CN208353661U - A kind of infrared light compensating lamp flow control circuit - Google Patents
A kind of infrared light compensating lamp flow control circuit Download PDFInfo
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- CN208353661U CN208353661U CN201820933344.1U CN201820933344U CN208353661U CN 208353661 U CN208353661 U CN 208353661U CN 201820933344 U CN201820933344 U CN 201820933344U CN 208353661 U CN208353661 U CN 208353661U
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Abstract
The utility model discloses a kind of infrared light compensating lamp flow control circuits, including access LED electroluminescent lamp interface J3 and bleeder circuit U3;The both ends of LED electroluminescent lamp interface J3 are separately connected the positive and negative polarities of LED electroluminescent lamp, are respectively as follows: VDD_LED and VDD_LED-;Bleeder circuit U3 is the integrated circuit of SGM3749YTD16G model, the integrated circuit is provided with 7 pins, No. 1 pin is directly connected VDD_LED-, and is divided in the front end that is connected with VDD_LED- interface by a node A4, and node A4 after one resistance R3 of series connection by being grounded;No. 2 pins pass through series connection one capacitor C7 ground connection;No. 3 pins and No. 7 pins directly pass through wired earth, and No. 4 pins and No. 6 pins are connected on the node A3 and node A2 at the both ends of inductance L1 respectively;No. 5 pins then pass through resistance R1 and are wired at node A1;Node A1, node A2 and node A3 are on same circuit lead, and node A1 is connected with VBUS_IR, and node A3 is connected on VDD_LED by diode D1.
Description
Technical field
The utility model relates to a kind of infrared light compensating lamp flow control circuits, belong to security protection appliance applications technical field.
Background technique
There is technology much based on recognition of face currently on the market, iris recognition and In vivo detection have required infrared light filling
Lamp, the working principle diagram of infrared light compensating lamp typically now is as shown in Figure 1, directly using power series resistance, then concatenation J6
(infrared light-emitting diode), then be formed into a loop to GND, the infrared light-emitting diode on J6 shines;But with the variation of temperature
The internal resistance of infrared light-emitting diode on J6 can change, so the equivalent resistance on circuit can also change.Thus
Electric current is caused to change.To which luminous brightness changes.
It therefore is currently on the market essentially all that electricity consumption subject string connecting resistance to realize lights infrared light-emitting diode.With making
It can be showed with time and environment temperature its brightness inconsistent, be increased so as to cause iris recognition or human testing identification difficulty.
Utility model content
The technical problems to be solved in the utility model is the shortcomings that overcoming the prior art, and providing one kind may be implemented accurately to control
System flows through the circuit of infrared light-emitting diode electric current.
In order to solve the above-mentioned technical problem, the utility model provides the following technical solution:
The utility model provides a kind of infrared light compensating lamp flow control circuit, including access LED electroluminescent lamp interface J3 and partial pressure
Circuit U 3;
The both ends of LED electroluminescent lamp interface J3 are separately connected the positive and negative polarities of LED electroluminescent lamp, are respectively as follows: VDD_LED and VDD_
LED-;
Bleeder circuit U3 is the integrated circuit of SGM3749YTD16G model, which is provided with 7 pins, and No. 1 is drawn
Foot is directly connected VDD_LED-, and is divided in the front end that is connected with VDD_LED- interface by a node A4, and node A4 is logical
It is grounded after crossing one resistance R3 of series connection;No. 2 pins pass through series connection one capacitor C7 ground connection;No. 3 pins and No. 7 pins directly pass through conducting wire
Ground connection, No. 4 pins and No. 6 pins are connected on the node A3 and node A2 at the both ends of inductance L1 respectively;No. 5 pins then pass through resistance
R1 is wired at node A1;Node A1, node A2 and node A3 are on same circuit lead, and node A1 and VBUS_IR
It is connected, node A3 is connected on VDD_LED by diode D1.
As a kind of optimal technical scheme of the utility model, one point is connected on the circuit that node A1 is connected with VBUS_IR
Branch circuit, the circuit are grounded by capacitor C1.
As a kind of optimal technical scheme of the utility model, one is connected on the circuit that diode D1 is connected with VDD_LED
Branch circuit, the circuit are grounded by capacitor C2.
