LED light source system

Abstract

The present invention discloses an LED light source system, which mainly includes an MCU controller, a constant current source connected to the MCU controller, an LED constant current dimming module, an LED light source abnormal protection circuit, and an LED light source working state monitoring circuit; the LED constant current dimming module includes a D / A conversion circuit, an analog signal processing circuit, a DC voltage circuit, and an LED constant current circuit connected in sequence, the input end of the DC voltage circuit is connected to the constant current source, the output end is connected to the LED light source working state monitoring circuit, the output end of the LED constant current circuit is connected to the LED light source and the camera strobe module, and the input end is connected to the LED light source abnormal protection circuit. The present invention adopts a DC voltage circuit and an LED constant current circuit to form an LED constant current dimming circuit, has an independent hardware strobe circuit and a parallel light source abnormal protection circuit, can achieve a wide adjustable range of light source brightness, and can be synchronized with the camera in real-time strobe.

Description

Technical Field

[0001] The invention relates to the field of mechanical vision, and in particular to an LED light source system. Background Art

[0002] The core of the machine vision system is image acquisition and processing. All information comes from the image, and the quality of the image itself is extremely critical to the entire vision system. The light source is an important factor affecting the image level of the machine vision system, because it directly affects the quality of the input data and at least 30% of the application effect. Commonly used light sources include LED light sources, halogen lamps (fiber optic light sources), high-frequency fluorescent lamps, etc. LED light sources are widely used in the field of machine vision lighting due to their fast response speed, stable performance, flexible combination, many colors, low power consumption, and long life. The LED light source used in the field of machine vision has higher requirements in terms of its performance and stability, which requires the controller that drives the LED light source to have performance and stability requirements.

[0003] At present, in industrial inspection, constant current stroboscopic LED light source systems generally use high-power LED light sources based on constant lighting to provide light for the camera. In actual operation, in order to obtain images with better signal-to-noise characteristics, it is usually necessary to increase the light intensity of the LED light source to achieve adjustable brightness. However, due to the short exposure time of the camera, the constant lighting mode of the high-power LED light source will directly cause a large amount of electrical energy waste; at the same time, the constant lighting mode directly causes the LED light source to be in a high-temperature heating state for a long time, which can easily lead to a sharp decline in the actual service life of the LED light source.

[0004] In the field of industrial inspection, in order to achieve efficient inspection, the inspection object moves into the camera's inspection field of view, and the camera triggers the light source to light up. At this time, the camera exposes and takes pictures, so the real-time requirement is relatively high. However, the current constant current stroboscopic LED light source basically controls the LED constant current dimming circuit after the camera trigger signal passes through the CPU, and the CPU software processes it to achieve stroboscopic. The software program runs slowly and cannot achieve stroboscopic in real time. In addition, due to the camera's stroboscopic, it is very easy to cause the LED light source to work abnormally, which also causes the LED light source to overheat.

[0005] Therefore, there is an urgent need to provide a new type of LED light source system to solve the above problems. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide an LED light source system, which can realize a wide adjustable range of light source brightness and can perform real-time stroboscopic operation synchronously with a camera.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide an LED light source system, which mainly includes an MCU controller, a constant current source connected to the MCU controller, an LED constant current dimming module, an LED light source abnormality protection circuit, and an LED light source working status monitoring circuit;

[0008] The LED constant current dimming module includes a D / A conversion circuit, an analog signal processing circuit, a DC voltage circuit, and an LED constant current circuit connected in sequence. The input end of the DC voltage circuit is connected to a constant current source, and the output end is connected to an LED light source working status monitoring circuit. The output end of the LED constant current circuit is connected to an LED light source and a camera strobe module, and the input end is connected to an LED light source abnormality protection circuit.

