CN2323528Y - Intelligent facsimile apparatus protector - Google Patents

Abstract

The utility model relates to a fax machine protector controlled by a single-chip microcomputer. Under the action of the protector, the fax machine is not powered up to work at ordinary times and only powered up to work when sending and receiving faxes. The protector has the functions of voltage-stabilizing protection, limitation on surge current when the fax machine is in soft start, lightning protection, theft-protection telephone lines and low power consumption. The utility model comprises a DC circuit for AC Power input protection and low voltage, an over-voltage protecting circuit for AC Power output soft start, an AC output voltage/frequency converting circuit, a single chip computer circuit, a ringing detecting circuit, a theft protecting line, an interface circuit of a telephone line, an off-hook detecting circuit of the fax machine, a time-delay control circuit of the telephone line and an off-hook detecting circuit of a telephone.

Description

The intelligent facsimile motor protector

The utility model relates to a kind of facsimile machine protector, particularly a kind of facsimile machine protector with controlled by single chip microprocessor.

To can not receive fax in order preventing when unattended at present, generally, to power up work continuously for a long time all with the start in 24 hours of facsimile machine whole day.So not only expense electricity but also quickened the aging of components and parts in the facsimile machine has shortened the useful life of facsimile machine.If AC supply voltage surpasses 230 volts, especially under summer indoor temperature condition with higher, make the long-term continuous operation of facsimile machine again, easily cause the damage of facsimile machine.

In order to address this problem, the unit that has once developed " facsimile machine protector ".As: the 39th page of facsimile machine protector of being introduced of electronics newspaper nineteen ninety-five bound volume volume two.Its function is: power to facsimile machine automatically when receiving or send fax; Reception or transmission finish, and delay time for tens seconds, and machine cuts off the power supply automatically.But this protector reliability is very poor, can't promote the use of.Reason is: this protector is to receive outside line signal output low level by optocoupler 4n25 to trigger 555 time-base circuits, makes its 3 pin output high level drive actuating of relay and to the facsimile machine power supply.When this circuit was sent into tens volts ringing voltage in outside line, it was feasible making 4N25 conducting output low level.But it is impracticable leaning on the facsimile signal level to make 4N25 keep conducting.Because by this circuit test, input facsimile signal voltage is greater than 1.7V just can make 4N25 conducting output low level, and the real output signal voltage of facsimile machine is generally all below 1V.

The purpose of this utility model is in order to overcome the defective of above-mentioned prior art, and a kind of multiple functional, highly reliable, intelligent, facsimile machine protector cheaply with controlled by single chip microprocessor is provided; So that facsimile machine does not power up work at ordinary times, just power up work when having only fax sending and receiving; And having the superpressure voltage-stabilizing protection, facsimile machine start soft start carries out inrush current limitation, anti-lightning strike protection and antitheft with advanced functions such as telephone wire, low-power consumption.

