CN218243500U - Isolated signal input circuit - Google Patents
Isolated signal input circuit Download PDFInfo
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- CN218243500U CN218243500U CN202222111584.2U CN202222111584U CN218243500U CN 218243500 U CN218243500 U CN 218243500U CN 202222111584 U CN202222111584 U CN 202222111584U CN 218243500 U CN218243500 U CN 218243500U
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Abstract
The utility model discloses an isolated signal input circuit, including the coupling unit, the coupling unit includes Pin2 foot and Pin3 foot, wherein be connected with first resistance and second resistance on the Pin2 foot, the second resistance is connected with Pin3 foot, be connected with the opto-coupler unit between first resistance and the second resistance, the input of opto-coupler unit is connected with first electric capacity, the output of opto-coupler unit is connected with second NPN triode, the output of second NPN triode is connected with first NPN triode, first NPN triode and first resistance coupling, and first resistance with second NPN triode connect, first NPN triode is connected with the third resistance, overcurrent protection circuit is constituteed with first NPN triode to the third resistance, the opto-coupler unit still is connected with logic level unit. The third resistor is a current-limiting sampling resistor. The first capacitance is 0.01UF. The utility model discloses the interference killing feature is strong.
Description
Technical Field
The utility model relates to the technical field of circuits, specifically be an isolated signal input circuit.
Background
The optical coupler is also called as a photoelectric isolator or a photoelectric coupler, and is called as an optical coupler for short. The device is a device for transmitting electric signals by taking light as a medium, and usually a light emitter (an infrared Light Emitting Diode (LED)) and a light receiver (a photosensitive semiconductor tube and a photosensitive resistor) are packaged in the same tube shell. When the input end is electrified, the light emitter emits light, and the light receiver receives the light, then the light generates photocurrent which flows out from the output end, thereby realizing 'electro-optic-electrical' control. The photoelectric coupler using light as medium to couple the input signal to the output has the advantages of small size, long service life, no contact, strong anti-interference ability, insulation between output and input, unidirectional signal transmission, etc. and is widely used in digital circuit.
The signal interference resistance processing is widely applied to the inkjet printer industry at present, signal interference misoperation becomes a very important factor to be considered for the normal use of a printer, and most printers in the existing application field ignore environmental interference factors; according to the using environment of the current various types of signal control processing devices, the using environment of the board card needs to meet the requirement of normal and stable operation under the severe condition of strong interference; however, the existing method cannot meet the condition, and therefore, an isolated signal input circuit is provided, so that the printer can normally work under various severe environments. There is a need for a tamper resistant isolated signal input circuit.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing an isolated signal input circuit, the utility model discloses a peripheral hardware module spreads digital signal or analog signal into the input of linkage unit, and the input signal of peripheral hardware is converted into the light signal to the optical coupling unit in the linkage unit, further converts the light signal into the electric signal, and the electric signal direct input is given to host system at last, and host system makes functional operation according to the electric signal information that the optical coupling unit was given to come; the utility model has the characteristics of low cost, high accuracy, high real-time, possess small, longe-lived, contactless, the interference killing feature is strong, and is insulating between output and the input, advantages such as one-way transmission signal. So that the printer can work normally under various environments. Have the advantage that the interference killing feature is strong, the utility model discloses the practicality is strong.
The utility model discloses a realize like this:
an isolated signal input circuit comprises a connecting unit, wherein the connecting unit comprises a Pin2 Pin and a Pin3 Pin, a first resistor and a second resistor are connected to the Pin2 Pin, the second resistor is connected with the Pin3 Pin, an optocoupler unit is connected between the first resistor and the second resistor, the input end of the optocoupler unit is connected with a first capacitor, the output end of the optocoupler unit is connected with a second NPN triode, the output end of the second NPN triode is connected with a first NPN triode, the first NPN triode is connected with the first resistor, the first resistor is connected with the second NPN triode, the first NPN triode is connected with a third resistor, the third resistor and the first NPN triode form an overcurrent protection circuit, and the optocoupler unit is further connected with a logic level unit.
Further, the third resistor is a current-limiting sampling resistor.
Further, the first capacitance is 0.01UF, the first resistance is 4.7K, and the second resistance is 1K.
Furthermore, pin2 is used for signal output, pin3 is used for power supply, a peripheral module is connected with the input end of the connecting unit, and a main control module is connected with the output end of the connecting unit.