[0009] In a preferred embodiment of the present invention, the DC voltage circuit includes resistors R11-R14, capacitors C2-C6, diodes D3-D4, inductor L1, and a voltage regulating chip U1. The positive electrode of the diode D3 is connected to the resistor R11, and the negative electrode is connected in parallel with the resistors R12-R14 and the 4th pin of the voltage regulating chip U1. The other end of the resistor R14 is connected to the capacitor C2, and the other end of the resistor R11 is connected to the analog signal processing circuit. One end of the inductor L1 is connected to the negative electrode of the diode D4 and the voltage output port of the voltage regulating chip U1, and the other end is connected in parallel with the capacitors C2, C5, C6 and the dimming reference feedback port of the LED constant current dimming circuit. The voltage input port of the voltage regulating chip U1 is connected in parallel with the capacitors C3, C4 and the +24V constant current source.

[0010] In a preferred embodiment of the present invention, the constant current source includes a DC / DC conversion circuit and a DC power input interface, the input end of the DC / DC conversion circuit is connected to the MCU controller, and the output end is connected to the DC power input interface.

[0011] In a preferred embodiment of the present invention, the camera strobe module includes a camera TRIG interface and a TRIG conversion circuit, and the camera TRIG interface is connected to the LED constant current circuit through the TRIG conversion circuit.

[0012] In a preferred embodiment of the present invention, the TRIG conversion circuit includes resistors R5-R10, a diode D2, and a transistor Q2. The positive electrode of the diode D2 is connected to the resistor R7, and the negative electrode is connected to the resistor R9. The other end of the resistor R9 is connected to the base of the transistor Q2. The resistor R10 is connected in parallel between the base and the emitter of the transistor Q2. The collector of the transistor Q2 is connected in parallel with the resistors R5, R6, R8, and the EN port of the LED constant current circuit. The other end of the resistors R5-R7 is connected to the +12VDC voltage.

[0013] In a preferred embodiment of the present invention, the LED light source abnormal protection circuit includes resistors R1-R4, transistor Q1, TVS transient suppression diode D1, and capacitor C1. One end of resistor R2 is connected to the Con_1 pin of the MCU controller and the other end is connected to the base of the transistor Q1. Resistor R4 is connected in parallel between the base and emitter of the transistor Q1. The collector of diode Q1 is connected to the EN port of the LED constant current circuit and resistor R1. The other end of resistor R1 is connected in parallel with resistor R3, capacitor C1, TVS transient suppression diode D1, and AD2 pin of the MCU controller. Resistor R3 and capacitor C1 are connected in parallel to form an RC filter circuit. The other end of the TVS transient suppression diode D1 is connected to a +3.3V power supply.

[0014] In a preferred embodiment of the present invention, the LED constant current circuit includes a resistor R21, a constant current driving chip DD311, and a plurality of light-emitting diodes. The first pin of the constant current driving chip DD311 is connected to the resistor R21, the second pin is connected in series with a plurality of light-emitting diodes, and the other end of the resistor R21 is connected to the voltage output pin V11 of the DC voltage circuit.

[0015] In a preferred embodiment of the present invention, the LED light source controller further includes a communication module connected to the MCU controller, a key circuit, a power-off storage circuit, a digital tube display module, and a working indicator light.

[0016] Furthermore, the communication module adopts a MAX232 serial communication circuit or an RS485 serial communication circuit.

[0017] In order to solve the above technical problems, another technical solution adopted by the present invention is: to provide an LED light source system, which mainly includes an MCU controller, a multi-channel LED light source, a constant current source connected to the MCU controller, a multi-channel parallel LED constant current dimming module, an LED light source abnormality protection circuit, and an LED light source working status monitoring circuit;

[0018] The LED constant current dimming module includes a D / A conversion circuit, an analog signal processing circuit, a DC voltage circuit, and an LED constant current circuit connected in sequence; the input end of the DC voltage circuit is connected to a constant current source, and the output end is connected to an LED light source working state monitoring circuit; the output end of the LED constant current circuit is connected to an LED light source and a camera strobe module, and the input end is connected to an LED light source abnormality protection circuit;

[0019] Multiple LED constant current circuits are connected in parallel, and the multiple LED constant current circuits are connected to one LED light source.

