Control adjustable constant current source circuit for infrared light source of injection molding machine mold monitor

Abstract

The invention relates to the technical field of adjustable constant current source control circuits, in particular to an adjustable constant current source control circuit for an infrared light source of an injection molding machine mold monitor, which comprises a PC (Personal Computer) upper computer communication circuit, a light source control circuit and an LED (Light Emitting Diode) constant current source comparison circuit, the PC upper computer communication circuit comprises a serial port communication unit, a photoelectric isolation unit, a communication chip unit, an LED indication unit and a power supply and filtering unit. On the basis of a constant current source driver realized by an existing pure hardware circuit, an output current adjustable function is realized, and on the basis of an existing light source constant current source driver with adjustable current, high precision and high response effects which are comparable with those of a pure hardware circuit constant current source are realized. On the basis that a constant current source circuit is realized by traditional software, ADC sampling, conversion, operation and the like are omitted, and the efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of controllable constant current source circuits, in particular to a controllable constant current source circuit for an infrared light source of an injection molding machine mold monitor. Background Art

[0002] In the injection molding machine mold monitor industry, the infrared light source that supplements the mold monitor light must be a constant source circuit to drive the LED lamp beads. However, the common infrared light sources and LED constant current source drive circuits on the market have the following shortcomings: 1. Use pure hardware circuit to achieve constant current: Advantages: fast response and high constant current accuracy.

[0003] Disadvantages: Fixed current (light source brightness cannot be adjusted).

[0004] 2. Use a combination of software and hardware to achieve constant current: Advantages: Output current is adjustable.

[0005] Disadvantages: Long response time after software adjustments, excessive MCU computing power consumption, and poor constant current accuracy. (This method achieves constant current output by typically using an ADC to read the voltage of a sampling resistor, calculating the current, and then adjusting the output current by controlling the output duty cycle using PWM.) Summary of the Invention

[0006] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions: A control and adjustable constant current source circuit for an infrared light source of an injection molding machine mold monitor, comprising a PC host computer communication circuit, a light source control circuit, and an LED constant current source comparison circuit; The PC host computer communication circuit includes a serial communication unit, a photoelectric isolation unit, a communication chip unit, an LED indication unit, and a power supply and filter unit.

[0007] The serial communication unit includes J8 and J9, both of which are four-pin interfaces, wherein the four pins of J8 are RX-, RX+, TX- and TX+, and the four pins of J9 are UART3 RX-, UART3 RX+, UART3 TX- and UART3 TX+; The optoelectronic isolation unit includes eight optocouplers, namely D20, D21, D22, D23, D24, D25, D26 and D27; The communication chip unit includes U25 and U26. U25 is set with eight pins 1-8, which are VCC, RXD, TXD, GND, Y, Z, B and A. U26 is set with eight pins 1-8, which are VCC, RXD, TXD, GND, Y, Z, B and A. The LED indicator unit includes two D_0805_LED_GREEN green LED indicators; The filter unit includes four filter capacitors, namely C58, C59, C60 and C61.

[0008] The RX-, RX+, TX-, and TX+ serial ports are respectively connected to the differential input pin Y, differential input pin Z, differential output pin B, and differential input pin A of U25 through connectors, and the access ends of the connectors are respectively connected to resistors R-0805-33R 95R, R-0805-33R 96R, R-0805-33R 97R, and R-0805-33R 98R; Optocouplers D24 and D25 are connected in series, with both ends of the series circuit connected in parallel with the line from TX- to pin B and the line from TX+ to pin A, respectively. D22 is connected to the series circuit of D24 and D25. Optocouplers D26 and D27 are connected in series, with both ends of the series circuit connected in parallel with the line from RX+ to pin Z and the line from RX- to pin Y, respectively. D23 is connected to the series circuit of D26 and D27. The line from TX- to pin B and the line from RX+ to pin Z are connected in parallel to GND ground, and R91 and R92 are connected to the ground line. The line from RX- to pin Y and the line from TX+ to pin A are connected in parallel to the power supply, and R93 and R94 are connected to the parallel lines. The GND pin of the communication chip unit U25 is grounded, the TXD pin of U25 is connected to TXD, the RXD pin of U25 is connected to RXD, the VCC pin of U25 is connected to the power supply, and two GNDs are connected in parallel to the power supply line. The two ground lines are connected to C59 and C58 respectively. A group of green LED indicators are connected in parallel to the RXD line from the RXD pin of U25, and the parallel lines are connected to the power supply. R87 and R90 are connected to the power supply to the LED indicator and the RXD line respectively. A group of green LED indicators are connected in parallel to the TXD pin of U25, and the parallel lines are connected to the power supply. R88 and R89 are connected to the power supply to the LED indicator and the TXD line respectively. UART3 RX-, UART3 RX+, UART3 TX- and UART3 TX+ serial ports are connected to the Y, Z, B and A pins of U26 respectively through the connector. The line from UART3 TX- to pin B and the line from UART3 RX+ to pin Z are connected to ground in parallel. R101 and R102 are connected to the ground line. The line from UART3 RX- to pin Y and UART3 The line from TX+ to pin A is connected to ground in parallel, and R103 and R104 are connected to the ground line. The GND pin of U26 is grounded, the TXD pin of U26 is connected to UART2-TXD, and the RXD pin of U26 is connected to UART2-RXD. A power supply is connected in parallel on the line from the TXD pin to UART2-TXD and the line from the RXD pin to UART2-RXD. R99 and R100 are connected to the power supply to UART2-TXD and UART2-RXD lines respectively. The VCC pin of U26 is connected to the power supply, and two GND grounds are connected in parallel on the line from the VCC pin to the power supply. C61 and C60 are connected to the two GND ground lines respectively.

