CN104837283A - LED lamp brightness management circuit based on digital control - Google Patents
LED lamp brightness management circuit based on digital control Download PDFInfo
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- CN104837283A CN104837283A CN201510288048.1A CN201510288048A CN104837283A CN 104837283 A CN104837283 A CN 104837283A CN 201510288048 A CN201510288048 A CN 201510288048A CN 104837283 A CN104837283 A CN 104837283A
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Abstract
The invention discloses an LED lamp brightness management circuit based on digital control. The circuit comprises a digital potentiometer, an operational amplifier, an 8-channel latch register, a triode, a resistor and an LED lamp, wherein a ninth pin of the digital potentiometer is connected to a second pin of the operational amplifier, an eighth pin of the digital potentiometer is connected to a first pin of the operational amplifier, a sixth pin of the digital potentiometer is connected to a sixth pin of the operational amplifier, and a seventh pin of the digital potentiometer is connected to a seventh pin of the operational amplifier; and the first and seventh pins of the operational amplifier are connected to the anode of the LED lamp, the anode of the LED lamp is connected to the collector electrode of the triode, and the base electrode of the triode is connected to a pin of the 8-channel latch register. The digital potentiometer is used to accurately adjust the brightness value in a stepping manner, the problem that brightness change causes inaccurate detection results is overcome, and the circuit is simple in design and good in use effect.
Description
Technical field
The present invention relates to LED light emitting control in Multifunctional food safety detector testing process and accurately control applied technical field, particularly a kind of LED brightness management circuit based on Digital Control.
Background technology
At present, domestic Multifunctional food safety detector adopts manually adjustment LED luminance to make its brightness can detection range substantially, the potentiometer of manual adjustment is after product design completes, shading value is adjusted to rational scope to sell again, problem is that product introduction sales section can exist a large amount of transports, the process of circulation, and the movement of product itself in this process, the inner tap of potentiometer can be caused to change, the inner tap of photopotential device changes, LED divide electric current can along with changing, so there is larger fluctuation in the brightness of LED, if LED luminance is not in standard value range, the result error detected by this instrument can be very large, therefore the basic goal of food safety detection can have a greatly reduced quality.The sense channel that in most cases same equipment is different detects the checkout discrepancy of same sample also can be very large, and testing result is also different, and the food security of the people exists material risk.
The present invention focuses on the problem solving LED luminance stability, digital regulation resistance is adopted to realize the adjustable of LED luminance by the mode of programming, digital regulation resistance unlike common potentiometer by external environment change very greatly, digital regulation resistance itself is highly stable, this idea of LED luminance is adjusted feasible and reliable by digital regulation resistance, difficulty is that the electric current that digital regulation resistance itself can circulate is very limited, maximumly can not, more than 1mA, the electric current of tens mA be often needed to drive for LED luminance like this.So amplified according to certain amplification coefficient by complicated amplification appliance, that is preset to LED by Current amplifier lights requirement, then problem can fundamentally solve.
Summary of the invention
The object of the invention is to for the deficiencies in the prior art, a kind of LED brightness management circuit based on Digital Control is provided.
For solving the problem, the invention provides following technical scheme:
A kind of LED brightness management circuit based on Digital Control, comprise digital regulation resistance, operational amplifier, 8 passage lock storages, triode, resistance and LED, 9th pin of described digital regulation resistance is connected on the second pin of operational amplifier, 8th pin of described digital regulation resistance is connected on the first pin of operational amplifier, 6th pin of described digital regulation resistance is connected on the 6th pin of operational amplifier, and the 7th pin of described digital regulation resistance is connected on the 7th pin of operational amplifier; First pin of described operational amplifier is connected with the anode of LED respectively with the 7th pin, and the anode of described LED is connected on the collector electrode of triode, and the base stage of triode is connected on the pin of 8 passage lock storages.
Preferably, be also provided with a resistance R05 between the 8th pin of described digital regulation resistance and the first pin of operational amplifier, the first pin of described operational amplifier is also parallel with a resistance R04, and resistance R04 other end ground connection; Also be provided with a resistance R08 between 7th pin of described digital regulation resistance and the 7th pin of operational amplifier, the 7th pin of described operational amplifier is also parallel with a resistance R07, and resistance R07 other end ground connection.
Furtherly, the 5th pin of described digital regulation resistance is connected resistance R01 and R03 respectively with the tenth pin, and described resistance R01 is identical with R03 resistance and be respectively 2K Ω, and other end ground connection respectively.
Furtherly, the three-prong of described operational amplifier and the 5th pin are connected to a resistance R02 and resistance R06, described resistance R02 is identical with resistance R06 resistance and be respectively 10K Ω, and resistance R02 and the resistance R06 other end connect the direct voltage of 1.8V respectively.
