CN219285322U - Phototriode detection circuit - Google Patents
Phototriode detection circuit Download PDFInfo
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- CN219285322U CN219285322U CN202223257234.3U CN202223257234U CN219285322U CN 219285322 U CN219285322 U CN 219285322U CN 202223257234 U CN202223257234 U CN 202223257234U CN 219285322 U CN219285322 U CN 219285322U
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Abstract
The utility model discloses a phototriode detection circuit, wherein one end of a phototriode is connected with a power supply, the other end of the phototriode is connected with one end of an emitter resistor, the other end of the emitter resistor is grounded, one end of the emitter resistor connected with the phototriode is also connected with a differential amplifying circuit and a first input end of a second analog switch respectively, an output end of the second analog switch is connected with one end of a current-limiting resistor, the other end of the current-limiting resistor is connected with a non-inverting input end of a first operational amplifier, the output end of the first operational amplifier is connected with a differential amplifying circuit, the output end of the first operational amplifier is also connected with a reverse input end of the first operational amplifier, one end of a capacitor is connected with a same-direction input end of the first operational amplifier, and the other end of the capacitor is grounded. The beneficial effects are that: the circuit has simple structure and simple control logic, can remove the influence of ambient light and dark current, does not need to take compensation measures subsequently, and has high detection precision.
Description
Technical Field
The utility model relates to the technical field of photoelectric detection, in particular to a phototriode detection circuit.
Background
The current of the phototriode is controlled by external illumination, and the phototriode is a semiconductor photoelectric device. The phototriode is a triode which is equivalent to a photodiode connected between the base electrode and the collector electrode of the triode, and the current of the photodiode is equivalent to the base current of the triode. When no light is irradiated, the phototriode is in a cut-off state, and no electric signal is output. When the base electrode of the phototriode is irradiated by the optical signal, the phototriode is conducted, photoelectric conversion is realized through the photodiode, then the amplification of photocurrent is realized through the triode, and the amplified electric signal is output from the emitter electrode or the collector electrode. Thus, a phototransistor is typically used to measure the intensity of light, for example, in a smoke detector a phototransistor is used to measure the intensity of infrared light scattered by smoke particles. However, the phototransistor is greatly affected by temperature, and the dark current of the phototransistor increases rapidly with increasing temperature, so that the output signal to noise ratio is poor, and the dark current can reach more than 50 microamps at the ambient temperature of 100 ℃. When the phototransistor is used for weak light detection, the current caused by the weak light signal is also microampere, so that the influence of temperature on the output of the photoelectric device is often required to be considered when the weak light detection is carried out, and a capacitive blocking circuit or a software compensation method is required to be adopted to remove the influence if necessary.
Disclosure of Invention
The utility model aims to overcome the defects of the prior art and provides a phototriode detection circuit which has simple circuit structure and simple control logic, can remove the influence of ambient light and dark current, does not need to take subsequent compensation measures and has high detection precision.
The aim of the utility model is achieved by the following technical measures: the utility model provides a phototriode detection circuit, includes phototriode and emitter resistance, the one end and the power of phototriode are connected, the other end and the one end of emitter resistance of phototriode are connected, the other end ground connection of emitter resistance still includes voltage holding circuit and differential amplifier circuit, voltage holding circuit includes a second choice analog switch, current-limiting resistor, electric capacity and first operational amplifier, the one end that emitter resistance and phototriode are connected still is connected with differential amplifier circuit and a second choice analog switch's first input respectively, the output of a second choice analog switch is connected with current-limiting resistor's one end, current-limiting resistor's the other end is connected with first operational amplifier's homophase input, first operational amplifier's output is connected with differential amplifier circuit, first operational amplifier's output still is connected with first operational amplifier's reverse input, the one end of electric capacity is connected with first operational amplifier's homonymous input, the other end ground connection of electric capacity.
Further, the voltage follower circuit is connected with the emitter resistor and the first input end of the alternative analog switch respectively.
Further, the voltage follower circuit comprises a second operational amplifier and a follower resistor, one end of the follower resistor is connected with the emitter resistor, the other end of the follower resistor is connected with the same-direction input end of the second operational amplifier, the output end of the second operational amplifier is connected with the first input end of the alternative analog switch, and the output end of the second operational amplifier is also connected with the reverse input end of the second operational amplifier.
Further, the differential amplifying circuit comprises a third operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor, one end of the third resistor is connected with the output end of the first operational amplifier, the other end of the third resistor is connected with the reverse input end of the third operational amplifier, one end of the second resistor is connected with the emitter resistor, the other end of the second resistor is connected with the same-direction input end of the third operational amplifier, the input end of the third operational amplifier is connected with one end of the first resistor, the other end of the first resistor is connected with the reverse input end of the third operational amplifier, the same-direction input end of the third operational amplifier is also connected with one end of the fourth resistor, and the other end of the fourth resistor is grounded.
