Light source voltage adjustable constant current control system based on machine vision

Abstract

The invention provides a light source voltage adjustable constant current control system based on machine vision, which is used for controlling a light source and comprises a power supply; the voltage reduction circuit is used for reducing the voltage output by the power supply and is provided with a plurality of output ends so as to output different voltages; the constant-current control circuit is connected with a part of output ends of the step-down circuit and is used for performing constant-current control on the light source; the ADC circuit is connected with a part of the output end of the step-down circuit and is used for adjusting the current required by the light source controlled by the constant-current control circuit; and the controller is connected with a part of output ends of the step-down circuit and can control the step-down circuit.

Description

Technical Field

[0001] The invention relates to the field of machine vision, and in particular to a light source voltage-adjustable constant current control system based on machine vision. Background Art

[0002] In the field of machine vision, when shooting with a camera, no light source is needed for supplementary lighting. The light source is controlled by a controller when working, and different light sources have different powers, which requires a different controller for each light source, which obviously increases the cost of use. Summary of the invention

[0003] The main purpose of the present invention is to provide a light source voltage-adjustable constant current control system based on machine vision, which can be applicable to light sources of different powers.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is: a light source voltage adjustable constant current control system based on machine vision, which is used to control the light source, including:

[0005] power supply;

[0006] A step-down circuit, used for stepping down the voltage output by the power supply and having multiple output terminals to output different voltages;

[0007] A constant current control circuit, connected to a part of the output end of the step-down circuit, for performing constant current control on the light source;

[0008] An ADC circuit is connected to a part of the output end of the step-down circuit and is used to adjust the current required by the light source controlled by the constant current control circuit;

[0009] A controller connected to a part of the output end of the step-down circuit and capable of controlling the step-down circuit;

[0010] It is characterized in that the step-down circuit includes a first step-down circuit, a second step-down circuit and a third step-down circuit, the first step-down circuit is electrically connected to the power supply and has a first output end for outputting 12V and a second output end for outputting 5V, the third step-down circuit has a first input end for inputting 12V, a second input end for inputting 5V and a third output end VCC1, the third step-down circuit is electrically connected to the controller at the same time, the first input end is electrically connected to the first output end, the second input end is electrically connected to the second output end, the controller can control the third step-down circuit to output 12V or 5V voltage from the third output end VCC1, the second step-down circuit has a third input end and a fourth output end, and the third input end is electrically connected to the third output end.

[0011] Preferably, the third step-down circuit comprises a transistor Q5 and a MOS transistor Q6, wherein the MOS transistor Q6 is a PMOS transistor, a source S of the MOS transistor Q6 is connected to the first input terminal through a first line, and a drain D of the MOS transistor Q6 is connected to the third output terminal through a second line; the transistor Q5 is an NPN type, a collector C of the transistor Q5 is connected to the first line through a third line, a resistor R22 and a resistor R23 are connected in series on the third line, and a gate G of the MOS transistor Q6 is connected to a portion of the third line located between the resistor R22 and the resistor R23; a base b of the transistor Q5 is electrically connected to the controller, an emitter e of the transistor Q5 is grounded, a fifth line is connected to the second line, the fifth line is connected to the second input terminal, a diode D1 is provided on the fifth line, and the diode D1 is configured to make the fifth line unidirectionally conductive from the second input terminal to the second line; the controller can control the conduction and disconnection of the transistor Q5 by outputting a voltage to the fourth line.

[0012] Preferably, the constant current control circuit includes an operational amplifier U3B, a MOS tube Q1, a MOS tube Q2, and a MOS tube Q3, wherein the MOS tube Q1, the MOS tube Q2, and the MOS tube Q3 are all PMOS tubes, the positive power supply terminal of the operational amplifier U3B is connected to the third output terminal, the negative power supply terminal is grounded, the output terminal is respectively connected to the gates D of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 through a sixth line, the source electrodes S of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 are all connected to the negative terminal of the wiring terminal P1, the light source is mounted on the wiring terminal P1, the positive terminal of the wiring terminal P1 is electrically connected to the power supply, the drain electrodes D of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 are connected to a sampling resistor through a tenth line, the other end of the sampling resistor is grounded, the tenth line is connected to the negative input terminal of the operational amplifier U3B through the seventh line, and the positive input terminal of the operational amplifier U3B is connected to the ADC circuit.