[0020] The beneficial effects of the present invention are:

[0021] (1) The present invention adopts a DC voltage circuit and an LED constant current circuit to form an LED constant current dimming circuit. The DC voltage circuit adopts a voltage linear adjustable type to adjust the constant current source reference to achieve linear adjustment of the LED current, and the consistency of the luminous brightness is better. At the same time, an MCU controller is used to control the D / A output voltage, and then the D / A output voltage range is expanded through an analog signal processing circuit, thereby achieving a wider dimming range of the LED light source, meeting the requirements of industrial equipment for light source brightness adjustment;

[0022] (2) The present invention has an independent hardware strobe circuit, which does not need to be controlled by an MCU controller, has a faster response speed, and achieves ns-level delay. In this way, when the material being tested dynamically passes through the detection point, the camera triggers the signal, the LED light source can be lit in real time, and the camera exposes and images in real time, achieving efficient detection and better real-time synchronization with the camera;

[0023] (3) The present invention has a parallel light source abnormality protection circuit, which realizes protection when the light source is abnormal without affecting the operation of the independent strobe circuit, thereby ensuring the reliable operation of the light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural block diagram of a preferred embodiment of the LED light source system of the present invention;

[0025] Figure 2 is a structural block diagram of another preferred embodiment of the LED light source system;

[0026] Figure 3 is a circuit diagram of the DC voltage circuit;

[0027] Figure 4 is a circuit diagram of the LED constant current circuit;

[0028] Figure 5 is a circuit diagram of the camera strobe circuit;

[0029] Figure 6 is a circuit diagram of the LED light source abnormality protection circuit. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0031] See also Figure 1 , the embodiment of the present invention includes:

[0032] An LED light source system, taking a four-channel LED light source as an example, mainly includes an MCU controller, four LED light sources, a constant current source connected to the MCU controller, a four-channel parallel LED constant current dimming module, an LED light source abnormal protection circuit, and an LED light source working state monitoring circuit; it also includes a communication module connected to the MCU controller, a key circuit, a power-off storage circuit, a digital tube display module, and a four-channel working indicator light. The four-way LED constant current circuits are connected in parallel. The communication module adopts a MAX232 serial communication circuit or an RS485 serial communication circuit. In this embodiment, a MAX232 serial communication circuit is adopted. The digital tube display module includes a digital tube drive circuit connected to the MCU controller and a digital tube four-channel display circuit connected to the digital tube drive circuit. The four-way constant current source dimming module realizes that each light source outputs a set constant current, thereby achieving light stability of the light source output.

[0033] Preferably, the MCU controller adopts a microprocessor STM32F103RBT6, which is small in size and powerful in function. The constant current source includes a DC / DC conversion circuit and a DC power input interface, wherein the input end of the DC / DC conversion circuit is connected to the MCU controller, and the output end is connected to the DC power input interface. The stability of the LED light source system is effectively ensured by the DC supply source.

[0034] Combine the following Figure 2 , take any channel LED light source as an example to explain this LED light source system in detail:

[0035] The LED constant current dimming module includes a D / A conversion circuit, an analog signal processing circuit, a DC voltage circuit, and an LED constant current circuit connected in sequence. The module uses an MCU controller to control the D / A output voltage, and then expands the D / A output voltage range through the analog signal processing circuit, thereby achieving a wider dimming range of the LED light source and meeting the requirements of industrial equipment for light source brightness adjustment. In this embodiment, the analog signal processing circuit uses a four-channel commercial operational amplifier LMV324.

