DPC817 photosensitive resister

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DPC817 photosensitive resister

Mere coupler

Abbreviate as OC in English) Also call the photoelectric isolator or photoelectrical coupler, is abbreviated as the photosensitive resister. It regards light as media to transmit the device of the electric signal, usually a giving out light device (infrared ray LED LED) With receiving the mere device ' The photosensitive semiconductor is in charge of) Encapsulate in the same tube of shell. The giving out light device emits the light, produce the photocurrent after being accepted the light by the mere device when adding the electric signal in input terminus, flow out from output end, thus has realized " electricity - light - electricity " Conversion. Regard light as media to couple the input terminus signal to the photoelectrical coupler of the output end, because it is small, longe-lived, contactless, the ability to resist interference is strong, insulating while exporting and inputting, transmit advantages such as signals,etc. unidirectionally, find extensive application on the digital circuit.

Operation principle

The coupler regards light as media to transmit the electric signal. It has good segregation function on inputting, outputting the electric signal,
It become the intersection of kind and most many, the intersection of use and wide photoelectric device most one of already at present. The mere coupler is generally made up of three parts: Mere transmission, mere receiving and signal are amplified. The electric signal input drives LED (LED) ,Make it emit light of certain wavelength, is received and the photocurrent emerges by the mere detector, export after further enlarging. This finishes conversion of the electricity - light - electricity, thus play input, function outputted, isolated. Because the mere coupler inputs and exports one to isolate each other, electric signal transmission has characteristic such as being unidirectional, therefore have good electric insulating capacity and ability to resist interference. Because mere input terminus of coupler whom electric current type work low to hinder the component again, therefore have the very strong one altogether the mould inhibits ability. So it in long-line to transmit in the information as can improve SNR greatly while being terminal to isolate the component. Interface device isolated in digital communication of computer and real-time control as the signal, can improve the dependability of the computer work greatly.

Advantage

The major advantage of the mere coupler is: The signal was transmitted unidirectionally, input terminus and output end have totally realized the electricity is isolated, it doesn't influence the input terminus to output signals, the ability to resist interference is strong, it is steady to work, contactless, have long performance life, it is high in efficiency to transmit. The mere coupler developed and produced the new device in the seventies, it is electric and insulating to already used in extensively now, level is changed, interstage coupling, drive the circuit, switch circuit, chopper, how the oscillator, signal in harmony are isolated, isolating, pulse amplifies circuit, digital instrument, remote signal transmission, pulse amplifying, solid relay (SSR) among grade , in the instrument and apparatus, communication equipment and computer interface. In the switch power of one piece, utilizing the linear mere coupler forms feedback circuit of photosensitive resister, it change by regulating the electric current of control end it it is be empty to take than,more accurate by steady voltage purpose when achieving.

The photoelectrical coupler is divided into two kinds: One non-linear photosensitive resister, another kind of the linear photosensitive resister.
Because of a very large number of breeds and types of the photoelectrical coupler, in the photoelectron DATA manual, its type exceeds thousands of kinds, can usually classify according to the following methods:

According to mere route, can be divided into a mere way photoelectrical coupler (also called the measuring device intermittently of photoelectricity) outside With the inner mere way photoelectrical coupler. Outside it is mere way for photoelectrical coupler divide into again through type and reflecting photoelectrical coupler.

Divide according to outputting the form, can be divided into:

A, photosensitive device exporting type, include the exporting type of the photodiode, photosensitive triode exporting type, photocell exporting type, mere silicon controlled rectifier exporting type,etc..

B, NPN triode exporting type, includes the input exchanging type, the inputting type of direct current, complementary output type,etc..

C, Darington's triode exporting type, includes the input exchanging type, the inputting type of direct current.

D, logic gate circuit exporting type, include the circuit exporting type of the door, Schmitt touches off the exporting type, exporting type of a piece of circuit of three attitudes,etc..