Further, the first resistor and the fourth resistor have the same resistance, and the second resistor and the third resistor have the same resistance.
Further, the intelligent control device also comprises a controller, wherein the controller is connected with a control pin of the alternative analog switch.
Compared with the prior art, the utility model has the beneficial effects that: the phototriode detection circuit is simple in circuit structure, the influence of ambient light and dark current can be removed only by controlling the start and stop of a detection light source and the on-off of an alternative analog switch, and the circuit control logic is simple. The influence of ambient light and dark current can be directly removed through the arrangement of the circuit structure, no follow-up compensation measures are needed, and the detection precision is high.
The utility model is described in detail below with reference to the drawings and the detailed description.
Drawings
Fig. 1 is a schematic structural view of the present utility model.
The three-phase current limiting circuit comprises a phototriode 1, an emitter resistor 2, an emitter resistor 3, a follower resistor 4, a second operational amplifier 5, an alternative analog switch 6, a current limiting resistor 7, a first operational amplifier 8, a third resistor 9, a second resistor 10, a first resistor 11, a fourth resistor 12, a third operational amplifier 13 and a capacitor.
Detailed Description
As shown in fig. 1, a phototransistor detection circuit includes a phototransistor 1 and an emitter resistor 2, one end of the phototransistor 1 is connected with a power supply, the other end of the phototransistor 1 is connected with one end of the emitter resistor 2, the other end of the emitter resistor 2 is grounded, and a current signal flowing through the phototransistor 1 is converted into a voltage signal through the emitter resistor 2. The voltage holding circuit comprises a second analog switch 5, a current limiting resistor 6, a capacitor 13 and a first operational amplifier 7, wherein one end of the emitter resistor 2 connected with the phototriode 1 is further connected with the differential amplifier and the first input end of the second analog switch 5 respectively, the output end of the second analog switch 5 is connected with one end of the current limiting resistor 6, the other end of the current limiting resistor 6 is connected with the non-inverting input end of the first operational amplifier 7, the output end of the first operational amplifier 7 is connected with the differential amplifier, the output end of the first operational amplifier 7 is further connected with the inverting input end of the first operational amplifier 7, one end of the capacitor 13 is connected with the homodromous input end of the first operational amplifier 7, and the other end of the capacitor 13 is grounded. Specifically, the alternative analog switch 5 includes two input terminals, i.e., a first input terminal and a second input terminal, and an output terminal, which may be in communication with one of the first input terminal and the second input terminal. When the detection light source is not started, the first input end of the alternative analog switch 5 is communicated with the output end of the alternative analog switch, and when the detection light source is started, the second input end of the alternative analog switch 5 is communicated with the output end of the alternative analog switch. When weak light detection is needed, the detection light source is turned off firstly, the phototriode 1 generates dark current due to temperature change or generates interference current due to receiving ambient light, the emitter resistor 2 converts the dark current and the interference current into voltage signals, the voltage signals are output by the alternative analog switch 5 and then flow through the current limiting resistor 6 to charge the capacitor 13, and the voltage signals are transmitted to the differential amplification circuit through the first operational amplifier 7, at the moment, the differential amplification circuit also directly receives the voltage signals at the emitter resistor 2, therefore, the output end of the differential amplification circuit outputs a voltage difference value, when the voltage difference value is 0, the capacitor 13 is completely charged, and the voltage value of the capacitor 13 is identical with the interference voltage signals generated due to temperature change and the ambient light. After the capacitor 13 is charged, the second input end of the alternative analog switch 5 is controlled to be communicated with the output end of the alternative analog switch 5 even if the alternative analog switch 5 is in a suspended state, at this time, the voltage of the capacitor 13 maintains the same voltage as the interference voltage signal generated by temperature change and ambient light, then the detection light source is started to irradiate the phototriode 1, and the voltage of the emitter resistor 2 can only be directly transmitted to the differential amplifying circuit because the alternative analog switch 5 is in the suspended state, and at this time, the voltage difference value output by the differential amplifying circuit is the electric signal generated by irradiation of the detection light source. The influence of ambient light and dark current is directly removed in weak light detection through processes of charging the capacitor 13, suspending the alternative analog switch 5, detecting the light source and the like, compensation measures are not needed to be taken subsequently, and the detection precision is high.
The voltage follower circuit is connected with the emitter resistor 2 and the first input end of the alternative analog switch 5 respectively. By utilizing the characteristics of the voltage follower circuit, such as high input resistance, low output resistance and approximately 1 voltage gain, the charging speed of the capacitor 13 can be increased, and the detection efficiency can be improved.
