CN202713752U

CN202713752U - Simple LED display module testing circuit

Info

Publication number: CN202713752U
Application number: CN 201220337378
Authority: CN
Inventors: 陈虎; 陈志伟
Original assignee: ECU ELECTRONICS INDUSTRIAL Co Ltd
Current assignee: ECU ELECTRONICS INDUSTRIAL Co Ltd
Priority date: 2012-07-12
Filing date: 2012-07-12
Publication date: 2013-01-30
Anticipated expiration: 2022-07-12

Abstract

The utility model relates to a simple LED display module testing circuit, which comprises a constant current source circuit. The constant current source circuit is connected with the cathode of an LED display module to be tested. A pulse generation circuit is connected with the anode of the LED display module to be tested through a switch circuit. A constant voltage source supplies power to the pulse generation circuit and the switch circuit. By adopting the pulse generation circuit, all the LEDs can be simultaneously turned on by only setting the frequency of pulse signals over 36 Hz at which a naked eye is incapable of distinguishing. One single constant current source circuit is adopted for supplying power to the LED display module to be tested. All LEDs in each area of the LED display module to be tested are accessed to a single constant current source. In this way, the current flowing through each LED is ensured to be a fixed value. A tester is then enabled to conveniently rapidly find out a black spot and judge whether there is an uneven lighting phenomenon existing in the LED display module to be tested.

Description

A kind of simple and easy LED display module test circuit

Technical field

The utility model relates to a kind of test circuit, especially a kind of simple and easy LED display module test circuit.

Background technology

Along with to strictly the considering of the energy and cost, the charactron that is widely used in the household electrical appliances display floater is eliminated gradually, the substitute is signifying green, efficient light-emitting diode (LED).These LED particles or and or be series at circuit, as shown in Figure 1, reach again the display effect of special pattern by software control.

LED is no doubt green, efficient, and whether a difficult problem is but how manufacturer lights LED according to the parameter of setting, thereby judge blind spot and check luminous even.LED needs constant current to drive, and its brightness determines by the electric current by himself, yet what obtain easily in the laboratory is source of stable pressure, so common way is the source of stable pressure series resistance.For circuit shown in Figure 1, ABCDEFGH can be connected as negative pole, 12345678 connect as anodal after the series resistance respectively.Because the parameter of LED is variant, and arrangement mode is different, and 1 district is two LED particle series connection, only there is a LED particle in 2 districts, and have in 1 district series resistance is arranged simultaneously, if want like this to obtain stable constant-current source, just need constantly to adjust the resistance of each district institute crosstalk resistance, be unfavorable for realizing.Its control procedure can be with reference to Fig. 2.

Moreover supposition can guarantee the electric current that obtains to envision by the adjustment of complexity, for above-mentioned circuit, and take 1 district as example, because different diode drops is different, (cause the reason of this phenomenon to have two: one, foozle, the LED wafer is impossible in full accord; Other reason is that the LED particle in 1 district may exist color distortion, be red such as 1A, 1B is green), the electric current that is added in like this 1 district just fully mean allocation on each LED particle, the result who causes is that brightness is inconsistent or can't get a desired effect, and makes troubles for manufacturing or the check of product.

The utility model content

The purpose of this utility model is to provide a kind of and LED particle in the LED display module can be lighted simultaneously, and the electric current that guarantees to flow through each LED particle is the simple and easy LED display module test circuit of the numerical value of customer requirements.

For achieving the above object, the utility model has adopted following technical scheme: a kind of simple and easy LED display module test circuit, comprise constant-current source circuit, constant-current source circuit links to each other with the negative pole of LED display module to be tested, pulse generating circuit links to each other with the positive pole of LED display module to be tested by switching circuit, and constant voltage power supply circuit is to pulse generating circuit and switching circuit power supply.

As shown from the above technical solution, the utility model adopts pulse generating circuit, and only need more than the frequency (36Hz) that human eye can't be differentiated, can be lighted the set of frequency of pulse signal with all LED " simultaneously "; Adopt single constant-current source circuit that LED display module to be tested is powered, each all LED in zone of LED display module to be tested all accesses single constant-current source, the electric current of each LED is fixed value thereby assurance is flowed through, and is convenient to the tester and finds out rapidly blind spot and judge whether LED display module to be tested exists the phenomenon of non-uniform light.

Description of drawings

Fig. 1 is LED display module schematic diagram for example;

Fig. 2 is the source of stable pressure series resistance test circuit that LED display module shown in Figure 1 is tested;

Fig. 3,4,5, the 6th, the circuit theory diagrams of constant-current source circuit, pulse generating circuit, switching circuit, constant voltage power supply circuit in the utility model.

Embodiment

A kind of simple and easy LED display module test circuit, comprise constant-current source circuit 1, constant-current source circuit 1 links to each other with the negative pole of LED display module 5 to be tested, pulse generating circuit 2 links to each other with the positive pole of LED display module 5 to be tested by switching circuit 3, constant voltage power supply circuit 4 is to pulse generating circuit 2 and switching circuit 3 power supplies, as shown in Figure 5.

As shown in Figure 3, described constant-current source circuit 1 comprises diode D1, the negative electrode of diode D1 links to each other with the anode of diode D2, the negative electrode of diode D2 links to each other with an end of resistance R 2, the base stage of triode Q1 respectively, the equal ground connection of the collector electrode of the other end of resistance R 2, triode Q1, the emitter of triode Q1 links to each other with an end of resistance R 1, the negative pole of the LED display module 5 of reception test after the other end of resistance R 1 links to each other with the anode of diode D1.Wherein, the size of the electric current of constant-current source circuit 1 output can realize by the resistance of regulating resistance R1.

