Utility model content
The main purpose of the utility model is to provide for LED in a kind of biochemical substances detecting instrument based on optical means
Light source is driven, the driving light source of LED used in the biochemical substances detecting instrument based on optical means is optimized, is provided
A kind of LED driving light source that can have stable constant current output and dimming function.
The purpose of this utility model can reach by using following technical solution:
LED drives light source, including AD823 operational amplifier in a kind of biochemical substances detecting instrument based on optical means
U5B, it is electrically connected with the AD823 operational amplifier U5B AD823 operational amplifier U5A being electrically connected and with AD823 operational amplifier U5A
The AD823 operational amplifier U6A connect;
The input terminal of AD823 operational amplifier U5B is in series with resistance R6, R7 and R8, between resistance R6, R7 and R8 three simultaneously
Connection, is parallel with resistance R5 between resistance R6 and resistance R7, the output end of AD823 operational amplifier U5B is in series with resistance R14,
Resistance R11, resistance R14 and AD823 operational amplifier are parallel between the input terminal and output end of AD823 operational amplifier U5B
The input terminal of U5A is connected;
The input terminal of AD823 operational amplifier U5A is also in series with resistance R45, and resistance R14 is in parallel with R45, AD823 operation
The output end of amplifier U5A is in series with resistance R15, and the input terminal and output end of AD823 operational amplifier U5A is parallel with resistance
R16, resistance R15 connect with the input terminal of AD823 operational amplifier U6A;
The input terminal of AD823 operational amplifier U6A is also in series with resistance R10, the output end of AD823 operational amplifier U6A
It is in series with resistance R9, the input terminal and output end of AD823 operational amplifier U6A is parallel with resistance R13;
Resistance R9 is connected by triode Q2 with triode Q1, and triode Q1 is connected by P-channel with triode Q4, three poles
Pipe Q4 and triode Q5 series LED switch control pin LED_EN carries out LED light driving.
Further, the one end the resistance R5 connects AGND, and the other end is connected with triode Q1, triode Q1 and triode
Resistance R39 is in series between Q2, resistance R39 is in series with resistance R12, in parallel between the one end resistance R12 and triode Q2, the other end
Connect AGND.
Further, the resistance R45 connects with voltage U7, and voltage U7 passes through series resistance R49 and control pin LED_
Level connection, voltage U7 are also in series with capacitor C11 and inductance L9, and inductance L9 connects 5V power supply, and capacitor C11 meets AGND, and voltage U7 makes
The switching selection for realizing constant current output is switched with TS12A12511 high performance analog, LED_level is range switching control
Pin.
Further, when LED_level is low level, resistance R45 does not access circuit, the voltage warp on sampling resistor R5
Differential amplification and the amplification of AD823 operational amplifier U5A amplifier for crossing AD823 operational amplifier U5B, put using AD823 operation
Big device U6A subtraction circuit, finally controls the on-off of the MMBT2222A and BD243C of triode Q5, and control constant current driving current is
45ma。
Further, when LED_level is high level, resistance R45 accesses circuit, and the voltage on sampling resistor R5 passes through
The differential amplification and AD823 operational amplifier U5A amplifier of AD823 operational amplifier U5B amplifies, using AD823 operation amplifier
Device U6A subtraction circuit, finally controls the on-off of the MMBT2222A and BD243C of triode Q5, and control constant current driving current is
145ma。
Further, AD823 operational amplifier U5B, AD823 operational amplifier U5A and AD823 operational amplifier U6A is equal
It is binary channels, precision, 16MHz, JFET input operational amplifier, using 3.0V-36V single supply or ± 1.5V- ± 18V dual power supply
Power supply.
Further, resistance R13 connects with the resistance R9 of AD823 operational amplifier U6A output end, and resistance R13 is also in parallel
There are capacitor C9, AD823 operational amplifier U6A and triode Q2 to be also in series with capacitor C8 and inductance L7, inductance L7 connects 9V power supply, electricity
Hold C8 and meets AGND.
Further, it connects between triode Q1 and triode Q4 the 1st and the 2nd payment to a porter of optocoupler P4, the 3rd of optocoupler P4 connects
The 4th payment to a porter of AGND, optocoupler P4 are parallel with resistance R30 and capacitor C65, and resistance R30 is in parallel with capacitor C65, the 4th foot of optocoupler P4
Line series connection MCU control interface MCU_ADC.
Further, the 3rd payment to a porter of the 3rd payment to a porter series connection the arrester F1, triode Q5 of triode Q4 are with triode Q4's
The 1st payment to a porter of series resistance R36 between series resistance R34 between 3rd payment to a porter, and the 1st payment to a porter of triode Q4, triode Q5 are logical
The 2nd payment to a porter for crossing resistance R38 series LED switch control pin LED_EN, triode Q5 meets AGND.
The advantageous effects of the utility model: the biochemical substances detector provided by the utility model based on optical means
LED drives light source in device, and constant current drives stability good, high reliablity, and LED drives light source to be able to satisfy there are two the switching of range
Test equipment need to measure in actual use sample solution it is excessively high or too low in the case where test data.
