Multi-channel PWM light source modulation device

Abstract

The utility model aims to provide the multi-channel PWM light source modulation device which is low in cost, small in size, strong in operability and convenient to debug. The device comprises a host computer, a control module, a PWM modulation module, a lamp source plate and a product to be detected, the product to be detected comprises an ambient light detection sensor, the lamp source plate comprises a plurality of groups of light emitting diodes, the host computer, the control module, the PWM modulation module and the lamp source plate are connected in sequence, and the ambient light detection sensor is connected with the host computer. The to-be-detected product is arranged on one side of the light emitting diode, the ambient light detection sensor detects the light source frequency of the light emitting diode, and the to-be-detected product is in light frequency communication with the control module. The utility model is applied to the technical field of optical sensor function detection.

Description

Technical Field

[0001] The utility model is applied to the technical field of optical sensor function detection, and particularly relates to a multi-channel PWM light source modulation device. Background Art

[0002] ALS refers to ambient light sensor; PWM refers to pulse width modulation; MCU refers to microprocessor; LED refers to light emitting diode; the detection cost of the prior art is relatively high, the debugging process is relatively cumbersome, it occupies a large space, and multiple Agilent / 33250A are required, with a large cost. Designing a circuit using multiple AD9850 signal generation chips also has a large cost. At present, some electronic products need to undergo function detection through an ambient light sensor. However, in some occasions, the environment cannot meet the conditions for using data line communication and wireless communication, and optical frequency communication is required. Therefore, it is necessary to provide a multi-channel PWM light source modulation device with low cost, small volume, strong operability, and convenient debugging. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a multi-channel PWM light source modulation device with low cost, small volume, strong operability, and convenient debugging.

[0004] The technical solution adopted by the utility model is as follows: the utility model includes a host computer, a control module, a PWM modulation module, a light source board, and a product to be tested. The product to be tested includes an ambient light detection sensor. The light source board includes several groups of light emitting diodes. The host computer, the control module, the PWM modulation module, and the light source board are connected in sequence. The product to be tested is arranged on one side of the light emitting diodes. The ambient light detection sensor detects the light source frequency of the light emitting diodes. The product to be tested performs optical frequency communication with the control module.

[0005] As can be seen from the above solution, the model of the control module is STM32F103, which is configured with 15-way PWM drive circuits. Compared with the prior art, it has a relatively high cost, is not convenient for debugging, and occupies a large space. This application has the advantages of low cost, multi-channel, convenient integration, very small volume, strong operability, convenient debugging, and fast circuit response speed.

[0006] A preferred solution is that the PWM modulation module includes a first resistor, a second resistor, a first diode, a second diode, a first voltage source, a second voltage source, and an MOS transistor. The first resistor is connected in parallel with the first diode. One end of the first resistor and the cathode of the first diode are branched into two paths. One path is connected to the control module, and the other path is connected to the first voltage source. The other end of the first resistor and the anode of the first diode are branched into two paths. One path is grounded through the second resistor, and the other path is connected to the gate of the MOS transistor. The source of the MOS transistor is grounded, and the drain of the MOS transistor is connected to the cathode of the second diode. The anode of the second diode is branched into two paths. One path is connected to the second voltage source through the second resistor, and the other path is connected to the light source board.

[0007] A preferred solution is that the multi-channel PWM light source modulation device further includes a first connection board and a second connection board. The anode of the second diode is connected to the first connection board. The first connection board is connected to the second connection board, and the second connection board is connected to the light source board.

[0008] A preferred solution is that when the PWM modulation module inputs a high level, the first resistor is used to prevent the instantaneous current from being too large, thus playing a current limiting role. The second resistor charges Cgs, thereby accelerating the opening of the MOS transistor. The second resistor also plays a role in stabilizing the VGS voltage of the MOS transistor. When the VGS of the MOS transistor > 2.5V, the DS of the MOS transistor is fully turned on, the second diode is forward biased, the second diode generates current, and the light source of the second diode emits light.