Furtherly, first pin and the 7th pin of described operational amplifier are also parallel with three groups of LED respectively, described single group LED is also parallel on the collector electrode of triode Q1 and triode Q4 respectively, and on the base stage of triode Q1 and the triode Q4 pin one 8 that is connected respectively to 8 passage lock storages and pin one 9.
Furtherly, described one group of LED is controlled by 8 passage lock storages respectively, the chip controls of 74ALS573 model that what described 8 passage lock storages adopted is.
Furtherly, what described digital regulation resistance adopted is MCP42100 chip.
Adopt after technique scheme, the present invention compared to the prior art advantageously:
The present invention adopts digital regulation resistance can carry out step by step modulating to luminous value accurately.Also specially designed shading value correcting circuit and accurate algorithm bring stable light source and luminescence; Avoid shading value and change the inaccurate problem of the testing result brought, simultaneously by adjusting the different luminous value of light-emitting diode, increase light-emitting diode ageing time process in process of production, make equipment more stable when dispatching from the factory, avoid the problem of potentiometer deviation in transportation, and circuit design is simple, result of use is good.
Accompanying drawing explanation
Fig. 1 is the connection diagram of the LED brightness management circuit based on Digital Control of the present invention.
Embodiment
Below in conjunction with Figure of description and embodiment, specific embodiments of the invention are described in further detail:
A kind of LED brightness management circuit based on Digital Control as shown in Figure 1, comprises digital regulation resistance U1, operational amplifier, 8 passage lock storages, triode, resistance and LED, and what described digital regulation resistance U0 adopted is MCP42100 chip.9th pin of described digital regulation resistance U0 is connected on the second pin of operational amplifier, 8th pin of described digital regulation resistance U0 is connected on the first pin of operational amplifier, 6th pin of described described digital regulation resistance U0 is connected on the 6th pin of operational amplifier, and the 7th pin of described digital regulation resistance is connected on the 7th pin of operational amplifier; First pin of described operational amplifier is connected with the anode of LED respectively with the 7th pin, and the anode of described LED is connected on the collector electrode of triode, and the base stage of triode is connected on the pin of 8 passage lock storages.
Also be provided with a resistance R05 between 8th pin of described digital regulation resistance U0 and the first pin of operational amplifier, the first pin of described operational amplifier is also parallel with a resistance R04, and resistance R04 other end ground connection; Also be provided with a resistance R08 between 7th pin of described digital regulation resistance U0 and the 7th pin of operational amplifier, the 7th pin of described operational amplifier U0 is also parallel with a resistance R07, and resistance R07 other end ground connection.
5th pin of described digital regulation resistance U0 is connected resistance R01 and R03 respectively with the tenth pin, and described resistance R01 is identical with R03 resistance and be respectively 2K Ω, and other end ground connection respectively.
The three-prong of described operational amplifier U0 and the 5th pin are connected to a resistance R02 and resistance R06, simultaneously, resistance R02 is identical with resistance R06 resistance and be respectively 10K Ω, and resistance R02 and the resistance R06 other end connect the direct voltage of 1.8V respectively.
First pin and the 7th pin of described operational amplifier U0 are also parallel with three groups of LED respectively, described list group LED is also parallel on the collector electrode of triode Q1 and triode Q4 respectively, and on the base stage of triode Q1 and the triode Q4 pin one 8 that is connected respectively to 8 passage lock storages and pin one 9.
One group of described LED is controlled by 8 passage lock storages respectively, and meanwhile, what 8 passage lock storages adopted is the chip controls of 74ALS573 model.
Be described in further detail below in conjunction with the operation principle of accompanying drawing 1 to this circuit:
Schematic diagram chip functions illustrates:
Circuit start realizes each voltage access of VCC, and each chip has condition of work.Simultaneity factor determines the test item needing to detect, according to the LED of test item Systematic selection different wave length.(example: need to light first passage purple LED (D7C).)
Digital regulation resistance MCP42010 chip select line input signal (CS), enable MCP42010, MCP42010 are in running order, and MCP42010 carries out Data Control by I2C bus.
Because first passage lighted by needs, then need to allow A0 port working.First need to SI square wave, allow SI to MCP42010 clock signal.
Meanwhile, in order to make same group of voltage can drive the LED of different voltage.Again because LED controls to need to carry out break-make control, then LED strip has connected triode.
If when triode Q3 base stage is if high level, then purple LED (D7C) lights, need to allow U7 chip operation like this, then need to allow OE3 be in low level, allow U7 latch chip start working, 2D end is exported high level, such 74LS573 output 2Q exports high level, and triode Q3 base stage is in conducting state simultaneously.
Due to Q3 conducting, electric current can flow through Q3 by D7C and flow to earth terminal, and first passage purple LED (D7C) is in illuminating state.
