CN103743481B - A kind of adjustable light intensity detection circuit of very low cost detection range - Google Patents
A kind of adjustable light intensity detection circuit of very low cost detection range Download PDFInfo
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- CN103743481B CN103743481B CN201310667387.1A CN201310667387A CN103743481B CN 103743481 B CN103743481 B CN 103743481B CN 201310667387 A CN201310667387 A CN 201310667387A CN 103743481 B CN103743481 B CN 103743481B
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- light intensity
- npn triode
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- detection circuit
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Abstract
The present invention relates to a kind of adjustable light intensity detection circuit of very low cost detection range, is made up of four analog devices, i.e., one silicon phototriode U1 and a NPN triode Q1 and two resistance and a single-chip microprocessor MCU with AD samplings；Silicon phototriode U1 is connected with load R2, and the silicon phototriode U1 of the series connection and load R2 are in parallel with adjustable resistance R1；1 foot of adjustable resistance R1 and NPN triode Q1,2 feet are connected, and load R2 is connected with 3 feet of NPN triode Q1, and the outfan OUT that 3 feet of NPN triode Q1 pass through in single-chip microprocessor MCU is connected with single-chip microprocessor MCU.Beneficial effects of the present invention are：Simple and practical, with low cost, measurement range scalable；This circuit is particularly suitable for that required precision is not high, but the region that measurement range is adjustable and cost control is particularly severe.
Description
Technical field
A kind of a kind of the present invention relates to detection circuit, more particularly to the adjustable light-intensity test electricity of very low cost detection range
Road.
Background technology
Tradition is by light-sensitive device to the detection method of light intensity（Light sensitive diode, or photosensory assembly）Sensing illumination
Intensity, is made optical signal be converted into the signal of telecommunication, then weak electric signal is amplified using discharge circuit, then passes through analog/digital
Intensity signal is converted into digital information by change-over circuit.These light intensity digital informations with respect to a reference table, so as to be calculated
The intensity of light.
Although the method for this light-intensity test implement also do not include too complicated, if using photosensory assembly, relative
For price can be higher；If using simple light sensitive diode, photosensitive linear zone is narrow and dark current meeting
Variation with temperature is in nonlinear change, and measurement error can be than larger, it is most important that the light-intensity test of wide scope difficult to realize.
Content of the invention
It is an object of the invention to overcoming the shortcomings of that prior art is present, and provide a kind of to measurement range and certainty of measurement
Consider and the adjustable light intensity detection circuit of detection range that cost is extremely low.
The purpose of the present invention by following technical solution completing, the light intensity detection circuit totally four analog devices
Composition, i.e., one silicon phototriode U1 and a NPN triode Q1 and two resistance and a single-chip microcomputer with AD samplings
MCU；Together with described silicon phototriode U1 is connected with load R2, series connection silicon phototriode U1 together and load R2
In parallel with adjustable resistance R1；1 foot of adjustable resistance R1 and NPN triode Q1,2 feet are connected, and load the 3 of R2 and NPN triode Q1
Foot is connected, and 3 feet of the NPN triode Q1 are connected with single-chip microprocessor MCU by the outfan OUT in single-chip microprocessor MCU.Described silicon light
Light intensity signal is converted into the signal of telecommunication as the sensor devices of light intensity detection circuit by quick audion U1, is amplified through NPN triode Q1
Directly input after signal and sampled to single-chip microprocessor MCU and processed, obtain the light intensity in region；After be loaded into load R2 on, formed
Voltage signal for actual measurement.
Preferably, the detection optical wavelength of described silicon phototriode U1 is from 150～1200nm, i.e., to spectral wavelength from
The light of 150～1200nm can sense, and 390～770nm of visible region is also included wherein, also included 10～400nm areas
Between ultraviolet range, and the infrared part region of 760nm wavelengths above.
Preferably, on the one hand described adjustable resistance R1 will digest the dark current of silicon phototriode U1 itself, separately
On the one hand the signal of telecommunication that sensing is obtained is offset to the linear amplification region of NPN triode Q1.
Preferably, described NPN triode Q1 makes the running voltage of silicon phototriode U1 be held in running voltage
VCC-0.7V.
Beneficial effects of the present invention are：Simple and practical, with low cost, measurement range scalable；Temperature drift is not contained in circuit
Compensating device, will such as realize high-precision applications, then will increase warming device, and the temperature characterisitic of silicon phototriode is linear
, can be compensated according to temperature conditionss inside single-chip microcomputer, circuit precision can so increased；So circuit is particularly suitable for
It is applied to that required precision is not high, but the region that measurement range is adjustable and cost control is particularly severe.
Description of the drawings
Fig. 1 is circuit used in the present invention.
Fig. 2 is induction sensitivity curve of the silicon phototriode to different frequency light.
Fig. 3 is the faradic current curve of different temperatures under same light intensity.
Fig. 4 is faradic current curve under different light intensity environment.