The purpose of this utility model is to be realized by the device of the following architectural feature that limits.1. intelligent facsimile motor protector, it is characterized in that control circuit is that core constitutes with the single chip circuit, AC power input protection and its output of low-voltage dc circuit input termination civil power connect single chip circuit and AC power output soft start and overpressure protection circuit, and the output of AC power output soft start and overpressure protection circuit connects ac output voltage/frequency-conversion circuit and facsimile machine power circuit; The output order sheet machine circuit of ac output voltage/frequency-conversion circuit; Telephone wire is connected to single chip circuit by telephone line interface circuit, ring detecting circuit, and telephone line interface circuit also is connected with telephone line circuitry, facsimile machine off-hook detection circuit, telephone set off-hook detection circuit with antitheft; Facsimile machine off-hook detection circuit links to each other with telephone wire by delay control circuit, and the delay control circuit control end connects single chip circuit; Telephone set off-hook detection circuit also links to each other with single chip circuit with telephone wire; Antitheft output with telephone line circuitry links to each other with single chip circuit.2. as preceding paragraph 1 described intelligent facsimile motor protector, it is characterized in that the alternating current zero-detection circuit that described single chip circuit comprises the host scm integrated circuit, formed anti-jamming circuit and be made up of operational amplifier in resistance, diode and the single-chip microcomputer by monostable trigger.3. as preceding paragraph 1 described intelligent facsimile motor protector; it is characterized in that described AC power input protection and low-voltage dc circuit (A) comprise capacitor (C1; C2); the anti-lightning strike protective circuit that inductance (LF1) and piezo-resistance (VR1) are formed; transformer (T1) secondary (N2) and rectifier (BD2); capacitor (C5); resistor (R3) that form with the low-voltage dc circuit ground insulation, transformer (TI) secondary (N3); rectifier (BD1); resistor (R2); AC power zero crossing sample circuit and integrated regulator (IC3) and diode (D3) that diode (D2) is formed; capacitor (C3; C4) the latent volt circuit of the 5V of Zu Chenging.4. as preceding paragraph 1 described intelligent facsimile motor protector; it is characterized in that described AC power output soft start and overpressure protection electricity and ac output voltage/frequency-conversion circuit; comprise by field effect transistor, diode, resistor; the output soft starting circuit that rectifier is formed; by single-chip microcomputer, reach photoelectrical coupler, field effect transistor, rectifier) or the lowering and stabilizing blood pressure adjustment circuit of solid-state relay composition and output voltage/frequency-conversion circuit of forming by output voltage sampling transformer, rectifier, V/F converter.5. as preceding paragraph 1 described intelligent facsimile motor protector; it is characterized in that described ring detects and the antitheft telephone line circuitry of using; comprise polarity switching and the anti-lightning strike protective circuit formed by rectifier, capacitor, discharge diode; the ring detecting circuit of being made up of operational amplifier, diode, resistor, capacitor is antitheftly usurped telephone circuit with the phone line detection circuit with by the interference that triode, resistor, diode and single-chip microcomputer are formed by what operational amplifier, diode, resistor, capacitor were formed.6. preceding paragraph 1 described intelligent facsimile motor protector; it is characterized in that described off-hook detection and delay control circuit; comprise the facsimile machine off-hook detection circuit of forming by rectifier, photoelectrical coupler, telephone set off-hook detection circuit of forming by rectifier, photoelectrical coupler and the facsimile machine circuit delay control circuit of forming by triode, diode, relay.

The utility model compared with prior art has the following advantages: 1. adopt to have the new single chip microcomputer AT89C2051 of international most advanced level as this machine master controller.It is able to programme himself to have 2K byte flash, but erasable read only memory PEROM, and have 2 grades of program encryptions and low-power consumption, remarkable advantages such as the big electric current output of low level, ratio of performance to price height.Adopt single chip microcomputer to carry out the outside line bell signal detection, the facsimile machine off-hook detection reaches the facsimile machine power supply is controlled; Just make facsimile machine start work when having guaranteed to have only fax sending and receiving conscientiously, have high reliability, high accuracy.2. the anti-interference method that combines of hardware watchdog circuit and software watchdog, this machine functional reliability of making is guaranteed.3. invented by the AC power supply zero point testing circuit, output AC voltage/frequency translation high-accuracy sampling circuit, single-chip microcomputer, photoelectrical coupler, power field effect pipe, the AC power output soft starting circuit of novel voltage-dropping type AC voltage-stabilizing circuit that AC/DC convertor etc. are formed and restriction facsimile machine start surge current.This AC voltage-stabilizing circuit is different from various voltage stabilizing circuit of the prior art, be characterized in when AC-input voltage surpasses 220V, the number that dependence reduces half cycle of 50HZ AC power realizes exporting voltage stabilizing, the dependence servo direct current motor that extensively adopts with prior art in the small-power alternating current steady voltage plug below 1000W is regulated the mode of single-circuit transformer realization output voltage stabilizing and is compared, it is little to have volume, remarkable advantages such as in light weight, cost is low, simple in structure, manufacture easily.Carry out the mode of AC voltage-stabilizing with the size of control thyristor operating angle and compare, having does not have the high order harmonic component interference to AC network, belongs to the advantage that the pure sine wave voltage stabilizing is adjusted.When input ac power voltage is lower than 220 volts, because Switching Power Supply has the voltage stabilizing adjustment capability in the facsimile machine; So the present invention needn't carry out the low pressure voltage stabilizing.And when input ac voltage was higher than 220 volts, the switching loss of Switching Power Supply strengthened in the facsimile machine; When up to 240 volts when above, Switching Power Supply is operated in more than the limiting value in the facsimile machine, as at this moment the AC power of supplying with facsimile machine not being carried out lowering and stabilizing blood pressure, particularly start work under the environment of indoor high temperature in summer is easy to cause the damage of facsimile machine Switching Power Supply.This novel buck AC voltage-stabilizing circuit has not only compared with prior art that volume is little, in light weight, efficient is high, cost is low, makes simply, and does not have the remarkable advantage that high order harmonic component is disturbed, but also has the start soft start function.Therefore this machine can ensure facsimile machine AC network up to 270 volts undesired high pressure under frequently start work and being without prejudice.4. designed the particular telephone circuit delay control circuit of forming by single-chip microcomputer IG1 triode V2, relay J 1 etc.Its effect is when single-chip microcomputer receives the outside line bell signal, starting the AC power control circuit immediately in the facsimile machine power supply, cuts off getting in touch of telephone wire and facsimile machine circuit; Delay time after 2 seconds, again phone and facsimile machine line inlet are connected.To prevent that when just opening the facsimile machine power supply, the facsimile machine line inlet also receives the outside line bell signal.When circuit such as single chip microcomputer in the facsimile machine do not reach normal steady-working state as yet and just receive the ring triggering signal, can make the single-chip microcomputer order that makes a mistake, thereby cause the failure of automatic reception fax.