[0013] Preferably, the constant current control circuit also includes an eighth circuit and a transistor Q4, one end of the eighth circuit is connected to the gates of the MOS transistors Q1, Q2, and Q3, and the other end is connected to the collector c of the transistor Q4, the emitter e of the transistor Q4 is grounded, and the base of the transistor Q4 is connected to the controller through a ninth circuit, and the controller can transmit a voltage signal to the base of the transistor Q4.

[0014] Preferably, a detection circuit is also included, and the detection circuit is used to detect the identification resistance of the light source, and the power of the corresponding light source is judged by the identification resistance, so that the corresponding output power of the control system can be adjusted to meet the needs of the current light source. Setting the identification resistance on the light source is a commonly used setting in this field and will not be described in detail. The detection circuit includes a terminal P4 and an operational amplifier U7A for connecting the identification resistance, one end of the terminal P4 is connected to the power supply, and the other end is grounded through the eleventh line. A resistor R30 is arranged on the eleventh line, and the part of the eleventh line located at the resistor R30 and the terminal P4 is connected to the positive input terminal of the operational amplifier U7A through the twelfth line, the output terminal of the operational amplifier U7A is connected to its negative input terminal and is simultaneously connected to the controller, the positive power supply terminal of the operational amplifier U7A is connected to the fourth output terminal, and the negative power supply terminal of the operational amplifier U7A is grounded.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The light source control system of the present invention can realize constant current control of the light source and can adjust the magnitude of the current controlled by the constant current control circuit, thereby being applicable to light sources of different powers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is the first step-down circuit;

[0018] Figure 2 It is the second step-down circuit;

[0019] Figure 3 It is the third step-down circuit;

[0020] Figure 4 It is the ADC circuit;

[0021] Figure 5 It is a constant current control circuit;

[0022] Figure 6 It is a detection circuit;

[0023] Figure 7 Here is the pinout diagram for the controller. DETAILED DESCRIPTION

[0024] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0025] A light source voltage adjustable constant current control system based on machine vision, used for controlling the light source, includes a power supply, a step-down circuit, an ADC circuit, a constant current control circuit, and a controller. The step-down circuit includes a first step-down circuit, a second step-down circuit, and a third step-down circuit. The first step-down circuit is electrically connected to the power supply and has a first output terminal that outputs 12V and a second output terminal that outputs 5V. The third step-down circuit has a first input terminal that inputs 12V, a second input terminal that inputs 5V, and a third output terminal VCC1. The third step-down circuit is electrically connected to the controller at the same time, the first input terminal is electrically connected to the first output terminal, the second input terminal is electrically connected to the second output terminal, the controller can control the third step-down circuit to output 12V or 5V voltage from the third output terminal VCC1, the second step-down circuit has a third input terminal VCC1 and a fourth output terminal that outputs 3.3V, and the third input terminal VCC1 is electrically connected to the third output terminal VCC1. The first step-down circuit and the second step-down circuit both adopt the existing technology.

[0026] The third step-down circuit includes a transistor Q5 and a MOS transistor Q6, wherein the MOS transistor Q6 is a PMOS transistor. The source S of the MOS transistor Q6 is connected to the first input terminal through the first line 1, and the drain D of the MOS transistor Q6 is connected to the second line 2 and connected to the third output terminal through the second line 2. The transistor Q5 is an NPN type, and the collector C of the transistor Q5 is connected to the first line 1 through the third line 3, and the resistor R22 and the resistor R23 are connected in series on the third line 3, and the gate G of the MOS transistor Q6 is connected to the part of the third line 3 located between the resistor R22 and the resistor R23. The base b of the transistor Q5 is electrically connected to the controller, and the emitter e of the transistor Q5 is grounded. The fifth line 5 is connected to the second line 2, and the fifth line 5 is connected to the second input terminal. A diode D1 is arranged on the fifth line 5, and the diode D1 is configured to make the fifth line 5 unidirectionally connected from the second input terminal to the second line 2. The controller can control the conduction and disconnection of the transistor Q5 by outputting a voltage to the fourth line 4. When the transistor Q5 is turned on, the third line 3 is turned on, and the voltage input from the first input terminal passes through the resistor R23 and the resistor R22. At the same time, the voltage acting on the resistor R22 will act on the gate G of the MOS transistor Q6, so that the MOS transistor Q6 is turned on, and the first line 1 is connected to the second line 2. At this time, the third output terminal outputs a voltage of 12V. When the controller controls the transistor Q5 to be disconnected, the third line 3 is not turned on, the voltage of the gate D of the MOS transistor Q6 is 0, the MOS transistor Q6 is disconnected, and the 12V voltage input from the first input terminal cannot reach the third output terminal VCC1. The third output terminal VCC1 outputs the 5V voltage input from the second input terminal.

