Light source control system for machine vision

Abstract

The invention discloses a light source control system for machine vision. The light source control system comprises a controller; the control circuit comprises an MOS tube Q5, the MOS tube Q5 is an N-type MOS tube, a grid electrode G of the MOS tube Q5 is connected with the controller through a first circuit, a drain electrode D of the MOS tube Q5 is connected with one wiring end of a wiring terminal P6 through a third circuit, the other wiring end of the wiring terminal is connected with the output end of the power supply, and the light source is installed on the wiring terminal; the source electrode of the MOS tube Q5 is grounded through a fourth line; and the controller can output voltage through the first line so as to control the on / off of the MOS tube Q5 and further control the on / off of the light source.

Description

Technical Field

[0001] The present invention relates to the field of machine vision, and in particular to a light source control system for machine vision. Background Art

[0002] In industry, machine vision is often used to inspect workpieces during processing. During inspection, light sources and cameras are used to capture the required images. When shooting, it is very important to control the light source. In many cases, the light source is only turned on when shooting and turned off when shooting ends. However, since the workpieces move quickly on the assembly line, fast switching is required. At the same time, fast switching may occasionally cause the current on the line to be too large or too small. When the current is too large, if it is not turned off in time, it will cause damage to the light source. When the current is too small, although it will not cause damage to the light source, it will also cause energy waste. Therefore, how to control the switch of the light source and how to protect the light source are particularly important. Summary of the invention

[0003] The main purpose of the present invention is to provide a light source control system for machine vision, which can realize the switching of the light source by utilizing a relatively small voltage, and can also automatically cut off the power when the current of the light source is too large or too small.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a light source control system for machine vision, comprising:

[0005] Controller;

[0006] The control circuit comprises a MOS tube Q5, wherein the MOS tube Q5 is an N-type MOS tube, a gate G of the MOS tube Q5 is connected to a controller via a first line, a drain D of the MOS tube Q5 is connected to one terminal of a wiring terminal P6 via a third line, another terminal of the wiring terminal is connected to an output end of a power supply, and the light source is mounted on the wiring terminal; a source of the MOS tube Q5 is grounded via a fourth line 4; and the controller can output a voltage via the first line and thus can control the conduction or disconnection of the MOS tube Q5, thereby controlling the switch of the light source.

[0007] Preferably, the control circuit further includes a second circuit, one end of the second circuit is connected to the output end of the power supply, and the other end is connected to the third circuit, and a resistor R21 is arranged on the second circuit.

[0008] Preferably, the control circuit also includes a resistor R28 and a fifth circuit arranged on a fourth circuit, one end of the fifth circuit is connected to a portion of the fourth circuit located between the MOS tube Q5 and the resistor R28, and the other end of the fifth circuit is connected to a controller, and the controller can obtain the voltage on the resistor R28, and then calculate the current of the light source through the voltage and the resistance value of the resistor R28. When the current passing through the light source is too large or too small, the controller can control the MOS tube Q5 to turn off.

[0009] Preferably, a resistor R27 is provided on the fifth circuit, and the control circuit further includes a sixth circuit, one end of the sixth circuit is connected to a side of the fifth circuit located downstream of the resistor R27, and the other end is grounded, and a capacitor C16 is provided on the sixth circuit, and the resistor R27 and the capacitor C16 form an RC filtering circuit.

[0010] Preferably, the control circuit also includes a seventh circuit, one end of the seventh circuit is connected to one end of the fifth circuit connected to the controller, and the other end is grounded, and a Zener diode D8 is arranged on the seventh circuit. When the Zener diode D8 is not broken down, the Zener diode D8 makes the seventh circuit unidirectionally conductive in the direction from the ground end toward the fifth circuit.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1) The present invention uses a controller to control the switch of the MOS tube to control the switch of the light source, and uses a relatively small voltage to control the switch of the light source; at the same time, the controller can obtain the current passing through the circuit of the light source in real time, and timely control the switch of the light source according to the magnitude of the current;

[0013] 2) The present invention can be powered by external devices such as mobile phones and laptop computers, and provide different output voltages through internal boost circuits and voltage stabilizing circuits, thereby achieving a portable function. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a control circuit diagram of the present invention;

[0015] Figure 2 It is the external interface diagram;

[0016] Figure 3 It is the circuit diagram of the boost circuit;

[0017] Figure 4 It is the circuit diagram of the voltage stabilizing circuit;

[0018] Figure 5 This is the circuit diagram of the controller. DETAILED DESCRIPTION

[0019] 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.