Embodiment below in conjunction with accompanying drawing carries out the more description of detail to the present invention.

Fig. 1 is an electric theory diagram of the present utility model.

Fig. 2～Fig. 3 is the physical circuit figure of each element circuit of the utility model.

The utility model mainly is to adopt new single chip microcomputer AT89C2051 to detect outside line bell signal and off hook signal as master controller, and control AC power output circuit and telephone signal input circuit are realized.It is made up of following 11 partial circuits.(A) is AC power input protection and low-voltage dc circuit among the figure as shown in Figure 1; (B) be AC power output soft start and overpressure protection circuit; (C) be ac output voltage/frequency-conversion circuit; (D) being single chip circuit, (E) is ring detecting circuit, (F) is antitheft circuit; (G) be telephone line interface circuit; (H) being facsimile machine off-hook detection circuit, (I) being the telephone line delay control circuit, (J) is telephone set off-hook detection circuit.

Be the principle that example elaborates the utility model each several part circuit with accompanying drawing 2～3 below, constitute and function.

A, AC power input protection and low-voltage dc circuit: by lightning prevention circuit, the suspension low-voltage dc circuit, zero passage sample circuit and 5 volts of voltage stabilizing circuit 4 parts are formed.Wherein C1, C2, LF1 and piezo-resistance VR1, VR2 form anti-lightning strike protective circuit; power transformer T1 level N2 and bridge rectifier BD2, C5, R3 form the low-voltage dc circuit with the ground insulation; T1 level N3; bridge rectifier BD1 and R2, D2 form the AC power supply zero point sample circuit, and integrated regulator 7805 (IC3) is formed the 5V voltage stabilizing circuit with D3, C3, C4.

B, AC power output soft start and overpressure protection circuit: form the output soft starting circuit by field effect transistor MT12N90 (V1), D4, R5, R6 and rectifier BD3; by single chip computer AT 89C2051 (IC1); optocoupler 4n25 (IC4), V1, BD3 form the overpressure protection circuit.

C, ac output voltage/frequency-conversion circuit: form by sampling transformer T2, bridge rectifier BD4, R7～R13, C7～C10 and voltage/frequency conversion integrated circuit LM331 (IC5) etc.

D, single chip circuit: comprise the single chip circuit that single chip microcomputer AT89C2051 (IC1) and R14～R18, C11～C18, crystal, D6 form, by monostable trigger 74HC123 (IC2) and R19, C19, the watchdog microcontroller circuit of forming and the alternating current zero-detection circuit formed by operational amplifier in R14, R15, D6 and the single-chip microcomputer.

E, ring detecting circuit are by the amplifier (IC6b) of dual operational amplifier LM358 and D7, D8, R20～R23, formations such as C21.

F, anti-theft wire circuit: robber's line detection circuit of forming by R24, R25, D9, C22 and operational amplifier IC6a and by triode 2N5551 (V3), D10, R26 form wire robber's interfered circuit two parts are constituted.

G, telephone line interface circuit are formed the telephone wire polarity transformation circuits and are formed lightning prevention circuit two parts by discharge diode VR3 and constitute by bridge rectifier BD5.

H, facsimile machine off-hook detection circuit: form by photoelectrical coupler IC7 (PC817) and BD6, R27, R28, C24, C25.

I, telephone line delay control circuit: by triode V2, relay J 1, R3, D11 form.