[0027] The ADC circuit is used to provide a variable voltage for the constant current circuit, thereby adjusting the brightness of the light source. The ADC circuit has a fourth input terminal and a fifth output terminal, which are used to connect to the fourth output terminal of the second step-down circuit. The fifth output terminal can output different voltages. The ADC circuit specifically adopts the existing technology.

[0028] The constant current control circuit includes an operational amplifier U3B, a MOS tube Q1, a MOS tube Q2, and a MOS tube Q3. The MOS tube Q1, the MOS tube Q2, and the MOS tube Q3 are all PMOS tubes. The positive power supply terminal of the operational amplifier U3B is connected to the third output terminal, the negative power supply terminal is grounded, and the output terminal is respectively connected to the gates D of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 through the sixth line 6. The source electrodes S of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 are all connected to the negative terminal LED- of the wiring terminal P1. The light source is installed on the wiring terminal P1, and the positive terminal of the wiring terminal P1 is electrically connected to the power supply. The drain electrodes D of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 are connected to a sampling resistor through a tenth line 10. The sampling resistor is resistors R8 to R19 arranged in parallel, and the other ends of the resistors R8 to R19 are grounded. The tenth line 10 is connected to the negative input terminal of the operational amplifier U3B through the seventh line 7, and the positive input terminal of the operational amplifier U3B is connected to the fifth output terminal of the ADC circuit. The principle of constant current control is as follows: since the seventh line 7 introduces the voltage of the sampling resistor into the negative input terminal of the operational amplifier U3B, a negative feedback is formed. Through the negative feedback, the voltage of the negative input terminal can be the same as the voltage of the positive input terminal, that is, when the voltage of the positive input terminal is fixed, the voltage of the negative input terminal is also fixed, the voltage on the sampling resistor is also fixed, and then the current passing through the sampling resistor is also fixed, thereby realizing constant current control. When the current needs to be changed according to different needs, only the voltage of the positive input terminal needs to be changed.

[0029] The constant current control circuit also includes an eighth line 8 and a transistor Q4, one end of the eighth line 8 is connected to the gates of the MOS transistors Q1, Q2 and Q3, and the other end is connected to the collector c of the transistor Q4, the emitter e of the transistor Q4 is grounded, and the base of the transistor Q4 is connected to the controller through a ninth line 9, and the controller can transmit a voltage signal to the base of the transistor Q4. When the transistor Q4 is turned on, the eighth line 8 is grounded, so that the gate voltages of the MOS transistors Q1, Q2 and Q3 are 0, and at this time, the MOS transistors Q1, Q2 and Q3 are disconnected, thereby realizing the turning off of the light source.

[0030] The system also includes a detection circuit, which is used to detect the identification resistance of the light source, and the power of the corresponding light source is judged by the identification resistance, so as to adjust the corresponding output power of the control system to meet the needs of the current light source. Setting the identification resistance on the light source is a commonly used setting in this field and will not be described in detail. The detection circuit includes a terminal P4 and an operational amplifier U7A for connecting the identification resistance, one end of the terminal P4 is connected to the power supply, and the other end is grounded through the eleventh line 11, and a resistor R30 is arranged on the eleventh line 11, and the part of the eleventh line 11 located at the resistor R30 and the terminal P4 is connected to the positive input terminal of the operational amplifier U7A through the twelfth line 12, and the output terminal of the operational amplifier U7A is connected to its negative input terminal and is connected to the controller at the same time, and the positive power supply terminal of the operational amplifier U7A is connected to the fourth output terminal, and the negative power supply terminal of the operational amplifier U7A is grounded. The resistor R30 is used as a sampling resistor. The controller can calculate the size of the identification resistor in combination with the power supply voltage and the voltage signal collected by the sampling resistor, and then can obtain the power of the light source, and then can obtain the corresponding current according to the obtained power, and then adjust the input voltage of the positive input terminal of the operational amplifier U3B to meet the constant current control of the current light source. The input voltage of the positive input terminal of the operational amplifier U3B is achieved by adjusting the output voltage of the ADC circuit, which can be automatically adjusted by the controller or manually operated by the corresponding control knob. The specific adjustment principle is the existing technology.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A light source voltage adjustable constant current control system based on machine vision, used to control the light source, comprising: power supply; A step-down circuit, used for stepping down the voltage output by the power supply and having multiple output terminals to output different voltages; A constant current control circuit, connected to a part of the output end of the step-down circuit, for performing constant current control on the light source; An ADC circuit is connected to a part of the output end of the step-down circuit and is used to adjust the current required by the light source controlled by the constant current control circuit; A controller connected to a part of the output end of the step-down circuit and capable of controlling the step-down circuit; It is characterized in that the step-down circuit includes a first step-down circuit, a second step-down circuit and a third step-down circuit, the first step-down circuit is electrically connected to the power supply and has a first output end for outputting 12V and a second output end for outputting 5V, the third step-down circuit has a first input end for inputting 12V, a second input end for inputting 5V and a third output end VCC1, the third step-down circuit is electrically connected to the controller at the same time, the first input end is electrically connected to the first output end, the second input end is electrically connected to the second output end, the controller can control the third step-down circuit to output 12V or 5V voltage from the third output end VCC1, the second step-down circuit has a third input end and a fourth output end, and the third input end is electrically connected to the third output end.