[0036] The input end of the DC voltage circuit is connected to a constant current source, and the output end is connected to a LED light source working state monitoring circuit. Figure 3, the DC voltage circuit includes resistors R11-R14, capacitors C2-C6, diodes D3-D4, inductor L1, and voltage regulator chip U1. The circuit components and their connection relationships are shown in the figure. The positive electrode of diode D3 is connected to resistor R11, and the negative electrode is connected in parallel with resistors R12-R14 and the 4th pin of the voltage regulator chip U1. The other end of resistor R14 is connected to capacitor C2, and the other end of resistor R11 is connected to the analog signal processing circuit. One end of inductor L1 is connected to the negative electrode of diode D4 and the voltage output port of voltage regulator chip U1, and the other end is connected in parallel with capacitors C2, C5, C6 and the dimming reference feedback port of the LED constant current dimming circuit. The voltage input port of voltage regulator chip U1 is connected in parallel with capacitors C3, C4 and +24V constant current source. Preferably, the voltage regulator chip U1 adopts LM2596S.

[0037] The MCU controller outputs an A / D signal. The voltage signal of the A / D is processed by the analog signal processing circuit to generate a voltage signal with an amplified voltage amplitude. The signal is sent to the reference port (pin 4) of the LM2596S and the output voltage V11 for proportional feedback, so that the output voltage V11 is a linear stable voltage with a large voltage range (0-24V). The 0-24V variable voltage is connected to the dimming reference feedback port (pin 1 of DD311) of the LED constant current circuit, so that the LED constant current circuit can control the LED light source in a large range and achieve a suitable stable brightness. The DC voltage circuit uses a voltage linear adjustable type to adjust the constant current source reference to achieve linear adjustment of the LED current, and the brightness consistency of the light is better.

[0038] The output end of the LED constant current circuit is connected to the LED light source and the camera strobe module, and the input end is connected to the LED light source abnormal protection circuit. In addition, one LED light source can also be connected to multiple LED constant current circuits. Each LED light source is composed of several parallel light-emitting diodes, such as 5, 8, 17, etc. The number of light-emitting diodes is not limited. Each LED light source is provided with an interface to connect to the MCU controller. Combined with Figure 4, an LED light source is composed of 8 LED constant current circuits with the same circuit structure. Taking the first LED constant current circuit as an example, the LED constant current circuit includes a resistor R21, a constant current driver chip DD311, and seven light-emitting diodes D11-D17. The first pin of the constant current driver chip DD311 is connected to the resistor R21, the second pin is connected in series with seven light-emitting diodes D17-D11, the third and fourth pins are grounded, and the fifth pin is the ENABLE port. The other end of the resistor R21 is connected to the voltage output pin V11 of the DC voltage circuit. The 8 LED constant current circuits are connected in parallel through the voltage output pin V11, and the voltage reference is continuously adjustable from 0-24V. One LED constant current circuit is controlled by one constant current driver chip to realize one constant current. Multiple identical LED constant current circuits are connected together to form a high-power LED light source to meet the lighting needs of LED high-power light sources. The fifth pins of the multiple constant current driver chips DD311 are connected together to the camera strobe circuit to achieve real-time strobe. The constant current driver chip DD311 has a built-in constant current function and a fast response speed. By using a constant current switch driver chip to enable switch control, the strobe response speed is made faster.

[0039] In practical applications, the LED constant current circuit is designed on a separate light source board, not on the MCU controller circuit board, to facilitate the formation of a high-power LED light source.

[0040] The LED light source system has an independent hardware strobe light circuit, does not need to be controlled by an MCU controller, has a faster response speed, and achieves ns-level delay. In this way, when the material to be tested dynamically passes through the detection point, the camera triggers the signal, the LED light source can be lit in real time, and the camera exposes and images in real time, achieving efficient detection and better real-time synchronization with the camera.

[0041] The camera strobe module includes a camera TRIG interface and a TRIG conversion circuit, and the camera TRIG interface is connected to the LED constant current circuit through the TRIG conversion circuit. Figure 5 , the TRIG conversion circuit includes resistors R5-R10, diode D2, and transistor Q2. The positive electrode of diode D2 is connected to resistor R7, and the negative electrode is connected to resistor R9. The circuit components and their connection relationships are shown in the figure. The other end of resistor R9 is connected to the base of transistor Q2. Resistor R10 is connected in parallel between the base and emitter of transistor Q2. The collector of transistor Q2 is connected in parallel with resistors R5, R6, R8, and the EN port of the LED constant current circuit. The other end of resistors R5-R7 is connected to the +12VDC voltage. The camera TRIG interface outputs a high impedance state or a low level. When it is in a high impedance state, the LED constant current circuit does not work; when it is at a low level, the transistor Q2 is in a non-working state. The +12VDC voltage drives the LED constant current circuit through resistors R5 and R6 to ensure that the LED constant current circuit works normally in real time, thereby realizing real-time strobe synchronization with the camera.