Fig. 5 is silicon phototriode dark current curve at different temperatures.
Specific embodiment
Detailed introduction is done to the present invention below in conjunction with accompanying drawing：As shown in Figure 1, the present invention includes a cheap silicon
Phototriode U1 and a NPN triode Q1 the most common and two resistance and a single-chip microprocessor MCU group with AD samplings
Into cost is extremely low.The light intensity detection circuit is used as sensor devices by silicon phototriode U1, and light intensity signal is converted into telecommunications
Number, no matter light intensity signal is direct current signal or the 50HZ signals as daylight lamp, and silicon phototriode U1 accurately can feel
Should.Adjustable resistance R1 in circuit, on the one hand can digest the dark current of silicon phototriode U1 itself, on the other hand can
Play a part of the linear amplification region that the signal of telecommunication that sensing is obtained is offset to NPN triode Q1.NPN triode Q1 is mainly
To amplification to the signal of telecommunication, by amplification after current signal be loaded on load R2, can be used for actual survey so as to be formed
The voltage signal of amount.The precision for being sized to arrange detection intensity signal of regulating load R2 resistances, typically we do not go to arrange
Load R2 is arranged to a customization in calculating below by this value, and during this definite value, certainty of measurement is lower limit.
The light intensity detection circuit, causes internal resistance and mistake by the different sensings of silicon phototriode U1 senses light intensities
The change of stream ability carrys out conversion zone light intensity, and voltage defended by the PN junction pincers in the BE ends of NPN triode Q1 makes silicon phototriode U1
Running voltage remain running voltage VCC-0.7V, NPN triodes Q1 the signal of telecommunication that sensing is obtained is amplified after directly
Input to single-chip microprocessor MCU to be sampled and processed, so as to obtain the light intensity in region.
Fig. 1 is the circuit of the present invention, and in circuit, VCC is running voltage, and U1 is silicon phototriode, and Q1 is three pole of NPN type
Pipe（Amplification coefficient is He）, R1 is adjustable resistance, and R2 is load.Adjustable resistance R1 can remove the portion that phototriode stream U1 is crossed
Divide electric current, adjustable resistance R1 both end voltages are 0.7V, and compensation electric current is Ix=0.7V/R1, and effect is for removing dark current and tune
Section detection interval.
Fig. 2 can learn this silicon phototriode U1（PT19-21C-L41-TR8 of the product for EVERLIGHT companies）Right
Spectral wavelength can be sensed from the light of 150～1200nm, 390～770nm of visible region is also included wherein, also included 10
The interval ultraviolet ranges of～400nm, and the infrared part region of 760nm wavelengths above.
It is a straight line to the induction sensitivity curve of temperature that Fig. 3 can obtain silicon phototriode U1, and slope K is taken the photograph with 25
Family name's degree is with reference to sensitivity α=1, α=1+ (T-25 DEG C) * K during other temperature T.K can be obtained from figure.
It is a straight line that Fig. 4 can obtain silicon phototriode U1 to turn electric homologous thread to light, and slope is J, with 1mW light intensity
Be with reference to switching current be 0.6mA, during other light intensity Ee switching current be Ie=0.6+（Ee-1mW）*J.J can be obtained from figure
Arrive.
It is a straight line that Fig. 5 can obtain the homologous thread of silicon phototriode U1 dark current under different temperatures, and slope is L,
It is as 10 with reference to dark current with 25 degrees Celsius-6MA, then the dark current Ia=10 at other temperature T-6+(T-25℃)*L.L can be with
Obtain from figure.
According to above parameter and data, we can be calculated the magnitude of voltage Ve changed out under certain light intensity Ee by Fig. 1, and
And dark current and temperature drift can be compensated according to temperature T.It is calculated as follows：
I1=switching currents * induction sensitivities+dark current-compensation electric current
=Ie*α+Ia-Ix
=【0.6+(Ee-1mW)*J】*【1+(T-25℃)*K】+10-6+(T-25℃)*L-0.7/R1
R1 units are K Ω, current unit mA.
Electric current after amplifying through audion
I2=I1*He
={【0.6+(Ee-1mW)*J】*【1+(T-25℃)*K】+10-6+(T-25℃)*L-0.7/R1}*He
Load terminal voltage
Ve=VCC-I2*R2
=VCC-{【0.6+(Ee-1mW)*J】*【1+(T-25℃)*K】+10-6+(T-25℃)*L-0.7/R1}*He
It is unknown number to there was only light intensity Ee in above formula, therefore the magnitude of voltage Ve meters that single-chip microprocessor MCU can be obtained according to measurement
Calculate region light intensity Ee.
It is understood that it will be understood by those skilled in the art that to technical scheme and inventive concept in addition etc.
With the protection domain that replacement or change should all belong to appended claims of the invention.
