CN202550878U

CN202550878U - DC voltage accurate isolator based on common optical coupler

Info

Publication number: CN202550878U
Application number: CN2012200780137U
Authority: CN
Inventors: 薛晓明; 陈震; 刘庆新
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-02-27
Filing date: 2012-02-27
Publication date: 2012-11-21
Anticipated expiration: 2022-02-27

Abstract

The utility model discloses a DC voltage accurate isolator based on a common optical coupler, comprising an input circuit, a common optical coupler, and an output circuit, wherein the input circuit is connected with an exerted DC voltage Vi, the transmitting end of the common optical coupler is connected with the input circuit, the receiving end of the common optical coupler is connected with the output circuit, and the output circuit outputs an isolated DC voltage signal Vo. In the process of using, an externally-exerted DC adjustable voltage Vi is transmitted to the current limiting resistor end by a certain distance, an electrolytic capacitor connected across both ends of the optical coupler can filter various high frequency interferences in the process of transmitting the DC adjustable voltage, then the filtered DC voltage signal is transmitted to a light emitting diode at the transmitting end of the optical coupler to enable the light emitting diode to emit light, and a phototriode at the receiving end of the optical coupler receives light, generates an amplified current, and outputs an isolated DC voltage signal through filtering various interference through an adjustable T-type filtering network in the output circuit. The DC voltage accurate isolator based on a common optical coupler can accurately isolate and output a DC voltage changing with an input voltage according to a same ratio no matter what the parameters of the optical coupler are, dispenses with using an isolation power supply and a single-chip microcomputer for digital analog conversion at an input end, and has the characteristics of being simple in circuit, low in cost, and accurate in DC voltage output.

Description

Based on the accurate isolator of the direct voltage of common optocoupler

Technical field

The utility model relates to the accurate isolator of a kind of direct voltage based on common optocoupler, particularly relates to a kind ofly using common optocoupler and precisely isolating and transmit the device of power supply machine speed governing with d. c. voltage signal.

Background technology

In the speed regulating control of motor; At present all be to convert the switch that pwm signal goes to control high power device to and realize that for ease to the control of speed governing, the circuit of regulating direct voltage usually is what to separate with master control borad through direct voltage being sent to master control borad; Caused direct voltage when being transferred to master control borad, to produce various interference; Influence the operate as normal of Electric Machine Control plate, even damage control board, cause serious consequence.Therefore, an isolation amplifier is arranged on the master control borad in actual use, promptly extraneous variable direct voltage is transferred to earlier on the isolator of control board, after isolator is isolated, is sent to master control borad again.In order correctly to reflect variable direct voltage, isolator must can be eliminated external interference, precisely follows input direct voltage by same ratio.Common light-coupled isolation is convenient, and cost is very low, but because the dispersiveness of different optocoupler current transfer ratios is bigger, same DC input voitage is very big through the direct voltage otherness of isolating back output, thereby the motor speed that causes controlling is inconsistent.In order to guarantee consistency; Usually adopt single-chip microcomputer to convert the direct voltage of input to PWM digital signal (abbreviation digital-to-analogue conversion) at present, after isolating through high speed photo coupling then, convert direct voltage again to; Deliver to master control borad; Not only cost is very high, complicated circuit, and also need use insulating power supply and single-chip microcomputer at input.

Summary of the invention

The utility model purpose is the deficiency to prior art, proposes a kind of device that common optocoupler is realized accurate isolated DC voltage of using.For achieving the above object, the design of the utility model is: the transmitting terminal through at common optocoupler adds electrochemical capacitor, adds that at the receiving terminal of common optocoupler adjustable T type network realizes.

The related principle of utilizing the accurate isolated DC voltage of common optocoupler of the utility model is described below.

As shown in Figure 1, according to the characteristics of common optocoupler, when the input current of optocoupler transmitting terminal light-emitting diode in the 1-10mA scope; The current transmission characteristic of optocoupler is linear, supposes that the electric current through different optocoupler light-emitting diodes all is IF1 when the maximum direct voltage of input, and 1# optocoupler current transfer ratio is K1; 2# optocoupler current transfer ratio is K2; For guaranteeing that two kinds of output dc voltages under the situation equate, shown in Fig. 2 (a) and (b), regulating the resistance of connecting with 1# optocoupler receiving terminal phototriode is RW1; Regulating the resistance of connecting with 2# optocoupler receiving terminal phototriode is RW2, then:

K1*RW1＝K2*RW2 (1)