[0042] The LED light source working status monitoring circuit monitors the working status of the light source in real time. When the working time of the light source exceeds the camera exposure time by several times, the MCU controller detects an abnormal signal and sends a signal to the LED light source abnormal protection circuit. An independent stroboscopic mode is adopted to force the LED light source to strobe at a fixed frequency and duty cycle, thereby preventing the LED light source from overheating and ensuring that the LED works in a safe working area.

[0043] Combination Figure 6 The LED light source abnormal protection circuit includes resistors R1-R4, transistor Q1, TVS transient suppression diode D1, and capacitor C1. The circuit components and their connection relationships are shown in the figure. One end of resistor R2 is connected to the Con_1 pin of the MCU controller, and the other end is connected to the base of transistor Q1. Resistor R4 is connected in parallel between the base and emitter of transistor Q1. The collector of diode Q1 is connected to the EN port of the LED constant current circuit and resistor R1. The other end of resistor R1 is connected in parallel with resistor R3, capacitor C1, TVS transient suppression diode D1, and AD2 pin of the MCU controller. Resistor R3 and capacitor C1 are connected in parallel to form an RC filter circuit. The other end of TVS transient suppression diode D1 is connected to a +3.3V power supply. The MCU controller detection port detects the voltage change of AD2. When the LED constant current circuit works for several times longer than the normal strobe time and is in an abnormal working state, AD2 is always at a high level. At this time, the Con_1 pin of the MCU controller outputs a high level, forcing the LED constant current circuit port EN to be pulled low. After a delay, the Con_1 pin is pulled low again to allow the LED constant current circuit to work normally. If the camera strobe circuit or the camera trigger is normal, the circuit does not participate in the action. If the circuit is still in an abnormal state, the LED light source abnormal protection circuit loops to generate a fixed frequency strobe, thereby ensuring that the LED light source does not overheat.

[0044] The LED light source system is equipped with a power-off storage circuit and has a power-off storage function. When it is turned off and then turned on again, it can restore to the last set parameters. At the same time, it has a key circuit and a digital tube display circuit, which can realize the manual interface setting of each light source parameter to achieve the best light distribution effect. Therefore, the light source system is designed with two dimming methods, one is through the communication module, that is, the MCU adjusts each constant current source in real time at 1024 levels to achieve continuous adjustment of the LED light source; the other is through the key circuit, using the key to dim, which is quick and convenient.

[0045] The present invention adopts a DC voltage circuit and an LED constant current circuit to form an LED constant current dimming circuit, which has an independent hardware strobe circuit and a parallel light source abnormality protection circuit, thereby realizing protection when the light source is abnormal without affecting the operation of the independent strobe circuit, thereby ensuring reliable operation of the light source.

