CN201051129Y

CN201051129Y - LED polarity self recognition and self switch circuit

Info

Publication number: CN201051129Y
Application number: CN 200720124601
Authority: CN
Inventors: 邹建
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2007-06-28
Filing date: 2007-06-28
Publication date: 2008-04-23
Anticipated expiration: 2017-06-28

Abstract

The utility model relates to an LED polarity self-identifying and self-switching circuit, which separately connects the two poles of the LED in moving contacts of two relays J 1 and J 2, connects permanent closed contacts of the relays J1 and J 2 to be positive direction bias power, and connects permanent opened contacts of the relays J 1 and J 2 to be reverse direction bias power. A voltage picking point A and a control point B of a computer output high and low level are arranged in the circuit, and the LED has the one-way conducting feature of common diodes. When the switch-in polarity of the LED is correct, the LED is conducted, the current flowing over the LED produces 3.2 voltages on a resistance R 1. When the polarity of the LED is in reverse connection, the LED is conducted, the voltage on resistance R 1 is close to 0 V. Via a judge to the voltage on the resistance R 1, people can identify that the switch-in polarity of the LED is correct or not. If in reverse connection, the utility model is capable of automatically adjusting the polarity switching in the circuit to lead the LED to shine regularly, thereby the detecting efficiency is improved, and the error rate is decreased.

Description

The self-identifying of LED polarity, adaptive switched circuit

Technical field

This use is novel to relate to a kind of testing circuit, is specifically related to polarity identification and commutation circuit to LED.

Background technology

LED is entering fields such as illumination, lamp decoration as a kind of new type light source with very fast speed, attracted people's notice with its long-life, low energy consumption, high stability.Before numerous LED productions, the quality check program of a LED element must be arranged, by checking, the quality of LED is screened, by the coupling of parameter, LED is classified.When detecting, must need to make it be in luminance with in the LED place in circuit, then its light, electrical quantity are detected.

LED self is a diode, has unidirectional on state characteristic, so, in place in circuit, certainly exist the matching problem of a polarity, only could guarantee the normally luminous of LED with correct polarity place in circuit, in case polarity connects instead, LED is not irradiative.When detecting, if run into can not be luminous LED, have only two kinds may: LED is bad or polarity has connect instead, so, correctly carry out the detection of LED, must at first to get rid of polarity and connect anti-possibility.

The polarity of LED is come mark by the length of its pin usually, in batch testing, on streamline, detect often, by travelling belt LED is delivered to the detection mouth successively, if by manually discerning polarity according to the length of pin, detection speed must be very low, and artificial cognition is also made mistakes easily.

Summary of the invention

The purpose of this utility model is the deficiency at the prior art existence, the self-identifying of a kind of LED polarity, adaptive switched circuit are proposed, according to the LED electrical characteristics, use COMPUTER DETECTION, not only can discern the polarity of LED automatically, if connect instead, can also adjust the polarity of its place in circuit automatically, make LED normally luminous.

The technical solution of the utility model is as follows:

The self-identifying of a kind of LED polarity, adaptive switched circuit, it is the moving contact that the two poles of the earth of LED is inserted two relay J 1 and J2 respectively, the normally closed contact of relay J 1 and J2 is connected into the forward bias power supply, the normally opened contact of relay J 1 and J2 is connected into the reverse bias power supply, and in circuit, be provided with the reference mark B of voltage acquisition point A and computing machine output high-low level, the normally open contact that voltage acquisition point A point is arranged on relay J 1 and the normally closed interlock of relay J 2 be the contact place mutually, the reference mark B of computing machine output high-low level is by not gate U1A, be connected to the base stage of triode Q1 behind the resistance in series R2, the grounded emitter of triode Q1, the collector circuit of triode Q1 is by resistance R 3, relay J 1 coil L1, relay J 2 coil L2 are in series, by 5 volts of power supply power supplies of direct current.

This circuit can carry out LED polarity identification and switching:

1, polarity identification: utilize LED to have the unidirectional on state characteristic of general-purpose diode, when the polarity that inserts as LED is correct (as shown in Figure 1), LED can conducting, and the electric current (about 20mA) that flows through LED can produce the voltage of 3.2V on resistance R 1; When the LED error-polarity connection, not conducting of LED, the voltage above the R1 is near 0V.By the judgement to voltage above the R1, whether the LED polarity that just can discern current access is correct.