[0020] A light source control system for machine vision includes a controller and a control circuit, wherein the control circuit includes a MOS tube Q5, wherein the MOS tube Q5 is an N-type MOS tube, wherein the gate G of the MOS tube Q5 is connected to the controller via a first line 1, wherein the drain D of the MOS tube Q5 is connected to one terminal of a wiring terminal P6 via a third line 3, wherein the other terminal of the wiring terminal P6 is connected to the output terminal of a power supply, and the wiring terminal P6 is used to connect a light source. The source of the MOS tube Q5 is grounded via a fourth line 4. The controller can output a voltage via the first line 1 and thus can control the conduction or disconnection of the MOS tube Q5. When the controller outputs a high level to the first line 1, the MOS tube Q5 is turned on, the third line 3 and the fourth line 4 are connected, and the light source is turned on. When the controller outputs a low level to the first line 1, the MOS tube Q5 is disconnected, and the light source is turned off.

[0021] The control circuit also includes a second line 2, one end of which is connected to the output end of the power supply, and the other end is connected to the third line 3, and a resistor R21 is arranged on the second line 2. R21 acts as a dummy load. Without the resistor R21, the drain of the MOS tube Q5 is in a high impedance state, which is easily disturbed by the outside world, resulting in an unstable drain voltage, which in turn causes the MOSFET to switch incorrectly, and may even cause the circuit to oscillate at a high frequency or become unstable. Of course, in practice, the resistor R21 may not be required.

[0022] It only needs to provide a small load current, but not too large a current, so a larger resistance value is better.

[0023] The control circuit also includes a resistor R28 and a fifth circuit 5 arranged on the fourth circuit 4. The resistor R28 is a sampling resistor. One end of the fifth circuit 5 is connected to the portion of the fourth circuit 4 between the MOS tube Q5 and the resistor R28. The other end of the fifth circuit 5 is connected to the controller. The controller can obtain the voltage on the resistor R28, and then the current passing through the light source can be known according to the voltage and the resistance value of the resistor R28. When the current passing through the light source is too large or too small, the controller can control the MOS tube Q5 to turn off.

[0024] A resistor R27 is provided on the fifth line 5, and the control circuit further includes a sixth line 6, one end of the sixth line 6 is connected to a side of the fifth line 5 located downstream of the resistor R27, and the other end is grounded, and a capacitor C16 is provided on the sixth line 6, and the resistor R27 and the capacitor C16 form an RC filter circuit.

[0025] The control circuit further includes a seventh line 7, one end of which is connected to one end of the fifth line 5 connected to the controller, and the other end is grounded. A voltage stabilizing diode D8 is provided on the seventh line 7. When the voltage stabilizing diode D8 is not broken down, the voltage stabilizing diode D8 makes the seventh line 7 unidirectionally conductive along the direction from the ground end to the fifth line 5. When the voltage output to the controller on the fifth line 5 exceeds the breakdown voltage of the voltage stabilizing diode D8, the voltage stabilizing diode D8 is reversely conductive, thereby making the voltage output to the controller from the fifth line 5 not exceed a predetermined value, thereby protecting the controller.

[0026] The system also includes an external interface JP1, a boost circuit and a voltage stabilizing circuit. The external interface JP1 is used to connect to an external device, which can be a mobile phone, a laptop computer, etc., and the entire system is powered by the external device. The external interface JP1 has a first output terminal, which can output the same voltage as the power supply of the external device. The mobile phone and the laptop computer are generally 3.7V. The boost circuit has a first input terminal, which is used to connect to the first output terminal. The boost circuit also includes a voltage stabilizing chip U1, an eighth line 8, a second output terminal, an inductor L1, a diode D1, a capacitor C1, and a capacitor C2. One end of the eighth line 8 is connected to the first input terminal, and the other end is connected to the second output terminal. The inductor L1 and the diode D1 are sequentially arranged on the eighth line 8 along the direction from the first input terminal to the second output terminal. The diode D1 allows the current on the eighth line 8 to flow unidirectionally along the direction from the first input terminal to the second output terminal. One end of the capacitor C1 and the capacitor C2 are connected to the side of the eighth line 8 close to the output terminal. The voltage stabilizing chip U1 is TPS55340, and the pins SW1, SW15, and SW16 of the voltage stabilizing chip U1 are respectively connected to the part of the eighth line 8 located between the inductor L1 and the diode D1. A MOSFET switch is provided inside the voltage stabilizing chip U1. When the MOSFET switch is turned on, the voltage input from the first input terminal enters the inside of the voltage stabilizing chip U1, the inductor starts to store electric energy, and the capacitor C1 and the capacitor C2 discharge to the second output terminal. When the MOSFET switch is turned off, the inductor L1 starts to discharge, and the inductor L1 outputs a voltage to the second output terminal through the diode D1, and charges the capacitor C1 and the capacitor C2 at the same time. By means of the inductor L1, the capacitor C1, and the capacitor C2, a voltage boost can be achieved. In practice, the second output terminal outputs a voltage of 12V. The external interface JP1 has a first enable output terminal TP8, and the voltage stabilizing chip U1 has a first enable input terminal EN, and the first enable output terminal TP8 is connected to the first enable input terminal EN, so that the switch of the voltage stabilizing chip U1 can be controlled by an external device. The voltage stabilizing chip U1 adopts an existing chip, and the specific principle is not described here. The second output end is the output end of the power supply.