[0009] A preferred solution is that when the PWM modulation module inputs a low level, the first diode, the first resistor, and the second resistor provide a discharge circuit, which plays a role in accelerating the turn-off of the DS of the MOS transistor. The current of the second diode is cut off, the light source of the second diode goes out, and the first resistor provides an electrostatic discharge circuit to prevent the MOS transistor from being electrostatically broken down. Description of the Drawings

[0010] Figure 1 is the structural block diagram of the present invention;

[0011] Figure 2 is the system block diagram of the present invention;

[0012] Figure 3 is the circuit schematic diagram of the PWM modulation module;

[0013] Figure 4 is the first simulation waveform diagram of the PWM modulation module;

[0014] Figure 5is the second simulation waveform of the PWM modulation module;

[0015] Figure 6 is the third simulation waveform of the PWM modulation module. Detailed implementation manners

[0016] As Figures 1 to 6 shown, in this embodiment, the present utility model includes a host computer 1, a control module 2, a PWM modulation module 3, a light source board 4, and a product under test 5. The product under test 5 includes an ambient light detection sensor 6. The light source board 4 includes a plurality of groups of light-emitting diodes 7. The host computer 1, the control module 2, the PWM modulation module 3, and the light source board 4 are connected in sequence. The product under test 5 is disposed on one side of the light-emitting diodes 7. The ambient light detection sensor 6 detects the light source frequency of the light-emitting diodes 7. The product under test 5 performs optical frequency communication with the control module 2.

[0017] The host computer 1 executes a program and sends a pressure control instruction to the control module 2. The control module 2 executes a measurement program and outputs a PWM signal. The PWM modulation module 3 transmits the signal to the drive circuit of the light-emitting diodes 7, and then outputs an enhanced PWM signal. The enhanced PWM signal drives the on-off frequency of the light-emitting diodes 7. The ambient light detection sensor 6 detects the light source frequency of the light-emitting diodes 7. The product under test 5 calibrates and analyzes the detected frequency into a digital signal, and performs optical frequency communication with the control module 2.

[0018] As Figures 1 to 6 shown, in this embodiment, the PWM modulation module 3 includes a first resistor R3, a second resistor R2, a first diode D1, a second diode D3, a first voltage source V1, a second voltage source V2, and a MOS transistor M1. The first resistor R3 is connected in parallel with the first diode D1. One end of the first resistor R3 and the cathode of the first diode D1 are branched into two paths. One path is connected to the control module 2, and the other path is connected to the first voltage source V1. The other end of the first resistor R3 and the anode of the first diode D1 are branched into two paths. One path is grounded through the second resistor R2, and the other path is connected to the gate of the MOS transistor M1. The source of the MOS transistor M1 is grounded. The drain of the MOS transistor M1 is connected to the cathode of the second diode D3. The anode of the second diode D3 is branched into two paths. One path is connected to the second voltage source V2 through the second resistor R2, and the other path is connected to the light source board 4.

[0019] As Figures 1 to 6As shown, in this embodiment, the multi-channel PWM light source modulation device further includes a first connecting plate 8 and a second connecting plate 9. The positive electrode of the second diode D3 is connected to the first connecting plate 8. The first connecting plate 8 is connected to the second connecting plate 9, and the second connecting plate 9 is connected to the light source board 4.

[0020] As Figures 1 to 6 As shown, in this embodiment, when the PWM modulation module 3 inputs a high level, the first resistor R3 is used to prevent excessive instantaneous current, thereby playing a current limiting role and preventing the parasitic capacitance and inductance from forming an LC oscillation. The second resistor R2 charges Cgs, thereby accelerating the opening of the MOS transistor M1. The second resistor R2 also plays a role in stabilizing the VGS voltage of the MOS transistor M1. When the VGS of the MOS transistor M1 > 2.5V, the DS of the MOS transistor M1 is fully turned on, the second diode D3 is forward biased, the second diode D3 generates current, and the light source of the second diode D3 emits light. Here, Cgs refers to the capacitance between the gate and source of the MOS transistor M1, DS refers to the impedance from the drain to the source of the MOS transistor M1, and VGS refers to the gate-source voltage of the MOS transistor (M1).