J, telephone set off-hook detection circuit: form by photoelectrical coupler PC817 (IC8) and BD7, R29, R30, C26.

Groundwork principle of the present utility model is summarized as follows:

At first the localpower input should be inserted 220 volts of AC power, telephone line P1 telephone socket; The input of facsimile machine power supply meets localpower output B, C and its mains switch is beaten to opening the position always; The input of facsimile machine telephone line links with this machine P2 socket; The input of telephone set telephone wire links with this machine P3 socket.At this moment localpower indicator light D1 is bright, expression is working properly.

1, when waiting state, the 48V direct voltage that BD5 sends into telephone line carries out reversal to be become+and 48V voltage is added on R20, D7, the R21 series circuit; But,, then export high level by voltage comparator (7) pin that operational amplifier IC6b forms so R21 goes up no-voltage because the puncture voltage of voltage stabilizing didoe D7 is 75V.When fax will be sent, at first the bell signal of 25HZ is sent in outside line, this bell signal becomes dc pulse voltage greater than 100V through the BD5 rectification, D7 is punctured, make (6) pin of IC6b obtain pulse input voltage, at this moment the just P3.0 mouth of output low level pulse-triggered single-chip microcomputer (IC9) of IB6b (7) pin greater than 2.5V.

When 2, single-chip microcomputer detected the P3.0 mouth low level pulse is arranged, just judging had the facsimile signal input, so carry out the program of receiving faxes.At first the P1.3 mouth is become low level output by high level, make photoelectrical coupler IC4 conducting.At this moment T1 level of power transformer V2 output is 11V to form tens volts direct voltage with alternating voltage geographical edge after BD2 rectification, C5 filtering, the triode in R4, IC4 makes the V1 saturation conduction to the grid of V～metal-oxide-semiconductor field effect transistor V1; Thereby 220 volts AC power just through BD3, V1, R6 to C, the alternating voltage through 2 of B, C add to 220 volts of facsimile machines is started working facsimile machine automatically.

3, at single-chip microcomputer the P3.0 mouth is become the low level while by high level, also the P1.7 mouth is exported by the low flat high level that becomes, the base stage that this high level adds to triode through R31 makes that V2 is full to close conducting, thereby makes relay J 1 action, with outer phone circuit and the disconnection of facsimile machine telephone line.Delay time after 2 seconds, P1.7 mouth output low level, V2 is ended, J1 discharges, and outer phone circuit and facsimile machine circuit reclose.The effect of this delay circuit is to prevent that facsimile machine from just having powered up the time that does not enter normal operating conditions as yet and just having received the outside line bell signal, thereby causes the facsimile machine misoperation.

4, after facsimile machine powered up for 2 seconds, the fax self-contained circuit all enters normal operating conditions, at this moment the outside line ringing voltage enters the facsimile machine line inlet through BD6, C25, R27, relay J 1 contact, skewer seat P2, electric circuit inspection promptly goes to the state of receiving faxes (in the special line facsimile machine, generally all be arranged on first ring then change fax) behind the bell signal in the facsimile machine.At first facsimile machine simulation off-hook is connected telephone line; Send the CED answer signal to the other side then, both sides enter the fax sending and receiving state like this.

5, behind facsimile machine simulation off-hook, telephone line has direct current to pass through, and (4) pin of photoelectrical coupler IC7 becomes low level; And add to single-chip microcomputer P3.2 mouth.The touring always incoming level that detects the P3.2 mouth of single-chip microcomputer, receiving faxes when this facsimile machine finishes after the simulation on-hook, and at this moment (4) pin of IG7 becomes the high level single-chip microcomputer to detect the P3.2 mouth is high level, promptly carries out time delay subroutine.Delaying time makes P1.3 mouth output high level after 1 minute, photoelectrical coupler IC4 ends; Field effect transistor V1 non-grid voltage ends immediately; Thereby turn-offed the output of 220 volts of alternating voltages, made the fax auto-shut-off.The effect of above-mentioned 1 minute time delay subroutine is: the facsimile machine that the has data of receiving faxes are very fast, and print slowlyer, and after data finished on-hook if facsimile machine is received faxes, this machine promptly turn-offed its AC power, might produce the problem that printing does not finish; And be provided with 1 minute power supply program of time-delay, can guarantee facsimile machine circuit simulation on-hook outside after, still can operate as normal 1 minute to finish that storage is printed or work such as printing facsimile report.