Specific embodiment
To make the more clear and clear the technical solution of the utility model of those skilled in the art, below with reference to embodiment and
Attached drawing is described in further detail the utility model, and however, the embodiments of the present invention are not limited thereto.
As shown in Fig. 2, LED drives light source in the biochemical substances detecting instrument provided in this embodiment based on optical means,
Including AD823 operational amplifier U5B, with the AD823 operational amplifier U5B AD823 operational amplifier U5A being electrically connected and with
The AD823 operational amplifier U6A of AD823 operational amplifier U5A electrical connection;
The input terminal of AD823 operational amplifier U5B is in series with resistance R6, R7 and R8, between resistance R6, R7 and R8 three simultaneously
Connection, is parallel with resistance R5 between resistance R6 and resistance R7, the output end of AD823 operational amplifier U5B is in series with resistance R14,
Resistance R11, resistance R14 and AD823 operational amplifier are parallel between the input terminal and output end of AD823 operational amplifier U5B
The input terminal of U5A is connected;
The input terminal of AD823 operational amplifier U5A is also in series with resistance R45, and resistance R14 is in parallel with R45, AD823 operation
The output end of amplifier U5A is in series with resistance R15, and the input terminal and output end of AD823 operational amplifier U5A is parallel with resistance
R16, resistance R15 connect with the input terminal of AD823 operational amplifier U6A;
The input terminal of AD823 operational amplifier U6A is also in series with resistance R10, the output end of AD823 operational amplifier U6A
It is in series with resistance R9, the input terminal and output end of AD823 operational amplifier U6A is parallel with resistance R13;
Resistance R9 is connected by triode Q2 with triode Q1, and triode Q1 is connected by P-channel with triode Q4, three poles
Pipe Q4 and triode Q5 series LED switch control pin LED_EN carries out LED light driving.
In the present embodiment, as shown in Fig. 2, the one end the resistance R5 connects AGND, the other end is connected with triode Q1, and three
Resistance R39 is in series between pole pipe Q1 and triode Q2, resistance R39 is in series with resistance R12, the one end resistance R12 and triode Q2
Between it is in parallel, the other end connects AGND, and the resistance R45 connects with voltage U7, and voltage U7 is drawn by series resistance R49 with control
Foot LED_level connection, voltage U7 are also in series with capacitor C11 and inductance L9, and inductance L9 connects 5V power supply, and capacitor C11 meets AGND, electricity
U7 is pressed to realize that the switching of constant current output selects using TS12A12511 high performance analog switch, LED_level cuts for range
Change control pin.
In the present embodiment, as shown in Fig. 2, when LED_level is low level, resistance R45 does not access circuit, sampling electricity
Differential amplification and AD823 operational amplifier U5A amplifier amplification of the voltage on R5 Jing Guo AD823 operational amplifier U5B are hindered, then is passed through
AD823 operational amplifier U6A subtraction circuit is crossed, the on-off of the MMBT2222A and BD243C of triode Q5 are finally controlled, control is permanent
Stream driving current is 45ma;When LED_level is high level, resistance R45 accesses circuit, and the voltage on sampling resistor R5 passes through
The differential amplification and AD823 operational amplifier U5A amplifier of AD823 operational amplifier U5B amplifies, using AD823 operation amplifier
Device U6A subtraction circuit, finally controls the on-off of the MMBT2222A and BD243C of triode Q5, and control constant current driving current is
145ma。
In the present embodiment, as shown in Fig. 2, AD823 operational amplifier U5B, AD823 operational amplifier U5A and AD823 are transported
Calculating amplifier U6A is binary channels, precision, 16MHz, JFET input operational amplifier, using 3.0V-36V single supply or ±
1.5V- ± 18V dual power supply, resistance R13 connect with the resistance R9 of AD823 operational amplifier U6A output end, and resistance R13 is also
It is parallel with capacitor C9, AD823 operational amplifier U6A and triode Q2 and is also in series with capacitor C8 and inductance L7, inductance L7 connects 9V electricity
Source, capacitor C8 meet AGND.