[0046] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An LED light source system, characterized in that: It includes an MCU controller, a constant current source connected to the MCU controller, an LED constant current dimming module, an LED light source abnormality protection circuit, and an LED light source working status monitoring circuit; The LED constant current dimming module includes a D / A conversion circuit, an analog signal processing circuit, a DC voltage circuit, and an LED constant current circuit connected in sequence, wherein the input end of the DC voltage circuit is connected to a constant current source, and the output end is connected to an LED light source working state monitoring circuit, the output end of the LED constant current circuit is connected to an LED light source and a camera strobe module, and the input end is connected to an LED light source abnormality protection circuit; The LED constant current circuit includes a resistor R21, a constant current driving chip DD311, and a plurality of light emitting diodes. The first pin of the constant current driving chip DD311 is connected to the resistor R21, the second pin is connected in series with a plurality of light emitting diodes, and the other end of the resistor R21 is connected to the voltage output pin V11 of the DC voltage circuit. The LED light source abnormal protection circuit includes resistors R1-R4, transistor Q1, TVS transient suppression diode D1, and capacitor C1. One end of resistor R2 is connected to the Con 1 pin of the MCU controller and the other end is connected to the base of the transistor Q1. Resistor R4 is connected in parallel between the base and emitter of the transistor Q1. The collector of diode Q1 is connected to the EN port of the LED constant current circuit and resistor R1. The other end of resistor R1 is connected in parallel with resistor R3, capacitor C1, TVS transient suppression diode D1, and AD2 pin of the MCU controller. Resistor R3 and capacitor C1 are connected in parallel to form an RC filtering circuit. The other end of the TVS transient suppression diode D1 is connected to a +3.3V power supply.

2. The LED light source system according to claim 1, characterized in that: The DC voltage circuit includes resistors R11-R14, capacitors C2-C6, diodes D3-D4, inductor L1, and a voltage regulating chip U1. The positive electrode of the diode D3 is connected to the resistor R11, and the negative electrode is connected in parallel with the resistors R12-R14 and the 4th pin of the voltage regulating chip U1. The other end of the resistor R14 is connected to the capacitor C2, and the other end of the resistor R11 is connected to the analog signal processing circuit. One end of the inductor L1 is connected to the negative electrode of the diode D4 and the voltage output port of the voltage regulating chip U1, and the other end is connected in parallel with the capacitors C2, C5, C6 and the dimming reference feedback port of the LED constant current dimming circuit. The voltage input port of the voltage regulating chip U1 is connected in parallel with the capacitors C3, C4 and the +24V constant current source.

3. The LED light source system according to claim 1, characterized in that: The constant current source comprises a DC / DC conversion circuit and a DC power input interface. The input end of the DC / DC conversion circuit is connected to the MCU controller, and the output end is connected to the DC power input interface.

4. The LED light source system according to claim 1, characterized in that: The camera strobe module includes a camera TRIG interface and a TRIG conversion circuit. The camera TRIG interface is connected to an LED constant current circuit via the TRIG conversion circuit.

5. The LED light source system according to claim 4, characterized in that: The TRIG conversion circuit includes resistors R5-R10, a diode D2, and a transistor Q2. The positive electrode of the diode D2 is connected to the resistor R7, and the negative electrode is connected to the resistor R9. The other end of the resistor R9 is connected to the base of the transistor Q2. The resistor R10 is connected in parallel between the base and the emitter of the transistor Q2. The collector of the transistor Q2 is connected in parallel with the resistors R5, R6, R8, and the EN port of the LED constant current circuit. The other end of the resistors R5-R7 is connected to the +12VDC voltage.

6. The LED light source system according to any one of claims 1 to 5, characterized in that: It also includes a communication module connected to the MCU controller, a key circuit, a power-off storage circuit, a digital tube display module, and a working indicator light.

7. The LED light source system according to claim 6, characterized in that: The communication module adopts a MAX232 serial communication circuit or an RS485 serial communication circuit.

8. The LED light source system according to any one of claims 1 to 5, characterized in that: It includes an MCU controller, a multi-channel LED light source, a constant current source connected to the MCU controller, a multi-channel parallel LED constant current dimming module, an LED light source abnormality protection circuit, and an LED light source working status monitoring circuit; The LED constant current dimming module includes a D / A conversion circuit, an analog signal processing circuit, a DC voltage circuit, and an LED constant current circuit connected in sequence; the input end of the DC voltage circuit is connected to a constant current source, and the output end is connected to an LED light source working state monitoring circuit; the output end of the LED constant current circuit is connected to an LED light source and a camera strobe module, and the input end is connected to an LED light source abnormality protection circuit; Multiple LED constant current circuits are connected in parallel, and the multiple LED constant current circuits are connected to one LED light source.

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