As shown in Figure 4, described pulse generating circuit 2 comprises counter U1, it is the 8th years old, 12 pin ground connection, it is the 9th years old, 10,11 pins respectively with capacitor C 4, resistance R 22, one end of resistance R 21 links to each other, capacitor C 4, resistance R 22, the other end of resistance R 21 is in parallel, 4 of counter U1,5,6,7 pins respectively with the A of decoder U2, B, C, the D pin links to each other, the output of described three terminal regulator U3 respectively with the 16th pin of counter U1, the VCC pin of decoder U2 links to each other, the 1st of decoder U2,2,3,4,5,6,7,9,10,11 pins link to each other with the end of resistance R 3～R12 respectively, the other end of resistance R 3～R12 links to each other with the base stage of triode Q2～Q11 respectively, the grounded emitter of triode Q2～Q11, the collector electrode of triode Q2～Q11 links to each other with the input of switching circuit 3.

As shown in Figure 6, described constant voltage power supply circuit 4 comprises three terminal regulator U3, the input termination constant pressure source VCC of three terminal regulator U3, and the output of three terminal regulator U3 links to each other with switching circuit 3 with pulse generating circuit 2 respectively.Constant pressure source VCC provide input voltage, output+5V direct current is for counter U1 and decoder U2 after stable through three terminal regulator U3, the alternate conduction signal driver triode Q2 that decoder U2 sends～Q11 alternate conduction, to produce one group of with it anti-phase pulse voltage at a～j lead end like this, this pulse voltage will be for driving switch circuit 3.

As shown in Figure 5, described switching circuit 3 comprises triode Q12, the output of pulse generating circuit 2 links to each other with the base stage of triode Q12 by resistance R 13, the collector electrode of triode Q12 connects the output of described three terminal regulator U3 by resistance R 13, and the emitter of triode Q12 links to each other with the positive pole of LED display module 5 to be tested.The pulse signal that switching circuit 3 utilizes pulse generating circuit 2 to send is controlled turning on and off of triode Q12.

When test, constant-current source circuit 1 is accessed respectively negative wire end A, B, C, D, E, F, G, the H of LED display module 5 to be tested, the

positive wire end

1,2,3,4,5,6,7,8 of LED display module 5 to be tested is connected with switching circuit 3 respectively, another level of all switching circuits 3, namely the collector electrode of triode Q12 meets source of stable pressure VCC.

After the circuit connection, the switching circuit 3 that the

positive wire end

1,2,3,4,5,6,7,8 of LED display module 5 to be tested connects will be open-minded in turn, each regional LED of LED display module 5 to be tested also will light in turn, the set of frequency of pulse signal a, the b that only pulse generating circuit 2 need be sent, c, d, e, f, g, h, l, j can be lighted all LED " simultaneously " more than the frequency (36Hz) that human eye can't be differentiated.Because each all LED in zone all accesses single constant-current source circuit 1, thereby the electric current of each LED that guaranteed to flow through is fixed value, is convenient to the tester and finds out rapidly blind spot and judge whether LED display module to be tested 5 exists the phenomenon of non-uniform light.

Claims

1. simple and easy LED display module test circuit, it is characterized in that: comprise constant-current source circuit (1), constant-current source circuit (1) links to each other with the negative pole of LED display module (5) to be tested, pulse generating circuit (2) links to each other with the positive pole of LED display module (5) to be tested by switching circuit (3), and constant voltage power supply circuit (4) is powered to pulse generating circuit (2) and switching circuit (3).

2. simple and easy LED display module test circuit according to claim 1, it is characterized in that: described constant-current source circuit (1) comprises diode D1, the negative electrode of diode D1 links to each other with the anode of diode D2, the negative electrode of diode D2 links to each other with an end of resistance R 2, the base stage of triode Q1 respectively, the equal ground connection of the collector electrode of the other end of resistance R 2, triode Q1, the emitter of triode Q1 links to each other with an end of resistance R 1, the negative pole of the LED display module (5) of reception test after the other end of resistance R 1 links to each other with the anode of diode D1.

3. simple and easy LED display module test circuit according to claim 1, it is characterized in that: described constant voltage power supply circuit (4) comprises three terminal regulator U3, the input termination constant pressure source VCC of three terminal regulator U3, the output of three terminal regulator U3 link to each other with switching circuit (3) with pulse generating circuit (2) respectively.

4. simple and easy LED display module test circuit according to claim 2, it is characterized in that: described pulse generating circuit (2) comprises counter U1, it is the 8th years old, 12 pin ground connection, it is the 9th years old, 10,11 pins respectively with capacitor C 4, resistance R 22, one end of resistance R 21 links to each other, capacitor C 4, resistance R 22, the other end of resistance R 21 is in parallel, 4 of counter U1,5,6,7 pins respectively with the A of decoder U2, B, C, the D pin links to each other, the output of described three terminal regulator U3 respectively with the 16th pin of counter U1, the VCC pin of decoder U2 links to each other, the 1st of decoder U2,2,3,4,5,6,7,9,10,11 pins link to each other with the end of resistance R 3～R12 respectively, the other end of resistance R 3～R12 links to each other with the base stage of triode Q2～Q11 respectively, the grounded emitter of triode Q2～Q11, the collector electrode of triode Q2～Q11 links to each other with the input of switching circuit (3).

5. simple and easy LED display module test circuit according to claim 3, it is characterized in that: described switching circuit (3) comprises triode Q12, the output of pulse generating circuit (2) links to each other with the base stage of triode Q12 by resistance R 13, the collector electrode of triode Q12 connects the output of described three terminal regulator U3 by resistance R 13, and the emitter of triode Q12 links to each other with the positive pole of LED display module (5) to be tested.