E, low to lead the put through exporting type ' Output one millivolt of orders of magnitude of low level) .

F, smooth the switch exporting type ' Lead the open resistance Xiao Yu 10ж╕) .

G, power output? ? ? (IGBT/MOSFET,etc. exports) .

Divide according to transmitting signals, can be divided into a digital photoelectrical coupler (OC door exporting type, the intersection of totem and person who export and ternary the intersection of door and the intersection of circuit and person who export,etc.) With the linear photoelectrical coupler (can be divided into a low drifting about type, the high linearity type, broadband type, single power type, one pair of power types,etc.) .

According to speed, can be divided into a low-speed photoelectrical coupler (exporting types such as photosensitive triode, photocell,etc.) With the high-speed photoelectrical coupler ' The photodiode takes signals to deal with circuit or photosensitive integrated circuit exporting type) .

According to passway, can be divided into single passway, one pair of passways and many passway photoelectrical couplers.

Divide according to isolating the characteristic, can be divided into and isolated the photoelectrical coupler (general optical glue is encapsulated and lower than 5000V ordinarily, it is sealed and is lower than 2000V that empty) With isolating the photoelectrical coupler (can be divided into 10kV, 20kV, 30kV,etc.) under high pressure .

According to working voltage, can be divided into a low power voltage type photoelectrical coupler (general 5- 15V) With the high power voltage type photoelectrical coupler ' Generally greater than 30V) .

1.It inputs to be and insulating between the output end, its insulating resistance is generally greater than 10000Mж╕, able to bear can generally exceed 1kV to press, some can even reach above 10kV.

2.Because the mere receiver can only accept the message of the light source, can't on the contrary, the signal is unidirectional from the light source will not feedback the phenomenon while transmitting to the mere receiver, it will not influence the input terminus either while outputting signals.

3.Because of give out light device ' Infrared diode of GaAs) It is a impedance electric current driving device, and the noise is that one kind hinders the little electric current voltage signal inside high. So photoelectricity couple device mould inhibit than very heavy, so photoelectricity couple the device may well inhibit the interference from and dispel the noise altogether.

4.It is easy and the logical circuit cooperates.

5.The response speed is fast. Photoelectricity couple time of device constant even millimicrosecond extremely in microsecond usually.

6.Contactless, longe-lived, small, shock-resistant.

Performance characteristic

The major advantage of the mere coupler is to transmit signals unidirectionally, input terminus and output end have totally realized the electricity is isolated, the ability to resist interference is strong, have long performance life, it is high in efficiency to transmit. It is used in level changing, signal isolating, isolating, switch circuit, remote signal transmission, pulse amplifying, solid relay (SSR) among grade extensively , in the instrument and apparatus, communication equipment and computer interface. Because the input impedance of the photoelectrical coupler, with generally interfering with the impedance of the source to compare low, so partial pressure is relatively small in the interference voltage of the input terminus of the photoelectrical coupler, the electric current and big that it can offer, it is difficult to make the semi-conductive diode give out light; Because the outer cover of the photoelectrical coupler is sealed, it is free of external light; The segregation of the photoelectrical coupler is very large in resistance ' About 1012ж╕) , isolate very much little electric capacity ' About several pFs) So can prevent the circuit from coupling the electromagnetism produced to interfere with. The photoelectrical coupler that the linear way works adds and controls the voltage in the input terminus of the photoelectrical coupler, will produce the voltage of a piece of circuit used for further controlling the next grade in the output end proportionally. The linear photoelectrical coupler is made up of LED and photosensitive triode, put through and give out light in LED, the photosensitive triode is led openly, the photoelectrical coupler is the driving type of the electric current, needing electric current large enough make LED lead openly, if the input signal is too small, LED will not be led openly, it will be distorted that it outputs signals. Among power of switch, especially power of digital switch, utilizing the linear mere coupler forms feedback circuit of photosensitive resister, it it changes by regulating the electric current of control end that it is be empty to take than,achieve more accurate by steady voltage purpose.