2. According to the machine vision-based light source voltage adjustable constant current control system according to claim 1, it is characterized in that: The third step-down circuit includes a transistor Q5 and a MOS transistor Q6. The MOS transistor Q6 is a PMOS transistor. The source S of the MOS transistor Q6 is connected to the first input terminal through the first line, and the drain D of the MOS transistor Q6 is connected to the third output terminal through the second line. The transistor Q5 is an NPN type. The collector C of the transistor Q5 is connected to the first line through the third line. The resistor R22 and the resistor R23 are connected in series on the third line. The gate G of the MOS transistor Q6 is connected to a portion of the third line located between the resistor R22 and the resistor R23. The base b of the transistor Q5 is electrically connected to the controller. The emitter e of the transistor Q5 is grounded. The fifth line is connected to the second line. The fifth line is connected to the second input terminal. A diode D1 is arranged on the fifth line. The diode D1 is configured to make the fifth line unidirectionally conductive from the second input terminal to the second line. The controller can control the conduction and disconnection of the transistor Q5 by outputting a voltage to the fourth line.

3. The light source voltage adjustable constant current control system based on machine vision according to claim 2, characterized in that: The constant current control circuit includes an operational amplifier U3B, a MOS tube Q1, a MOS tube Q2, and a MOS tube Q3. The MOS tube Q1, the MOS tube Q2, and the MOS tube Q3 are all PMOS tubes. The positive power supply terminal of the operational amplifier U3B is connected to the third output terminal, the negative power supply terminal is grounded, the output terminal is respectively connected to the gates D of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 through the sixth line, the source electrodes S of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 are all connected to the negative terminal of the wiring terminal P1, the light source is installed on the wiring terminal P1, the positive terminal of the wiring terminal P1 is electrically connected to the power supply, the drain electrodes D of the MOS tubes Q1, the MOS tube Q2, and the MOS tube Q3 are connected to the sampling resistor through the tenth line, the other end of the sampling resistor is grounded, the tenth line is connected to the negative input terminal of the operational amplifier U3B through the seventh line, and the positive input terminal of the operational amplifier U3B is connected to the ADC circuit.

4. The light source voltage adjustable constant current control system based on machine vision according to claim 3, characterized in that: The constant current control circuit also includes an eighth line and a transistor Q4, one end of the eighth line is connected to the gates of the MOS transistors Q1, Q2, and Q3, and the other end is connected to the collector c of the transistor Q4, the emitter e of the transistor Q4 is grounded, and the base of the transistor Q4 is connected to the controller through a ninth line, and the controller can transmit a voltage signal to the base of the transistor Q4.

5. The light source voltage adjustable constant current control system based on machine vision according to claim 4, characterized in that: It also includes a detection circuit, which is used to detect the identification resistance of the light source, and the power of the corresponding light source is judged by the identification resistance, so as to adjust the corresponding output power of the control system to meet the needs of the current light source. Setting the identification resistance on the light source is a commonly used setting in this field and will not be described in detail. The detection circuit includes a terminal P4 and an operational amplifier U7A for connecting the identification resistance, one end of the terminal P4 is connected to the power supply, and the other end is grounded through the eleventh line, and a resistor R30 is arranged on the eleventh line, and the part of the eleventh line located at the resistor R30 and the terminal P4 is connected to the positive input terminal of the operational amplifier U7A through the twelfth line, the output terminal of the operational amplifier U7A is connected to its negative input terminal and is simultaneously connected to the controller, the positive power supply terminal of the operational amplifier U7A is connected to the fourth output terminal, and the negative power supply terminal of the operational amplifier U7A is grounded.

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