The utility model beneficial effect achieved is: the utility model structure is simple, is widely used, and mainly passes through control
System greatly improves iris either In vivo detection efficiency to stablize its luminous intensity by the electric current of infrared light-emitting diode.
Detailed description of the invention
Attached drawing is used to provide a further understanding of the present invention, and constitutes part of specification, practical with this
Novel embodiment is used to explain the utility model together, does not constitute limitations of the present invention.
In the accompanying drawings:
Fig. 1 is the circuit fundamental diagram before the utility model infrared light compensating lamp is improved;
Fig. 2 is circuit fundamental diagram after the utility model infrared light compensating lamp is improved;
Fig. 3 is the circuit fundamental diagram of the utility model bleeder circuit U3.
Specific embodiment
In the description of the present invention, it should be noted that the instructions such as term "vertical", "upper", "lower", "horizontal"
Orientation or positional relationship is to be based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description the utility model and simplification
Description, rather than the device or element of indication or suggestion meaning must have a particular orientation, constructed and grasped with specific orientation
Make, therefore should not be understood as limiting the present invention.
In the description of the present invention, it should also be noted that, unless otherwise clearly defined and limited, term " is set
Set ", " installation ", " connected ", " connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection,
Or it is integrally connected;It can be mechanical connection, be also possible to be electrically connected;It can be directly connected, intermediary can also be passed through
It is indirectly connected, can be the connection inside two elements.It for the ordinary skill in the art, can be according to specific feelings
Condition understands the concrete meaning of above-mentioned term in the present invention.
It is illustrated below in conjunction with preferred embodiment of the attached drawing to the utility model, it should be understood that described herein excellent
It selects embodiment to be only used for describing and explaining the present invention, is not used to limit the utility model.
As Figure 2-3, the utility model provides a kind of infrared light compensating lamp flow control circuit, including access LED electroluminescent lamp connects
Mouth J3 and bleeder circuit U3;
The both ends of LED electroluminescent lamp interface J3 are separately connected the positive and negative polarities of LED electroluminescent lamp, are respectively as follows: VDD_LED and VDD_
LED-;
Bleeder circuit U3 is the integrated circuit of SGM3749YTD16G model, which is provided with 7 pins, and No. 1 is drawn
Foot is directly connected VDD_LED-, and is divided in the front end that is connected with VDD_LED- interface by a node A4, and node A4 is logical
It is grounded after crossing one resistance R3 of series connection;No. 2 pins pass through series connection one capacitor C7 ground connection;No. 3 pins and No. 7 pins directly pass through conducting wire
Ground connection, No. 4 pins and No. 6 pins are connected on the node A3 and node A2 at the both ends of inductance L1 respectively;No. 5 pins then pass through resistance
R1 is wired at node A1;Node A1, node A2 and node A3 are on same circuit lead, and node A1 and VBUS_IR
It is connected, node A3 is connected on VDD_LED by diode D1.
A branch circuit is connected on the circuit that node A1 is connected with VBUS_IR, which is grounded by capacitor C1.
A branch circuit is connected on the circuit that diode D1 is connected with VDD_LED, which is grounded by capacitor C2.
The utility model is in previous experiments, the value of each element are as follows: C1=10uF, C2=10uF, C7=47nF;
R1=10K, R3=1.0K;L1 is model SWPA3015S100MT;The model of D1 is B5819W;U3 is model
SGW3749YTD16G;It is 0.2V that B and bleeder circuit U3 chip interior, which have a 0.2V comparator Reference Control,
It is selected that this belongs to setting for chip, can also select other fixed values by outside setting, is guaranteeing that the place FB voltage is 0.2V, together
When according to circuit SW → D1 → LED → J3 → FB+Rset → GND;The relationship of this partial circuit, can be according to the feedback of the part FB
Equivalent output voltage at SW is adjusted, wherein equivalent output voltage at SW, to guarantee Vfb=0.2V;
Naturally also according to the actual situation, other suitable numerical value are selected, to guarantee that the flow control circuit is answered suitable for other
With place, expand its use scope.