Two, to outgoing faxes

If 1 this facsimile machine has telephone bandset, after then picking up mobile phone, telephone line connects, outside line is powered to the facsimile machine mobile phone by light-emitting diode (i.e. 1,2 pin) and relay J 1 back contact in BD6, the R27IC7, at this moment (4) pin of photoelectrical coupler IC7 becomes low level, the P3.2 mouth that triggers single-chip microcomputer (IC1) makes it enter external interrupt, and single-chip microcomputer IC1 promptly carries out the start subprogram of sending a fax.At first P1.3 mouth output low level drives photoelectrical coupler IC4 and makes the field effect transistor conducting, and 220 volts of alternating currents are powered to facsimile machine through BD3, V1.At this moment facsimile machine just can by the key of sending a fax, change facsimile circuit with telephone line behind connection the other side to outward dialing, and mobile phone circuit is disconnected, and puts down the mobile phone on-hook then.After distributing fax, facsimile machine simulation on-hook, (4) pin of photoelectrical coupler IC7 becomes high level.It is high level that single-chip microcomputer IC1 detects the P3.2 mouth, delays time and after 1 minute the P1.3 mouth is exported high level, turn-offs the facsimile machine power supply.Time-delay in this 1 minute is so that facsimile machine distributes the usefulness of fax back print job report.

If 2 facsimile machines do not carry telephone bandset, can be with 1 dozen of extremely logical position of K switch of single-chip microcomputer P3.3 mouth, at this moment P3.3 mouth input low level enters external interrupt, duplicates the subprogram of starting shooting just carry out.This machine is powered to facsimile machine, the facsimile machine start; Can send a fax then finishes, and K1 is turn-offed, promptly turn-offed the facsimile machine power supply.

Three, duplicate

When using the facsimile machine photocopying materials, the duplicating switch K1 that connects single-chip microcomputer IC1, P3.3 mouth is beaten to logical position, single-chip microcomputer is just carried out and is duplicated the start subprogram.Be P1.3 mouth output low level, drive IC 4, V1 conducting are sent 220 volts of AC power to facsimile machine; Facsimile machine gets final product photocopying materials.After duplicating finishes, duplicating switch K1 is beaten to disconnected position, single-chip microcomputer P1.3 mouth output high level has promptly turn-offed the facsimile machine power supply.

Four, anti-lightning strike protection

This machine is provided with the anti-lightning strike protective circuit of being made up of C1, C2, LF1, VR1 in the AC power input, also is provided with the lightning prevention circuit that C6, VR2 form in AC power output.The puncture voltage of piezo-resistance VR1, VR2 is 470V, and the momentary pulse electric current is up to 5KA; When the thunder and lightning high pressure entered AC power, this protective circuit just can be with the lightning voltage clamper about 470 volts.And this machine BD3, the permission of field effect transistor V1 and facsimile machine Switching Power Supply is withstand voltage all greater than 600 volts; Therefore this protective circuit can prevent that this machine and facsimile machine from being damaged by the thunder and lightning of introducing from AC power.Be provided with discharge diode (VR3) lightning prevention circuit in the telephone wire porch with sample machine, about 200 volts punctures of this discharge diode, permission puncture pulse current 10KA; And interior telephone line of facsimile machine and this electromechanics words circuit allow withstand voltage also greater than 200 volts; Therefore, this lightning prevention circuit can guarantee that this machine and facsimile machine are not damaged by the thunder and lightning high pressure of introducing from telephone wire.

Five, facsimile machine start soft start and overpressure protection circuit

1, start soft start

Switching Power Supply input high direct voltage filter capacitor capacity is bigger in the facsimile machine, so facsimile machine power supply start moment can produce the big electric current of very big high voltage surge.If not to the big electric current restriction of this high voltage surge, it is more to receive number of times at fax, and during to fax power supply frequent switch, facsimile machine inner high voltage filter capacitor and other relevant device will damage because of being subjected to the frequent start high pressure that produces import big surge rush of current, thereby cause facsimile machine to damage.