The utility model discloses a theory of operation: when the external module normally has no signal output, the power supply supplies power to the Pin2 of the connecting unit through the second resistor to be in a high level, meanwhile, the bias current is provided to the second NPN triode through the first resistor and the third resistor, the second NPN triode is conducted and the optocoupler is conducted, and the D6 light emitting diode in a logic level is lightened. The third resistor is a current-limiting resistor, when the current of the second NPN triode continues to increase, the voltage of the third resistor also increases, when the differential pressure at the two ends is 0.7V, the first NPN triode is conducted to pull down the base voltage of the second NPN triode, the second NPN triode is turned off when the differential pressure is lower than the starting voltage, the third current is reduced, the voltage drop is reduced, when the differential pressure is lower than 0.7V, the first NPN triode is turned off, the base voltage of the second NPN triode is restored to be high-level conduction, the purpose of dynamic current limiting is achieved, the function of current limiting protection is achieved, and the maximum current is set to be I =0.7V/R3;
when the peripheral module is provided with a signal, the connecting unit Pin2 outputs a low level, the second NPN triode has no bias current, the optical coupling unit is cut off, and two ends of D6 in the logic level are high levels, so that the anti-interference effect is achieved.
Compared with the prior art, the beneficial effects of the utility model are that: the peripheral module transmits digital signals or analog signals to the input end of the connecting unit, an optical coupling element unit in the connecting unit converts peripheral input signals into optical signals, the optical signals are further converted into electric signals, finally the electric signals are directly input to the main control module, and the main control module performs functional operation according to the electric signal information sent by the optical coupling unit; the utility model has the characteristics of low cost, high accuracy, high real-time, possess small, longe-lived, contactless, the interference killing feature is strong, and is insulating between output and the input, advantages such as one-way transmission signal. So that the printer can work normally under various environments. Have the advantage that the interference killing feature is strong, the utility model discloses the practicality is strong.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a circuit diagram of the present invention;
FIG. 2 is a circuit diagram of a plurality of peripheral modules according to the present invention;
fig. 3 is a block diagram of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings of the embodiments of the present invention are combined to clearly and completely describe the technical solutions of the embodiments of the present invention, and obviously, the described embodiments are some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention. Thus, the following detailed description of the embodiments of the present invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1-3, an isolated signal input circuit includes a connection unit, the connection unit includes a Pin2 Pin and a Pin3 Pin, wherein the Pin2 Pin is connected to a first resistor and a second resistor, the second resistor is connected to the Pin3 Pin, an optocoupler unit is connected between the first resistor and the second resistor, an input end of the optocoupler unit is connected to a first capacitor, an output end of the optocoupler unit is connected to a second NPN transistor, an output end of the second NPN transistor is connected to a first NPN transistor, the first NPN transistor is connected to the first resistor, the first resistor is connected to the second NPN transistor, the first NPN transistor is connected to a third resistor, the third resistor and the first NPN transistor form an overcurrent protection circuit, and the optocoupler unit is further connected to a logic level unit. The third resistor is a current-limiting sampling resistor.
In this embodiment, the first capacitor is 0.01UF, the first resistor is 4.7K, and the second resistor is 1K. The Pin2 is used for signal output, the Pin3 is used for power supply, the input end of the connecting unit is connected with a peripheral module, and the output end of the connecting unit is connected with a main control module.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (5)
1. An isolated signal input circuit, comprising: the overcurrent protection circuit comprises a connecting unit, wherein the connecting unit comprises a Pin2 Pin and a Pin3 Pin, a first resistor and a second resistor are connected to the Pin2 Pin, the second resistor is connected with the Pin3 Pin, an optocoupler unit is connected between the first resistor and the second resistor, a first capacitor is connected to the input end of the optocoupler unit, a second NPN triode is connected to the output end of the optocoupler unit, a first NPN triode is connected to the output end of the second NPN triode, the first NPN triode is connected with the first resistor, the first resistor is connected with the second NPN triode, the first NPN triode is connected with a third resistor, the third resistor and the first NPN triode form an overcurrent protection circuit, and the optocoupler unit is further connected with a logic level unit.
2. An isolated signal input circuit as claimed in claim 1, wherein said third resistor is a current limiting sampling resistor.
3. An isolated signal input circuit according to claim 1, wherein the first capacitance is 0.01UF.
4. An isolated signal input circuit as claimed in claim 1, wherein said first resistor is 4.7K and said second resistor is 1K.
5. The isolated signal input circuit of claim 1, wherein Pin2 is used for signal output, pin3 is used for power supply, a peripheral module is connected to the input end of the connection unit, and a main control module is connected to the output end of the connection unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222111584.2U CN218243500U (en) | 2022-08-11 | 2022-08-11 | Isolated signal input circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222111584.2U CN218243500U (en) | 2022-08-11 | 2022-08-11 | Isolated signal input circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218243500U true CN218243500U (en) | 2023-01-06 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222111584.2U Active CN218243500U (en) | 2022-08-11 | 2022-08-11 | Isolated signal input circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218243500U (en) |
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2022
- 2022-08-11 CN CN202222111584.2U patent/CN218243500U/en active Active
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