Working principle:
The utility model is mentioned by the electric current of infrared light-emitting diode to stablize its luminous intensity significantly by control
High iris either In vivo detection efficiency, mainly by meeting in our bleeder circuit U3 according to the electronic feedback tune of the part FB
Voltage at section SW flows through the electric current I=Vfb/R3=0.2V/1R=of R3 so that the voltage at FB is maintained at 0.2V in this way
200mA (assuming that R3=1R), the I=100mA if R3=2R.It can be seen that the electric current for flowing through R3 is only related with R3;
VDD_LED is then attached to R3 and FB by J3 connection A4, and R3 other side is to GND;By kirchhoff electric current
Theorem: current phasor in circuit node on any one node and be 0.It is simple to understand to be exactly the size of current flowed on node
Equal to the size of current of outflow;
And in the integrated circuit inside bleeder circuit U3, the amplifier of FB and power source internal connects, by analysis operational amplifier circuit
Void it is disconnected and it is empty it is short known to (void is short: refer in amplifier+and-between voltage it is equal.Void is disconnected to be referred to: flow through+and-between electric current
It is 0A for 0A): the electric current for flowing through FB to chip.The electric current between U3+ and U3- is actually flowed through due to limitation of technique etc.
It is not 0 but the numerical value of uA rank.It is less than the electric current 0.200A that our infrared light-emitting diodes need from far away, it is possible to neglect
Slightly disregard.
Therefore, the electric current for flowing through infrared light-emitting diode J3 is equal to the electric current for flowing through R3.And only have with the size of R3
It closes.
Finally, it should be noted that the above is only the preferred embodiment of the utility model, it is not limited to practical
It is novel, although the utility model is described in detail with reference to the foregoing embodiments, for those skilled in the art,
It is still possible to modify the technical solutions described in the foregoing embodiments, or part of technical characteristic is carried out etc.
With replacement.Within the spirit and principle of the utility model, any modification, equivalent replacement, improvement and so on should all include
It is within the protection scope of the utility model.
Claims (3)
1. a kind of infrared light compensating lamp flow control circuit, which is characterized in that including access LED electroluminescent lamp interface J3 and bleeder circuit
U3;
The both ends of LED electroluminescent lamp interface J3 are separately connected the positive and negative polarities of LED electroluminescent lamp, are respectively as follows: VDD_LED and VDD_
LED-;
Bleeder circuit U3 is the integrated circuit of SGM3749YTD16G model, which is provided with 7 pins, and No. 1 pin is straight
Series connection VDD_LED- is met, and is divided in the front end that is connected with VDD_LED- interface by a node A4, node A4 passes through string
It is grounded after joining a resistance R3;No. 2 pins pass through series connection one capacitor C7 ground connection;No. 3 pins and No. 7 pins are directly connect by conducting wire
Ground, No. 4 pins and No. 6 pins are connected on the node A3 and node A2 at the both ends of inductance L1 respectively;No. 5 pins then pass through resistance R1
It is wired at node A1;Node A1, node A2 and node A3 are on same circuit lead, and node A1 and VBUS_IR phase
Even, node A3 is connected on VDD_LED by diode D1.
2. a kind of infrared light compensating lamp flow control circuit according to claim 1, which is characterized in that node A1 and VBUS_IR phase
A branch circuit is connected on circuit even, which is grounded by capacitor C1.
3. a kind of infrared light compensating lamp flow control circuit according to claim 1, which is characterized in that diode D1 and VDD_LED
A branch circuit is connected on connected circuit, which is grounded by capacitor C2.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CN201820933344.1U CN208353661U (en) | 2018-06-15 | 2018-06-15 | A kind of infrared light compensating lamp flow control circuit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201820933344.1U CN208353661U (en) | 2018-06-15 | 2018-06-15 | A kind of infrared light compensating lamp flow control circuit |
Publications (1)
Publication Number | Publication Date |
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CN208353661U true CN208353661U (en) | 2019-01-08 |
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ID=64884227
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CN201820933344.1U Active CN208353661U (en) | 2018-06-15 | 2018-06-15 | A kind of infrared light compensating lamp flow control circuit |
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CN (1) | CN208353661U (en) |
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2018
- 2018-06-15 CN CN201820933344.1U patent/CN208353661U/en active Active
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