The preventing of this machine design surge current of starting shooting is that the soft starting circuit principle is: when single-chip microcomputer P1.3 mouth output low level, when driving photoelectrical coupler IC4 (5) (4) pin conducting; The alternating voltage that T1 level of power transformer N2 produces is through the BD2 rectification, form the direct voltage of about 13～14V after the C5 filtering, add to power field effect pipe V1 grid, the two poles of the earth, source because 10V voltage stabilizing didoe D4 clamper through R4, IC4, voltage 10V only between R6～V1 grid; Again because make the gate source voltage of V1 saturation conduction must be greater than 4V, so R4 promptly becomes the current-limiting resistance of V1 saturation conduction; When V1 source resistance R6 value was 2 Ω, then the maximum saturation electric current of V1 was only about 3 amperes.Because the 220V line voltage adds to the facsimile machine Switching Power Supply through bridge rectifier BD3 and V1, R6 series connection, therefore when the moment to the facsimile machine power supply, although its Switching Power Supply inner high voltage filter capacitor charging resistor is very little; But because the restriction of field effect transistor V1 maximum saturation electric current, can be to the maximum charge stream of high-voltage capacitance greater than 3A yet, this is a safe current for facsimile machine Switching Power Supply input circuit.In the moment to fax start, because the metering function of V1,220 volts high pressure mainly falls on V1 like this, and what add to the Switching Power Supply input circuit is the low voltage safety electric current.Along with Switching Power Supply high-voltage capacitor charging electric current reduces gradually, charging voltage increases gradually, after the charging interval, field effect transistor V1 conduction voltage drop is normal value (less than 2V) at process 5RC; And 220 volts of ac output voltages are all supplied with the facsimile machine Switching Power Supply basically.

Owing to 5RC charge constant value number less (less than 1 second), therefore can not influence the speed of facsimile machine start work.Although and the high power consumption that field effect transistor V1 is bearing V3A more than 300 in start moment; But because the time is very short, the selected field effect transistor permission of this machine operating current reaches 10A in addition, operating voltage reaches 900V, and the design surplus capacity is bigger, is very safe therefore.

This mode of taking low-voltage, safe current to start to facsimile machine start power supply moment promptly is referred to as to call soft start, and this soft start function of this machine can be guaranteed to fax frequent start and can not damage.

2, overpressure protection circuit

Switching Power Supply allows input ac voltage mostly between 160V～240V in the general facsimile machine, and when alternating voltage during greater than 230V, facsimile machine is operated near the limiting value.Because power load is lighter, add three-phase electricity consumption imbalance at night, a lot of local night line voltage greater than 230 volts, have in addition lie prostrate up to more than 250, this has surpassed facsimile machine Switching Power Supply limiting value for operation; Especially under summer high temperature environment, make the work of facsimile machine superpressure again, then easily cause damage.

For this this machine has designed the overpressure protection circuit, its operation principle is: (1) voltage/frequency conversion.When to facsimile machine power supply 220V, exchange output sampling transformer T2 secondary voltage through the BD4 rectification, form the direct voltage of 4V after C7, R8, the C8 filtering, promptly sampling voltage is added to voltage/frequency conversion integrated circuit LM331 (IC5) 7 pin.LM331 is an analog to digital converter with high accuracy, wide temperature range, cheapness, and its output frequency strictly is proportional to input direct voltage.Therefore this voltage/frequency converter is aligned when 7 pin input voltage 4V, its (2) pin output frequency is 4KHZ; When the alternating voltage that adds to facsimile machine was 225V, the sampling direct voltage was input as 4.091V, and the IC5 output frequency is 4.091KHZ; By that analogy, when alternating voltage was 260V, the sampling direct voltage was output as 4.727V, and then the IC5 output frequency is 4.727KHZ.The P3.4 mouth that the output frequency of IC5 is added to single-chip microcomputer IC1 is the T0 mouth, and single-chip microcomputer is started shooting the subprogram establishment for when the T0 mouth detects incoming frequency greater than 4.091KHZ, promptly carries out the lowering and stabilizing blood pressure levelling.(3) lowering and stabilizing blood pressure adjustment.Ac grid voltage forms the 10ms width after BD3 reversal half cycles pulse voltage is added to the source-drain electrode of field effect transistor V1, if the V1 saturation conduction, then the voltage through BD3, V1 output is still 50HZ pure sine wave voltage; If V1 has several not conductings of half cycles in each second, then output voltage becomes discontinuous sine voltage of certain time.Because the alternating current of 50HZ has several half cycles to disappear, naturally its voltage effective value will fall at the end; If by the number of voltage sampling feedback regulation 50HZ AC power output half cycles, then this step-down levelling just can make output voltage stabilization in a certain range of set value.If field effect transistor V1 conducting, the time that ends just in time are on AC power supply zero point, then adjust the AC power of positive back output, still can be the pure sine wave alternating current of 50HZ, disturb without any high order harmonic component.