In the present embodiment, as shown in Fig. 2, the 1st and the 2nd foot for the optocoupler P4 that connects between triode Q1 and triode Q4
Line, the 3rd of optocoupler P4 meet AGND, and the 4th payment to a porter of optocoupler P4 is parallel with resistance R30 and capacitor C65, and resistance R30 and capacitor C65 are simultaneously
Connection, the 3rd payment to a porter series connection arrester F1 of the 4th payment to a porter series connection the MCU control interface MCU_ADC, triode Q4 of optocoupler P4, triode
Series resistance between series resistance R34, and the 1st payment to a porter of triode Q4 between the 3rd payment to a porter of Q5 and the 3rd payment to a porter of triode Q4
The 1st payment to a porter of R36, triode Q5 are connect by resistance R38 series LED switch control pin LED_EN, the 2nd payment to a porter of triode Q5
AGND。
In the present embodiment, as shown in Fig. 2, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drives the driving method of light source, includes the following steps:
Step 1: determining the normal use electric current I for driving light source in detecting instrument, determine that the rated operational current of electric current I is
60ma, maximum operating currenbt 150ma make its work in more satisfactory working condition;
Step 2: to used in the detecting instrument driving light source carry out constant current driving, electric current be respectively 45ma and
When 145ma, various concentration sample solution is detected, test data of the sample solution under excessive concentration or too low situation is measured;
Step 3: when LED_level is low level, resistance R45 does not access circuit, and the voltage on sampling resistor R5 passes through
The differential amplification and AD823 operational amplifier U5A amplifier of AD823 operational amplifier U5B amplifies, using AD823 operation amplifier
Device U6A subtraction circuit, finally controls the on-off of the MMBT2222A and BD243C of triode Q5, and control constant current driving current is
45ma;
Step 4: when LED_level is high level, resistance R45 accesses circuit, and the voltage on sampling resistor R5 passes through
The differential amplification and AD823 operational amplifier U5A amplifier of AD823 operational amplifier U5B amplifies, using AD823 operation amplifier
Device U6A subtraction circuit, finally controls the on-off of the MMBT2222A and BD243C of triode Q5, and control constant current driving current is
145ma。
In the present embodiment, as shown in Fig. 2, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drive light source, use PWM light modulation driving light source stability it is not good enough, zero load or have load in the case where detect
The fluctuation for the data that instrument measures is larger, and the light source of the single constant current driven used, cannot achieve dimming function,
This make test sample excessive concentration or it is too low in the case where, can not accurately measure data.
In the present embodiment, as shown in Fig. 2, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drives light source, is switched using TS12A12511 high performance analog and realizes that the switching of constant current output selects, source current has
The switching of two ranges of 45ma and 145ma.
LED_level is range switching control pin, and LED_EN is that LED switch controls pin, can be by being attached thereto
MCU issues control command to realize test request.
In the present embodiment, as shown in Fig. 2, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drives light source, and driver circuit carries out driving LED light using P-channel metal-oxide-semiconductor NTD2955, the passive device of this chip periphery
Few, at low cost, driving method is constant current driving, and the driving circuit driving current is big, can reach 1.3A, is much able to satisfy requirement,
For different driving light sources, the electric current in circuit can be improved according to the needs of user, as long as changing access simulation
The resistance of switch, so that it may meet the requirements.
In the present embodiment, as shown in Fig. 2, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drives light source, and in control route below, with cleverly designing, LED drive current is may be implemented in simple element
It is arbitrarily switched in two ranges of 45ma and 145ma, to achieve the effect that control, above-mentioned circuit reduction, element is few, reliably
Performance is high, is a kind of preferable control circuit.
In the present embodiment, as shown in Fig. 2, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drives light source, its working principles are as follows:
The normal use electric current (I) for driving light source in detecting instrument is determined, makes its work in more satisfactory work shape
State drives light source as used in the detecting instrument referred in the present embodiment, and rated operational current is 60ma, maximum work
Electric current can achieve 150ma.
Constant current driving is carried out to driving light source used in the detecting instrument, the sample for detecting various concentration in an experiment is molten
Liquid, as a result, it has been found that driving current test sample solution in 45ma and 145ma, can accurately measure sample solution dense
Spend the test data in high or too low situation.
As shown in Fig. 2, under normal circumstances, LED_level is low level, R45 does not access circuit at this time, on sampling resistor R5
Voltage by AD823 U5B differential amplification and amplifier AD823 U5A amplification, using the subtraction of the U6A of amplifier AD823
Circuit, and then the on-off of triode MMBT2222A and BD243C are controlled, realize constant current driving, driving current at this time is 45ma.
When LED_level is high level, R45 accesses circuit at this time, and the voltage on sampling resistor R5 passes through the U5B of AD823
Differential amplification and amplifier AD823 U5A amplification, using the subtraction circuit of the U6A of amplifier AD823, finally control triode
The on-off of MMBT2222A and BD243C realizes constant current driving, and driving current at this time is 145ma.
AD823 is a binary channels, precision, 16MHz, JFET input operational amplifier, and 3.0V can be used to 36V single supply
Or ± 1.5V, to ± 18V dual power supply, the circuit control is convenient, and circuit is simple, provides guarantee for stability, reliability is big
It is big to improve.
In conclusion in the present embodiment, in the biochemical substances detecting instrument provided in this embodiment based on optical means
LED drives light source, and constant current drives stability good, high reliablity, and LED drives light source to be able to satisfy test there are two the switching of range
Instrument need to measure in actual use sample solution it is excessively high or too low in the case where test data.
The above, only the utility model further embodiment, but the protection scope of the utility model is not limited to
In this, anyone skilled in the art is according to the present utility model in range disclosed in the utility model
Technical solution and its design are subject to equivalent substitution or change, belong to the protection scope of the utility model.