When the feasible electric current through the optocoupler light-emitting diode of adjusting input direct voltage was IF2, the current transfer ratio of establishing 1# optocoupler this moment was K10, and the current transfer ratio of 2# optocoupler is K20, has:

K1/K10＝K2/K20 (2)

(1) formula substitution (2) formula can be obtained:

K10*RW1＝K20*RW2 (3)

Can find out from (3) formula; Through when importing maximum direct voltage, regulating the variable resistor that is connected on optocoupler transmitting terminal triode emitting stage; The output dc voltage that guarantees the different parameters optocoupler equates, all keeps the accurate control that equates thereby be implemented in the direct voltage that passes through any identical input voltage under after the different parameters light-coupled isolation.

According to above-mentioned design, the utility model adopts following technical proposals:

The accurate isolator of a kind of direct voltage based on common optocoupler; Comprise input circuit, common optocoupler, output circuit; Said common optocoupler comprises light-emitting diode that is positioned at transmitting terminal and the phototriode that is positioned at receiving terminal, and said input circuit is connected with the direct voltage Vi that applies, and the transmitting terminal of said common optocoupler is connected with input circuit; The receiving terminal of said common optocoupler is connected with output circuit, the d. c. voltage signal Vo after said output circuit output is isolated.

Described input circuit comprises current-limiting resistance R1, electrochemical capacitor C1; The left end of resistance R 1 is connected with the direct voltage anode Vi of outside input; The light-emitting diode anode tandem of the anode of the right-hand member of resistance R 1, electrochemical capacitor C1, common optocoupler transmitting terminal, the light-emitting diode negative terminal tandem of the negative terminal Vi of the lower end of electrochemical capacitor C1, input direct voltage, common optocoupler transmitting terminal.

Described common optocoupler comprises light-emitting diode that is positioned at transmitting terminal and the phototriode that is positioned at receiving terminal, and the collector electrode of phototriode is connected with DC power supply VCC.

Described output circuit comprises diode D1, resistance R 2 and R3, variable resistor RW, capacitor C 2 and C3; The negative terminal of diode D1 is connected with DC power supply VCC; The upper end of the upper end of the anode of diode D1, resistance R 2, the emitter of phototriode, capacitor C 2, the left end tandem of resistance R 3; The adjustable side tandem of the upper end of the lower end of resistance R 2, variable resistor RW, variable resistor RW; The lower end tandem ground connection of the lower end of variable resistor RW, capacitor C 2 and C3, the right-hand member of the upper end of capacitor C 3, resistance R 3 connect the d. c. voltage signal Vo after output is isolated.

Since at the two ends of common optocoupler transmitting terminal light-emitting diode parallel connection an electrochemical capacitor; Filtering the input the various High-frequency Interference of direct voltage in long-distance transmissions; Only let d. c. voltage signal pass through light-emitting diode, connected a T type adjustable network, the various High-frequency Interference of filtering again at the emitting stage of normal optical coupling receiving terminal phototriode; Guarantee when input direct voltage is identical, equal through the direct voltage of different qualities light-coupled isolation output.Therefore; The utility model is compared with background technology, no matter optocoupler parameter discrete type how, can both precisely be isolated output by same ratio and follow the direct voltage that input voltage changes; And need not to use insulating power supply and single-chip microcomputer to carry out digital-to-analogue conversion at input; It is simple to have circuit, with low cost, precisely the characteristics of output dc voltage.

Description of drawings

Fig. 1 is the common optocoupler transmission characteristic figure that the utility model is used.

Fig. 2 is that the different optocouplers of the utility model are regulated variable-resistance sketch map.

Fig. 3 is the block diagram of the utility model, among the figure: 1, input circuit, 2, common optocoupler, 3, output circuit.

Fig. 4 is the circuit connection diagram of an embodiment of the utility model.

Embodiment

Below in conjunction with accompanying drawing the utility model is further described.

As shown in Figure 3; The accurate isolator of a kind of direct voltage of the utility model based on common optocoupler; Comprise input circuit (1), common optocoupler (2), output circuit (3), input circuit (1) is connected with the direct voltage Vi that applies, and the transmitting terminal of common optocoupler (2) is connected with input circuit (1); The receiving terminal of common optocoupler (2) is connected with output circuit (3), the d. c. voltage signal Vo after output circuit (3) output is isolated.

