reliability Yi nationality medicine production isolation type switch power, it is characterised in that it is described from Impulse and swing positive feedback unit and include circuit, the transformer Ta2 containing the second primary coil L2 of start unit, the resistance R2's Output end is sequentially connected in series electric capacity C5, resistance R5 and coupled with the second primary coil L2 input, the second primary coil L2 Output end be connected with triode T4 emitter stage, the electric capacity C5 and resistance R5 of the series connection are also parallel with reverse diode D2。

5. low cost and high reliability Yi nationality medicine production isolation type switch power according to claim 4, it is characterised in that the arteries and veins Wide modulating unit include the circuit of self-oscillation positive feedback unit, the L4 of coil containing second subprime transformer Ta2, triode T2, Triode T3, triode T5, phototriode OC, the colelctor electrode of the triode T2 are coupled and launched with resistance R2 output end Pole couples with triode T3 base stage, and the base stage of the triode T2 couples with transistor collector in phototriode OC, institute The colelctor electrode for stating triode T3 couples and grounded emitter with triode T4 base stage, the input of second of primary coil L2 End passes through the resistance R8 to connect, diode D4 is coupled with triode T3 base stage and output head grounding, first secondary coil The diode D6, resistance R12, variable resistor D8 that L3 output end passes sequentially through series connection couple with triode T5 base stage, described Triode T5 emitter stage passes through reverse voltage-regulator diode D7 ground connection and colelctor electrode and light emitting diode in phototriode OC Positive pole coupling, the negative pole series diode R16 ground connection of light emitting diode and triode therein in the phototriode OC Grounded emitter.

6. low cost and high reliability Yi nationality medicine production isolation type switch power according to claim 5, it is characterised in that described the Secondary primary coil L2 input is grounded after being connected by resistance R11, the electric capacity C9 of parallel connection with output end, the diode R16 input is coupled by resistance R15 with the first secondary coil L3 output end, the base series resistor of the triode T2 R1 is coupled with colelctor electrode and emitter stage is grounded by resistance R9.

7. isolation type switch power is produced according to the low cost and high reliability Yi nationality medicine of claim 5 or 6, it is characterised in that described Protection location couples including the collector and emitter of electric capacity C6, electric capacity C7, the electric capacity C6 both ends respectively with triode T3, The input of second of primary coil L2 passes through resistance R6, the reverse voltage-regulator diode D3 of series connection and triode T3 base Pole couples, and one end of the electric capacity C7 is coupled with voltage-regulator diode D3 input and the other end and triode T3 emitter stage couplings Close.

8. isolation type switch power is produced according to the low cost and high reliability Yi nationality medicine of claim 5 or 6, it is characterised in that described Voltage regulation unit by the triode T2 in pwm unit, triode T3, triode T4, triode T5, phototriode OC, Voltage-regulator diode D3, voltage-regulator diode D7 and accessory circuit carry out voltage stabilizing output to power output end U0.

9. isolation type switch power is produced according to the low cost and high reliability Yi nationality medicine of claim 5 or 6, it is characterised in that described Remote control switching circuit includes triode T6, and the base stage of the triode T6 is coupled with switch controlling signal and grounded emitter, collection Electrode is coupled with triode T5 colelctor electrode and coupled by resistance R17 with supply voltage.

10. isolation type switch power is produced according to the low cost and high reliability Yi nationality medicine of claim 5 or 6, it is characterised in that institute The voltage ratio for stating transformer Ta2 the first primary coil L1 and the second primary coil L2 is 1：3, the first primary coil L1 Voltage ratio with the first secondary coil L3 is 1：2, the first primary coil L1 and second subprime the coil L4 voltage ratio are 1： 2。