[0027] The voltage stabilizing circuit includes a linear voltage stabilizing chip U2, the input end of the linear voltage stabilizing chip U2 is connected to the first output end through a ninth line 9, the output end of the linear voltage stabilizing chip U2 is connected to a tenth line 10, and the power supply end of the controller is connected to the tenth line 10, that is, the controller is powered by the linear voltage stabilizing chip U2. The linear voltage stabilizing chip U2 has a second enable input end EN, and the second enable input end EN is connected to the first enable output end EN. When the voltage output by the external device through the first enable output end EN is lower than a predetermined value (0.2V), the boost circuit and the voltage stabilizing circuit stop outputting, and the microcontroller and the light source are powered off to avoid continuous power supply to the circuit when the voltage is low, thereby reducing energy consumption.

[0028] 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 control system for machine vision, characterized in that: include: Controller; The control circuit comprises a MOS tube Q5, wherein the MOS tube Q5 is an N-type MOS tube, a gate G of the MOS tube Q5 is connected to a controller via a first line, a drain D of the MOS tube Q5 is connected to one terminal of a wiring terminal P6 via a third line, the other terminal of the wiring terminal is connected to an output end of a power supply, and the light source is mounted on the wiring terminal; the source of the MOS tube Q5 is grounded via a fourth line; the controller can output a voltage via the first line and thus can control the conduction or disconnection of the MOS tube Q5, thereby controlling the switch of the light source.

2. A light source control system for machine vision according to claim 1, characterized in that: The control circuit further includes a second circuit, one end of the second circuit is connected to the output end of the power supply, and the other end is connected to the third circuit, and a resistor R21 is arranged on the second circuit.

3. A light source control system for machine vision according to claim 2, characterized in that: The control circuit also includes a resistor R28 and a fifth circuit arranged on a fourth circuit. One end of the fifth circuit is connected to a portion of the fourth circuit located between the MOS tube Q5 and the resistor R28. The other end of the fifth circuit is connected to a controller. The controller can obtain the voltage on the resistor R28, and then calculate the current of the light source through the voltage and the resistance value of the resistor R28. When the current passing through the light source is too large or too small, the controller can control the MOS tube Q5 to turn off.

4. A light source control system for machine vision according to claim 3, characterized in that: A resistor R27 is arranged on the fifth line, and the control circuit further includes a sixth line, one end of the sixth line is connected to a side of the fifth line located downstream of the resistor R27, and the other end is grounded, and a capacitor C16 is arranged on the sixth line, and the resistor R27 and the capacitor C16 form an RC filter circuit.

5. A light source control system for machine vision according to claim 4, characterized in that: The control circuit also includes a seventh circuit, one end of which is connected to one end of the fifth circuit connected to the controller, and the other end is grounded. A voltage-stabilizing diode D8 is provided on the seventh circuit. When the voltage-stabilizing diode D8 is not broken down, the voltage-stabilizing diode D8 enables the seventh circuit to be unidirectionally conducted in a direction from the ground end toward the fifth circuit.

6. A light source control system for machine vision according to claim 5, characterized in that: Also includes: An external interface, used for connecting an external device, having a first output terminal and a first enable output terminal; A boost circuit, comprising a first input terminal, a second output terminal and a first enable input terminal, wherein the first input terminal is connected to the first output terminal, and the output terminal of the power supply is the second output terminal; The voltage stabilizing circuit has an input terminal connected to the first output terminal, a second enable input terminal connected to the first enable output terminal, and an output terminal connected to the controller to supply power to the controller.

7. A light source control system for machine vision according to claim 6, characterized in that: The external device is a mobile phone or a laptop computer.

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