2, polarity is switched: with the voltage on the R1, sent into the A/D capture card of computing machine by the voltage acquisition point A among Fig. 1 and gather, by judging that voltage that A orders whether greater than 1V, if greater than 1V, just illustrates the polarity access correctly; If less than 1V, just illustrate that polarity connects instead (or LED is bad), this computer-chronograph is by the DO output function of A/D card, B point in Fig. 1 is sent high and low level successively, in a circulation, connect anti-and the switch polarity success if the voltage that the A point is gathered, is represented polarity greater than 1V, the voltage of gathering when the A point is still less than 1V, and expression LED is bad.When LED polarity connects instead, when the B point is received the control level that the height of computing machine output changes, triode Q1 incites somebody to action conducting successively and ends, relay coil L1, L2 on the Q1 collector will switch on and cut off the power supply successively, drive the actuating of relay, make J1 and J2 work in normally closed successively and often open, reach the purpose of switch polarity.

As seen, the utility model can be realized automatic identification to LED polarity by above-mentioned simple circuit, if connect instead, can also adjust the polarity of its place in circuit automatically, makes LED normally luminous, can improve detection efficiency, reduces error rate.

Description of drawings

Fig. 1 is that LED polarity is discerned automatically, the circuit theory diagrams of commutation circuit.

Fig. 2 carries out the FB(flow block) that polarity detects and controls by computing machine.

Embodiment

Below in conjunction with accompanying drawing the utility model is elaborated:

The utility model is by the two poles of the earth of LED being inserted the moving contact of two relay J 1 and J2 respectively, the normally closed contact of relay is connected into the forward bias power supply, the normally opened contact of relay is connected into the reverse bias power supply, if relay is failure to actuate, then circuit forms the forward bias current supply circuit, in case the actuating of relay (solenoid energising), the current supply circuit of LED form the reverse bias power supply.Like this, no matter the polarity of LED is just to connect or reversal connection,, can allow its operate as normal by the action of relay.

Referring to Fig. 1, the utmost point of LED links to each other with the moving contact of relay J 1, another utmost point links to each other with the moving contact of relay J 2, the normally closed interlock of relay J 1 is connected with the normally open contact of relay J 2, link to each other with 5 volts of power supplys of direct current simultaneously, the normally open contact of relay J 1 is connected with the normally closed interlock of relay J 2, simultaneously resistance in series R1 ground connection.Voltage acquisition point A point is located at the normally open contact of relay J 1 and the contact mutually of the normally closed interlock of relay J 2.The B point is the reference mark of computing machine output, to transistor circuit input high-low level.The B point is by not gate U1A (74LS04D), be connected to the base stage of triode Q1 (2N5857) behind the resistance in series R2, the grounded emitter of triode Q1, the collector circuit of triode Q1 is by resistance R 3, relay J 1 coil L1, relay J 2 coil L2 are in series, and the collector of triode Q1 is by 5 volts of power supply power supplies of direct current.

Wherein the control principle of computing machine is seen Fig. 2: the initialization of elder generation of system, send high level (being equivalent to relay is failure to actuate), cycle index zero clearing to the B point then; Then gather the voltage that A is ordered, if voltage＞1V illustrates that then polarity is normal; If voltage is less than 1V, cycle index adds 1, and whether judges cycle index greater than 2, if greater than 2, illustrates that then LED is bad; If less than 2, then will control voltage and become non-, send to the B point then, and continue to gather the A point voltage.

Claims

1.LED polarity self-identifying, adaptive switched circuit, it is characterized in that: the two poles of the earth of LED are inserted two relays (J1) and moving contact (J2) respectively, relay (J1) and normally closed contact (J2) are connected into the forward bias power supply, and relay (J1) and normally opened contact (J2) are connected into the reverse bias power supply; Be provided with the reference mark (B) of voltage acquisition point (A) and computing machine output high-low level in the circuit, the normally opened contact that voltage acquisition point (A) point is arranged on relay (J1) and the normally closed interlock of relay (J2) be contact mutually, the reference mark (B) of computing machine output high-low level is by not gate (U1A), be connected to the base stage of triode (Q1) after the resistance in series (R2), the grounded emitter of triode (Q1), the collector circuit of triode (Q1) is to be in series by resistance (R3), relay (J1) coil (L1), relay (J2) coil (L2), by 5 volts of power supply power supplies of direct current.

2. LED polarity according to claim 1 self-identifying, adaptive switched circuit is characterized in that: the normally closed contact of described relay (J1) is connected with the normally opened contact of relay (J2), links to each other with 5 volts of power supplys of direct current simultaneously; The normally opened contact of relay (J1) is connected with the normally closed contact of relay (J2), simultaneously resistance in series (R1) ground connection.