This machine decompression voltage regulator is promptly according to above-mentioned principle design.At first IC1 obtains the pulse at zero point by zero-detection circuit, and zero-detection circuit is made up of P1.0, P1.1 mouth operational amplifier etc. among T1 level of power transformer N3, BD1, D2, R2, R14, R15, D6, the IC1.BD1 becomes the 8.5V alternating voltage of T1N3 into the 10ms pulsating direct current, inputs to the P1.1 mouth of IC1 via R2, and the P1.0 mouth of IC1 is obtained the voltage of IV by divider resistance R14, R15, and this voltage is compared with the pulsating voltage of P1.1 mouth.When at AC power supply zero point, the pulsating voltage of P1.1 mouth is lower than P1.0 mouth voltage, IC1 internal arithmetic amplifier output high level; When alternating current during not at zero point, the voltage of P1.1 mouth is all greater than p1.0 mouth voltage, operational amplifier output low level then in the IC1; Therefore the high level of operational amplifier output in the IC1 promptly is the AC power supply zero point pulse.Wherein the effect of D6 is the input voltage clamper with the P1.1 mouth, in case overtension damages the P1.1 mouth; The effect of D2 is to cut off the filtering of C3 to the 10ms pulse voltage of BD1 output.

When single-chip microcomputer IC1 detects incoming frequency greater than 4.091KHZ from the T0 mouth, just carry out the pressure regulation subprogram.When IC1 detects the AC power supply zero point pulse, just, make not conducting of photoelectrical coupler IC4 with P1.3 mouth output high level, field effect transistor V1 turn-offs.Simultaneously, should turn-off what 10ms each second according to the frequency computation part of T0 mouth input, so that the effective value of output AC voltage is reduced to about 220 volts; And according to time of this result of calculation decision P1.3 mouth output high level.The result of this levelling simultaneously feeds back to single-chip microcomputer T0 mouth through exchanging output sampling transformer T2 and voltage/frequency converter LM331 (IC5) in frequency height mode again; Single-chip microcomputer is promptly aligned error according to this feedback frequency correction, thereby has guaranteed the accuracy of this machine output voltage step-down levelling.

Several half cycles of this minimizing 50HZ AC power of the present invention reach alternating voltage and surpass 225 volts stable modes of aligning about 220 volts when above, are well suited for the machine of application switch power supply; As facsimile machine, computer etc.; Because its Switching Power Supply itself possesses the low-voltage voltage stabilizing output function between 160～220 volts.Promptly begin the design of voltage stabilizing just because of Switching Power Supply is this from low supply voltage very, just caused greater than 220 volts of voltages the time, the injectron angle of flow is very little, switching loss strengthens because the result of its voltage stabilizing levelling makes; Especially under too high voltages, easily cause injectron to puncture, design high drops so this machine does not design the low pressure voltage stabilizing and press voltage stabilizing just to have than significant protective effect.

Six, telephony feature

This machine can add a phone, and telephone set telephone line interface and this machine P3 interface are connect.When picking up mobile phone, just connected outer telephone wire.The off-hook detection circuit output low level of being made up of BD7, R29, C26, R30, photoelectrical coupler IC8 simultaneously adds to the P1.5 mouth of single-chip microcomputer IC1 through IC8 (5) pin, and single-chip microcomputer just seals rope P1.4 mouth after detecting this low level.Make it not produce interference to outside line.

Seven, anti-theft wire function

At normal hook state, outer telephone wire direct voltage is 48V; Add to R24 through BD5, the 48V voltage of D9, R25 punctures the latent diode D9 that presses of 15V, and the voltage drop that makes R25 greater than operational amplifier LM358 (IC6a) (2) pin voltage, makes IC6a (1) pin output high level about 4V.

At this machine outside line extension telephone machine, when usurping telephone wire and making a phone call, outer line drop is to 10V as the people.Therefore voltage stabilizing didoe D9 can not puncture, and the voltage on the R25 is 0V, thereby makes IC6a (1) pin output low level trigger single-chip microcomputer.Single-chip microcomputer IC1 just carries out interference outside line subprogram after the P3.7 mouth detects this low level, it is P1.4 mouth output 1KHZ disturbing pulse, adding to triode V3 by R26 amplifies, output in the outside line to disturb through BD5 and steal the line phone and make its no normal dialing output, glittering the sending warning signal of while light-emitting diodes D10.After having only the on-hook of the line of robber telephone set, because outside line voltage returns to 48V, operational amplifier IC6a (1) pin output high level, single-chip microcomputer just stop to disturb.