The voltage follower circuit comprises a second operational amplifier 4 and a follower resistor 3, one end of the follower resistor 3 is connected with the emitter resistor 2, the other end of the follower resistor 3 is connected with the homodromous input end of the second operational amplifier 4, the output end of the second operational amplifier 4 is connected with the first input end of the alternative analog switch 5, and the output end of the second operational amplifier 4 is also connected with the reverse input end of the second operational amplifier 4. The arrangement of the follower resistor 3 can be used to protect the second operational amplifier 4 from damaging the second operational amplifier 4 due to the large voltage generated by the phototransistor 1.
The differential amplifying circuit comprises a third operational amplifier 12, a first resistor 10, a second resistor 9, a third resistor 8 and a fourth resistor 11, wherein one end of the third resistor 8 is connected with the output end of the first operational amplifier 7, the other end of the third resistor 8 is connected with the reverse input end of the third operational amplifier 12, one end of the second resistor 9 is connected with the emitter resistor 2, the other end of the second resistor 9 is connected with the same-direction input end of the third operational amplifier 12, the input end of the third operational amplifier 12 is connected with one end of the first resistor 10, the other end of the first resistor 10 is connected with the reverse input end of the third operational amplifier 12, the same-direction input end of the third operational amplifier 12 is also connected with one end of the fourth resistor 11, and the other end of the fourth resistor 11 is grounded. Further, the first resistor 10 and the fourth resistor 11 have the same resistance, and the second resistor 9 and the third resistor 8 have the same resistance.
The controller is connected with a control pin of the alternative analog switch 5, and the on-off state of the alternative analog switch 5 can be controlled by the controller. In addition, the controller can also be connected with the output end of the differential amplifying circuit, and the differential amplifying circuit transmits a difference signal to the controller.
It will be understood by those skilled in the art that the present utility model is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present utility model, and various changes and modifications may be made without departing from the spirit and scope of the utility model, which is defined in the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.
Claims (6)
1. The utility model provides a phototriode detection circuit, includes phototriode and emitter resistance, the one end and the power of phototriode are connected, the other end and the one end of emitter resistance of phototriode are connected, the other end ground connection of emitter resistance, its characterized in that: the voltage holding circuit comprises a second analog switch, a current limiting resistor, a capacitor and a first operational amplifier, wherein one end of the emitter resistor, which is connected with the phototriode, is further connected with the differential amplifying circuit and the first input end of the second analog switch respectively, the output end of the second analog switch is connected with one end of the current limiting resistor, the other end of the current limiting resistor is connected with the non-inverting input end of the first operational amplifier, the output end of the first operational amplifier is connected with the differential amplifying circuit, the output end of the first operational amplifier is further connected with the inverting input end of the first operational amplifier, one end of the capacitor is connected with the homodromous input end of the first operational amplifier, and the other end of the capacitor is grounded.
2. The phototransistor detection circuit as recited in claim 1, wherein: the voltage follower circuit is connected with the emitter resistor and the first input end of the alternative analog switch respectively.
3. The phototransistor detection circuit as recited in claim 2, wherein: the voltage follower circuit comprises a second operational amplifier and a follower resistor, one end of the follower resistor is connected with the emitter resistor, the other end of the follower resistor is connected with the same-direction input end of the second operational amplifier, the output end of the second operational amplifier is connected with the first input end of the alternative analog switch, and the output end of the second operational amplifier is also connected with the reverse input end of the second operational amplifier.
4. The phototransistor detection circuit as recited in claim 1, wherein: the differential amplifying circuit comprises a third operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor, wherein one end of the third resistor is connected with the output end of the first operational amplifier, the other end of the third resistor is connected with the reverse input end of the third operational amplifier, one end of the second resistor is connected with the emitter resistor, the other end of the second resistor is connected with the same-direction input end of the third operational amplifier, the input end of the third operational amplifier is connected with one end of the first resistor, the other end of the first resistor is connected with the reverse input end of the third operational amplifier, the same-direction input end of the third operational amplifier is also connected with one end of the fourth resistor, and the other end of the fourth resistor is grounded.
5. The phototransistor detection circuit as recited in claim 4, wherein: the resistance values of the first resistor and the fourth resistor are the same, and the resistance values of the second resistor and the third resistor are the same.
6. The phototransistor detection circuit as recited in claim 1, wherein: the controller is connected with a control pin of the alternative analog switch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223257234.3U CN219285322U (en) | 2022-12-03 | 2022-12-03 | Phototriode detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223257234.3U CN219285322U (en) | 2022-12-03 | 2022-12-03 | Phototriode detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN219285322U true CN219285322U (en) | 2023-06-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202223257234.3U Active CN219285322U (en) | 2022-12-03 | 2022-12-03 | Phototriode detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN219285322U (en) |
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2022
- 2022-12-03 CN CN202223257234.3U patent/CN219285322U/en active Active
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