If the brightness requirement of now LED (D7C) brightness and testing requirement is inconsistent, higher or on the low side, then input PW0 tap position data by SCK to MCP42010, change the resistance ratio of PB0 to PW0 and PA0 to PW0, the voltage amplification of such operational amplifier changes than regular meeting, be multiplied by pedestal voltage value again, the voltage being finally loaded into A0 end can change, thus the brightness of LED changes.Certainly strict control needs to increase divider resistance in LED front end.
If need now to change lighting and brightness of second channel green LED, then only need the value changing MCP42010 chip PW1, U6 is carried out sheet choosing simultaneously, U7 is latched.Just can light and the brightness of control LED (D8B).
The above, it is only preferred embodiment of the present invention, not any restriction is made to technical scope of the present invention, thus every above embodiment is done according to technical spirit of the present invention any trickle amendment, equivalent variations and modification, all still belong within the scope of technical scheme of the present invention.
Claims (7)
1. the LED brightness management circuit based on Digital Control, comprise digital regulation resistance, operational amplifier, 8 passage lock storages, triode, resistance and LED, it is characterized in that: the 9th pin of described digital regulation resistance is connected on the second pin of operational amplifier, 8th pin of described digital regulation resistance is connected on the first pin of operational amplifier, 6th pin of described digital regulation resistance is connected on the 6th pin of operational amplifier, and the 7th pin of described digital regulation resistance is connected on the 7th pin of operational amplifier; First pin of described operational amplifier is connected with the anode of LED respectively with the 7th pin, and the anode of described LED is connected on the collector electrode of triode, and the base stage of triode is connected on the pin of 8 passage lock storages.
2. a kind of LED brightness management circuit based on Digital Control according to claim 1, it is characterized in that: between the 8th pin of described digital regulation resistance and the first pin of operational amplifier, be also provided with a resistance R05, first pin of described operational amplifier is also parallel with a resistance R04, and resistance R04 other end ground connection; Also be provided with a resistance R08 between 7th pin of described digital regulation resistance and the 7th pin of operational amplifier, the 7th pin of described operational amplifier is also parallel with a resistance R07, and resistance R07 other end ground connection.
3. a kind of LED brightness management circuit based on Digital Control according to claim 1, it is characterized in that: the 5th pin of described digital regulation resistance is connected resistance R01 and R03 respectively with the tenth pin, described resistance R01 is identical with R03 resistance and be respectively 2K Ω, and other end ground connection respectively.
4. a kind of LED brightness management circuit based on Digital Control according to claim 1, it is characterized in that: the three-prong of described operational amplifier and the 5th pin are connected to a resistance R02 and resistance R06, described resistance R02 is identical with resistance R06 resistance and be respectively 10K Ω, and resistance R02 and the resistance R06 other end connect the direct voltage of 1.8V respectively.
5. a kind of LED brightness management circuit based on Digital Control according to claim 1, it is characterized in that: the first pin and the 7th pin of described operational amplifier are also parallel with three groups of LED respectively, described single group LED is also parallel on the collector electrode of triode Q1 and triode Q4 respectively, and on the base stage of triode Q1 and the triode Q4 pin one 8 that is connected respectively to 8 passage lock storages and pin one 9.
6. a kind of LED brightness management circuit based on Digital Control according to claim 5, is characterized in that: described one group of LED is controlled by 8 passage lock storages respectively, the chip controls of 74ALS573 model that what described 8 passage lock storages adopted is.
7. a kind of LED brightness management circuit based on Digital Control according to claim 1, is characterized in that: what described digital regulation resistance adopted is MCP42100 chip.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510288048.1A CN104837283A (en) | 2015-05-29 | 2015-05-29 | LED lamp brightness management circuit based on digital control |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510288048.1A CN104837283A (en) | 2015-05-29 | 2015-05-29 | LED lamp brightness management circuit based on digital control |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201191408Y (en) * | 2008-05-06 | 2009-02-04 | 江苏东大金智建筑智能化系统工程有限公司 | Infrared light source controller for finger vena image collecting |
| CN103702494A (en) * | 2014-01-09 | 2014-04-02 | 广德利德光电有限公司 | Two-pin RGB-LED (Red Green Blue-Light Emitting Diode) control circuit |
| CN204598439U (en) * | 2015-05-29 | 2015-08-26 | 湖北久华食安生物技术有限公司 | A kind of LED brightness management circuit based on Digital Control |
-
2015
- 2015-05-29 CN CN201510288048.1A patent/CN104837283A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201191408Y (en) * | 2008-05-06 | 2009-02-04 | 江苏东大金智建筑智能化系统工程有限公司 | Infrared light source controller for finger vena image collecting |
| CN103702494A (en) * | 2014-01-09 | 2014-04-02 | 广德利德光电有限公司 | Two-pin RGB-LED (Red Green Blue-Light Emitting Diode) control circuit |
| CN204598439U (en) * | 2015-05-29 | 2015-08-26 | 湖北久华食安生物技术有限公司 | A kind of LED brightness management circuit based on Digital Control |
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