Claims (6)

1. intelligent facsimile motor protector, it is characterized in that control circuit is that core constitutes with single chip circuit (D), its output of AC power input protection and low-voltage dc circuit (A) input termination civil power connects single chip circuit (D) and AC power output soft start and overpressure protection circuit (B), and the output of AC power output soft start and overpressure protection circuit (B) connects ac output voltage/frequency-conversion circuit (C) and facsimile machine power circuit; The output order sheet machine circuit (D) of ac output voltage/frequency-conversion circuit (C); Telephone wire is connected to single chip circuit (D) by telephone line interface circuit (G), ring detecting circuit (E), and telephone line interface circuit (G) also is connected with telephone line circuitry (F), facsimile machine off-hook detection circuit (H), telephone set off-hook detection circuit (J) with antitheft; Facsimile machine off-hook detection circuit (H) links to each other with telephone wire by delay control circuit (I), and delay control circuit (I) control end connects single chip circuit (D); Telephone set off-hook detection circuit (J) also links to each other with single chip circuit (D) with telephone wire; Antitheft output with telephone line circuitry (F) links to each other with single chip circuit (D).

2. intelligent facsimile motor protector as claimed in claim 1 is characterized in that the alternating current zero-detection circuit that described single chip circuit (D) comprises host scm integrated circuit (IC1), formed anti-jamming circuit and be made up of operational amplifier in resistance (R14, R15), diode (D6) and the single-chip microcomputer by monostable trigger (IC2).

3. intelligent facsimile motor protector as claimed in claim 1; it is characterized in that described AC power input protection and low-voltage dc circuit (A) comprise capacitor (C1; C2); the anti-lightning strike protective circuit that inductance (LF1) and piezo-resistance (VR1) are formed; transformer (T1) secondary (N2) and rectifier (BD2); capacitor (C5); resistor (R3) that form with the low-voltage dc circuit ground insulation, transformer (TI) secondary (N3); rectifier (BD1); resistor (R2); AC power zero crossing sample circuit and integrated regulator (IC3) and diode (D3) that diode (D2) is formed; capacitor (C3; C4) the 5V voltage stabilizing circuit of Zu Chenging.

4. the described intelligent facsimile motor protector of claim 1; it is characterized in that described AC power output soft start and overpressure protection electricity (B) and ac output voltage/frequency-conversion circuit (C); comprise by field effect transistor (V1); diode (D4); resistor (R5; R6); the output soft starting circuit that rectifier (BD3) is formed; by single-chip microcomputer (IC1), and photoelectrical coupler (IC4); field effect transistor (V1); the lowering and stabilizing blood pressure that rectifier (BD3) or solid-state relay are formed is adjusted circuit and by output voltage sampling transformer (T2); rectifier (BD4); output voltage/frequency-conversion circuit that V/F converter (IC5) is formed.

5. the described intelligent facsimile motor protector of claim 1; it is characterized in that described ring detects (E) and the antitheft telephone line circuitry (F) of using; comprise by rectifier (BD5); capacitor (C20); polarity switching and anti-lightning strike protective circuit that discharge diode (VR3) is formed; by operational amplifier (IC6b); diode (D7; D8); resistor (R20～R23); the ring detecting circuit that capacitor (C21) is formed is by operational amplifier (IC6a); diode (D9); resistor (R24); what capacitor (C2) was formed is antitheft with the phone line detection circuit with by triode (V3); resistor (R26); telephone circuit is usurped in the interference that diode (D10) and single-chip microcomputer (IC1) are formed.

6. the described intelligent facsimile motor protector of claim 1; it is characterized in that described off-hook detection (H, J) and delay control circuit (I); comprise the facsimile machine off-hook detection circuit of forming by rectifier (BD6), photoelectrical coupler (IC7) (H), telephone set off-hook detection circuit of forming by rectifier (BD7), photoelectrical coupler (IC8) (J) and the facsimile machine circuit delay control circuit of forming by triode (V2), diode (D11), relay (J1) (I).

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