The technical parameter of the mere coupler mainly has LED to press and lower VF forward, the forward electric current IF, electric current transmit than CTR, input grade and insulating resistance, collector - emitter that output among grade and punctures voltage V (BR) backward CEO, collector - emitter saturate and press and lower VCE (sat) . In addition, also need parameter of considering the time of rising, dropping time, delaying time and storing time etc. while transmitting the digital signal.

Electric current transmit than mere important parameter of coupler, spread, fail, express come oning with direct current usually. When the output voltage keeps invariable, it means direct current outputs electric current IC and direct current and inputs the percentage of the electric current IF. Adopt the mere coupler of a photosensitive triode, ranges of CTR are mostly 20%- 300% (such as 4N35) ,But PC817 is 80%- 160%, Darington type mere coupler (such as 4N30) Can be up to 100%- 5000%. This indicates to want to obtain the same output electric current, the latter only needs the electric current of smaller input. So, CTR ginseng? ? ? Have a certain similarity with hFE of the transistor. Linear mere coupler and typical CTR-IF characteristic curve of ordinary mere coupler.

CTR-IF characteristic curve of the ordinary mere coupler is non-linear, the nonlinearity when IF is smaller is distorted and particularly serious, so it is unsuitable to transmit the analog signal. CTR-IF characteristic curve of the linear mere coupler has good linearity degree, especially while transmitting the little signal, its exchange electric current transmission than ( жд CTR =жд IC / жд IF) It is more worthier than CTR to approach the direct current and spread and fail very much. So it suitable for transmit the intersection of simulation and voltage or the intersection of electric current and signal, can make output and input into, presenting the linear relation. This is its important characteristic.

Technical parameter

The technical parameter of the mere coupler mainly has LED to press and lower VF forward, the forward electric current IF, electric current transmit than CTR, input grade and insulating resistance, collector - emitter that output among grade and punctures voltage V (BR) backward CEO, collector - emitter saturate and press and lower VCE (sat) . In addition, also need parameter of considering the time of rising, dropping time, delaying time and storing time etc. while transmitting the digital signal. Electric current transmit than mere important parameter of coupler, spread, fail, express come oning with direct current usually. When the output voltage keeps invariable, it means direct current outputs electric current IC and direct current and inputs the percentage of the electric current IF. Using the photoelectrical coupler is mainly for offering the circuit of input and exporting the segregation among the circuit, while designing the circuit, must follow the following principles: The photoelectricity selected for use must accord with the standard about isolating and puncturing the voltage of our country and world while coupling the device; By British Esso Curme (Isocom) 4N * which company, American Motorola Company produce *Series ( Such as 4N25, 4N26, 4N35) Mere coupler, it is very general to employ the ground at home. Seeing that this kind of mere coupler presents the switch characteristic, its degree of linearity is poor, suitable for transmitting the digital signal (high, low level) ,The output that can be used in the one-chip computer is isolated; Photosensitive resister devices selected for use must have higher coupling coefficients.

Function of the products

Play a isolating role in inputting, outputting the electric signal, the mere coupler is generally made up of three parts: Mere transmission, mere receiving and signal are amplified. The electric signal drives LED (LED) ,Make it emit light of certain wavelength, is received and the photocurrent emerges by the mere detector, export after further enlarging. This finishes conversion of the electricity - light - electricity, thus play input, function outputted, isolated. Because the mere coupler inputs and exports one to isolate each other, electric signal transmission has characteristic such as being unidirectional, therefore have good electric insulating capacity and ability to resist interference. Because mere input terminus of coupler whom electric current type work low to hinder the component again, therefore have the very strong one altogether the mould inhibits ability.

Using priciple

1,Mere electric current of coupler transmit than (CTR) Permission range 50%-200%. This is because act as CTR

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