Claims (2)
1. the adjustable light intensity detection circuit of a kind of very low cost detection range, it is characterised in that：The light intensity detection circuit totally four
Individual analog device composition, i.e., one silicon phototriode U1 and a NPN triode Q1 and two resistance and a band AD are sampled
Single-chip microprocessor MCU；Described silicon phototriode U1 with load R2 connect together with, series connection silicon phototriode U1 together with
R2 is in parallel with adjustable resistance R1 for load；1 foot of adjustable resistance R1 and NPN triode Q1,2 feet are connected, load R2 and NPN triode
3 feet of Q1 are connected, and 3 feet of the NPN triode Q1 are connected with single-chip microprocessor MCU by the outfan OUT in single-chip microprocessor MCU；Described
Silicon phototriode U1 as the sensor devices of light intensity detection circuit, light intensity signal is converted into the signal of telecommunication, through NPN triode
Q1 is directly inputted after amplifying signal and is sampled to single-chip microprocessor MCU and processed, and obtains the light intensity in region；After be loaded into load R2
On, form the voltage signal for actual measurement；On the one hand described adjustable resistance R1 will digest silicon phototriode U1 certainly
The dark current of body, on the other hand the signal of telecommunication that sensing is obtained is offset to the linear amplification region of NPN triode Q1, described silicon light
The detection optical wavelength of quick audion U1 can be sensed from the light of 150 ~ 1200nm to spectral wavelength from 150 ~ 1200nm, to can
See that 390 ~ 770nm of light region is also included wherein, also included the interval ultraviolet ranges of 10 ~ 400nm, and 760nm wavelengths above
Infrared part region.
2. the adjustable light intensity detection circuit of very low cost detection range according to claim 1, it is characterised in that：Described
NPN triode Q1 makes the running voltage of silicon phototriode U1 be held in running voltage VCC-0.7V.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201310667387.1A CN103743481B (en) | 2014-02-20 | 2014-02-20 | A kind of adjustable light intensity detection circuit of very low cost detection range |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310667387.1A CN103743481B (en) | 2014-02-20 | 2014-02-20 | A kind of adjustable light intensity detection circuit of very low cost detection range |
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| CN103743481A CN103743481A (en) | 2014-04-23 |
| CN103743481B true CN103743481B (en) | 2017-03-15 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN106066397B (en) * | 2016-07-05 | 2019-10-18 | 深圳普门科技股份有限公司 | A kind of compensation system, method and immunity analysis instrument suitable for current-output type photomultiplier tube |
| CN113884154B (en) * | 2020-07-03 | 2023-10-31 | 成都秦川物联网科技股份有限公司 | MCU-based double-path photoelectric sampling method for intelligent gas meter of Internet of things |
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|---|---|---|---|---|
| US3813539A (en) * | 1973-01-31 | 1974-05-28 | Rohm & Haas | Electro-optical coupler unit |
| US3870418A (en) * | 1971-06-25 | 1975-03-11 | Canon Kk | Exposure meter |
| US5043587A (en) * | 1989-01-17 | 1991-08-27 | Fuji Electric Co., Ltd. | Photocoupler circuit having DC power source in series with detection and switching means |
| JP2009097870A (en) * | 2007-10-12 | 2009-05-07 | Sony Corp | Optical-electrical signal conversion circuit and light detection device |
| CN102062810A (en) * | 2010-12-14 | 2011-05-18 | 江苏大学 | Detection circuit and method for zero crossing point of alternating current power supply |
| CN103376157A (en) * | 2012-04-20 | 2013-10-30 | 海洋王（东莞）照明科技有限公司 | Lamp luminance detecting device |
| CN203745081U (en) * | 2014-02-20 | 2014-07-30 | 三维通信股份有限公司 | Extremely-low-lost adjustable-detection-range light intensity detection circuit |
-
2014
- 2014-02-20 CN CN201310667387.1A patent/CN103743481B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3870418A (en) * | 1971-06-25 | 1975-03-11 | Canon Kk | Exposure meter |
| US3813539A (en) * | 1973-01-31 | 1974-05-28 | Rohm & Haas | Electro-optical coupler unit |
| US5043587A (en) * | 1989-01-17 | 1991-08-27 | Fuji Electric Co., Ltd. | Photocoupler circuit having DC power source in series with detection and switching means |
| JP2009097870A (en) * | 2007-10-12 | 2009-05-07 | Sony Corp | Optical-electrical signal conversion circuit and light detection device |
| CN102062810A (en) * | 2010-12-14 | 2011-05-18 | 江苏大学 | Detection circuit and method for zero crossing point of alternating current power supply |
| CN103376157A (en) * | 2012-04-20 | 2013-10-30 | 海洋王（东莞）照明科技有限公司 | Lamp luminance detecting device |
| CN203745081U (en) * | 2014-02-20 | 2014-07-30 | 三维通信股份有限公司 | Extremely-low-lost adjustable-detection-range light intensity detection circuit |
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