As shown in Figure 4; Input circuit (1) comprises current-limiting resistance R1, electrochemical capacitor C1; The left end of resistance R 1 is connected with the direct voltage anode Vi of outside input; The light-emitting diode anode tandem of the anode of the right-hand member of resistance R 1, electrochemical capacitor C1, common optocoupler (2) transmitting terminal, the light-emitting diode negative terminal tandem of the negative terminal of the lower end of electrochemical capacitor C1, input direct voltage Vi, common optocoupler (2) transmitting terminal; Common optocoupler (2) comprises light-emitting diode that is arranged in the transmitting terminal loop and the phototriode that is arranged in the receiving terminal loop; The collector electrode of phototriode is connected with DC power supply VCC; Output circuit (3) comprises diode D1, resistance R 2 and R3, variable resistor RW, capacitor C 2 and C3; The negative terminal of diode D1 is connected with DC power supply VCC; The upper end of the upper end of the anode of diode D1, resistance R 2, the emitter of phototriode, capacitor C 2, the left end tandem of resistance R 3; The adjustable side tandem of the upper end of the lower end of resistance R 2, variable resistor RW, variable resistor RW, the lower end tandem ground connection of the lower end of variable resistor RW, capacitor C 2 and C3, the right-hand member of the upper end of capacitor C 3, resistance R 3 connects the d. c. voltage signal Vo after output is isolated.

The course of work of the utility model is:

The direct current adjustable voltage of external world's input is adjusted to maximum; Be sent to the high-precision collimation stream voltage isolation circuit current-limiting resistance end that any constitutes based on common optocoupler through certain distance; To guarantee the maximum current (be generally 10mA) of maximum input current less than common optocoupler retention wire property; Again through after the various High-frequency Interference in the electrochemical capacitor filtering direct voltage transmission course that is connected in parallel on the optocoupler two ends; The light-emitting diode of pressing signal to deliver to optocoupler clean direct current makes it luminous, and the phototriode of optocoupler produces amplified current after receiving illumination, delivers to adjustable T type network; Regulating its variable resistor makes the direct voltage of its any circuit output all equal the needed voltage of motor maximum speed; Just can realize after the adjustment completion: as long as the direct current of input equates all have equal direct voltage no matter the optocoupler parameter of forming circuit how, is exported.

Above-mentioned embodiment is used for explaining the utility model; Rather than the utility model limited; In the protection range of the spirit of the utility model and claim, any modification and change to the utility model is made all fall in the protection range of the utility model.

Claims

1. based on the accurate isolator of the direct voltage of common optocoupler; It is characterized in that: comprise input circuit (1), common optocoupler (2), output circuit (3); Said common optocoupler (2) comprises light-emitting diode that is positioned at transmitting terminal and the phototriode that is positioned at receiving terminal; Said input circuit (1) is connected with the direct voltage Vi that applies; The transmitting terminal of said common optocoupler (2) is connected with input circuit (1), and the receiving terminal of said common optocoupler (2) is connected with output circuit (3), the d. c. voltage signal Vo after said output circuit (3) output is isolated.

2. the accurate isolator of the direct voltage based on common optocoupler according to claim 1; It is characterized in that: described input circuit (1) comprises current-limiting resistance R1, electrochemical capacitor C1; The left end of resistance R 1 is connected with the outside direct voltage anode Vi that applies; The light-emitting diode anode tandem of the anode of the right-hand member of resistance R 1, electrochemical capacitor C1, common optocoupler (2) transmitting terminal, the light-emitting diode negative terminal tandem of the negative terminal Vi of the lower end of electrochemical capacitor C1, input direct voltage, common optocoupler (2) transmitting terminal.

3. the accurate isolator of the direct voltage based on common optocoupler according to claim 1 is characterized in that: the collector electrode of described common optocoupler (2) receiving terminal phototriode is connected with DC power supply VCC.

4. the accurate isolator of the direct voltage based on common optocoupler according to claim 1; It is characterized in that: described output circuit (3) comprises diode D1, resistance R 2 and R3, variable resistor RW, capacitor C 2 and C3; The negative terminal of diode D1 is connected with DC power supply VCC; The upper end of the upper end of the anode of diode D1, resistance R 2, the emitter of phototriode, capacitor C 2, the left end tandem of resistance R 3; The adjustable side tandem of the upper end of the lower end of resistance R 2, variable resistor RW, variable resistor RW; The lower end tandem ground connection of the lower end of variable resistor RW, capacitor C 2 and C3, the right-hand member of the upper end of capacitor C 3, resistance R 3 connects, the d. c. voltage signal Vo after output is isolated.