[0021] As Figures 1 to 6 As shown, in this embodiment, when the PWM modulation module 3 inputs a low level, the first diode D1, the first resistor R3, and the second resistor R2 provide a discharge circuit, which plays a role in accelerating the turn-off of the DS of the MOS transistor M1. The current of the second diode D3 is cut off, and the light source of the second diode D3 goes out. The first resistor R3 provides an electrostatic discharge circuit to prevent the MOS transistor M1 from being electrostatically broken down. By cycling the above process to adjust the PWM wave, the LED emission frequency can be adjusted.

Claims

1. A multi-channel PWM light source modulation device, characterized in that: It includes a host computer (1), a control module (2), a PWM modulation module (3), a light source board (4), and a product under test (5). The product under test (5) includes an ambient light detection sensor (6). The light source board (4) includes several groups of light-emitting diodes (7). The host computer (1), the control module (2), the PWM modulation module (3), and the light source board (4) are connected in sequence. The product under test (5) is arranged on one side of the light-emitting diodes (7). The ambient light detection sensor (6) detects the light source frequency of the light-emitting diodes (7). The product under test (5) communicates with the control module (2) through optical frequency.

2. The multi-channel PWM light source modulation device according to claim 1, characterized in that: The PWM modulation module (3) includes a first resistor (R3), a second resistor (R2), a first diode (D1), a second diode (D3), a first voltage source (V1), a second voltage source (V2), and a MOS transistor (M1). The first resistor (R3) is connected in parallel with the first diode (D1). One end of the first resistor (R3) and the negative electrode of the first diode (D1) are divided into two paths. One path is connected to the control module (2), and the other path is connected to the first voltage source (V1). The other end of the first resistor (R3) and the positive electrode of the first diode (D1) are divided into two paths. One path is grounded through the second resistor (R2), and the other path is connected to the gate of the MOS transistor (M1). The source of the MOS transistor (M1) is grounded. The drain of the MOS transistor (M1) is connected to the negative electrode of the second diode (D3). The positive electrode of the second diode (D3) is divided into two paths. One path is connected to the second voltage source (V2) through the second resistor (R2), and the other path is connected to the light source board (4).

3. The multi-channel PWM light source modulation device according to claim 2, characterized in that: The multi-channel PWM light source modulation device further includes a first connecting plate (8) and a second connecting plate (9). The positive electrode of the second diode (D3) is connected to the first connecting plate (8). The first connecting plate (8) is connected to the second connecting plate (9). The second connecting plate (9) is connected to the light source board (4).

4. A multi-channel PWM light source modulation device according to claim 2, characterized in that: When a high level is input to the PWM modulation module (3), the first resistor (R3) is used to prevent the instantaneous current from being too large, thereby playing a current limiting role. The second resistor (R2) charges Cgs, thereby accelerating the opening of the MOS transistor (M1). The second resistor (R2) also plays a role in stabilizing the VGS voltage of the MOS transistor (M1). When the VGS of the MOS transistor (M1) > 2.5V, the DS of the MOS transistor (M1) is fully turned on, the second diode (D3) is forward biased, the second diode (D3) generates current, and the light source of the second diode (D3) emits light. Here, Cgs refers to the capacitance between the gate and the source of the MOS transistor (M1); DS refers to the impedance from the drain to the source of the MOS transistor (M1), and VGS refers to the gate-source voltage of the MOS transistor (M1).

5. A multi-channel PWM light source modulation device according to claim 2, characterized in that: When the PWM modulation module (3) inputs a low level, the first diode (D1), the first resistor (R3), and the second resistor (R2) provide a discharge circuit, which plays a role in accelerating the turn-off of the DS of the MOS transistor (M1). The current of the second diode (D3) is cut off, and the light source of the second diode (D3) goes out. The first resistor (R3) provides an electrostatic discharge circuit to prevent the MOS transistor (M1) from being broken down by static electricity.

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