[0009] Wherein, the light source control circuit includes an LED driving circuit, an LED sampling circuit and an LED control circuit; The LED driver circuit includes U12. U12 has eight pins 1-8, namely NC, IN, SD, NC, VCC, OUTD, OUTS and GND. Pin IN is connected to LIGHT1-PWM, and the line from pin IN to LIGHT1-PWM is connected to R30. Pin SD is connected to LIGHT1-SD, and the line from pin SD to LIGHT1-SD is connected to R33. The line from pin SD to LIGHT1-SD is connected in parallel with a power supply, and the parallel line is connected to R26. Pin VCC is connected to a power supply, and the line from pin VCC to the power supply is connected in parallel with GND, and the ground line is connected to C32. The LED driving circuit also includes U13, which has three pins D, G, and S. The OUTD pin and OUTS pin of U12 are connected to the G pin of U13. The line from the OUTD pin to the G pin and the line from the OUTS pin to the G pin are connected to R32 and R34 respectively. The GND pin of U12 is grounded, the S pin of U13 is grounded to GNDIN, and the D pin of U13 is connected to D10. The LED sampling circuit includes an amplifier U10. U10 has five pins 1-5, namely OUT, GND, IN+, IN- and VS. The OUT pin of U10 is grounded to GND, and the line from the OUT pin to the grounded GND is connected to LIGHT1-ADC. The line from the OUT pin to the LIGHT1-ADC is connected to R22, and the line from LIGHT1-ADC to GND is connected to C31. The GND pin of U10 is grounded to GND, the IN+ pin of U10 is connected to the cathode No. 2 of the diode D10, and the IN- pin of U10 is connected to J6. J6 has four pins 1-4, namely LED-, LED+, NC and NC. The IN- pin of U10 is connected to the LED+ pin of J6, and the anode No. 1 of the diode D10 is connected to the L The ED- pins are connected, L4 is connected to the line from the positive pole of D10 No. 1 to the LED- pin, C37 is connected in parallel to the line from the positive pole of D10 No. 1 to L4 and the line from the negative pole of D10 No. 2 to NI+, R25 and C33 are connected in parallel to the line from the negative pole of D10 No. 2 to IN+ and the line from J6 to IN-, R23 and R28 are connected to the line from the negative pole of D10 No. 2 to IN+ and the line from J6 to IN- between R25 and C33 respectively, one of the NC pins of J6 is connected to LIGHT1-24VSEL, the VS pin of U10 is grounded to GND, C38 is connected to the line from the VS pin to the ground GND, C39 is connected in parallel to the line from the VS pin to C38, the negative pole No. 2 of C39 is connected to the power supply, and the positive pole No. 1 of C39 is grounded to GND; The LED control circuit includes a chip U15. U15 is provided with five pins 1-5, namely A, B, GND, Y and VCC. The A pin of U15 is connected to LIGHT1-INT, and LIGHT1-INT is connected in parallel with a power supply and Q6. Q6 is provided with three pins 1-3, and the A pin of U15 is connected to pin 3 of Q6. R40 is connected to the line from the VCC-3.3V power supply to the A pin of U15. The B pin of U15 is connected to LIGHT1-CONTROL, and LIGHT1-CONTROL is connected in parallel with a power supply and a rectifier bridge stack. The GND pin of U15 is grounded GND. The Y pin of U15 is connected to LIGHT-SD. The VCC pin of U15 is connected to the power supply. Pin 1 of Q6 is connected to LIGHT1-SHORT-OUT, and a ground GND is connected in parallel between pin 2 and pin 1 of Q6. R48 is connected to the line between LIGHT1-SHORT-OUT and GND. There are four pins 1-4 on the rectifier bridge stack, of which pin 1 is the positive output pin, pin 2 is the AC input and output pin, pin 3 is the AC input and output pin, and pin 4 is the negative output pin. LIGHT1-CONTROL is connected to pin 4, pin 1 of the rectifier bridge stack is connected to LIGHT1-TRIGGERB, and R43 is connected to the line from LIGHT1-TRIGGERB to pin 1. Pin 2 of the rectifier bridge stack is connected to LIGHT1-TRIGGERA, and R44 is connected to the line from LIGHT1-TRIGGERA to pin 2. C45 and R38 are connected in parallel on the line from R43 to pin 1 and the line from R44 to pin 2.

[0010] Among them, the LED constant current source comparison circuit includes comparators U11A and U11B, U11A is provided with five pins, namely, No. 2 Y pin, No. 3 + pin, No. 4 - pin, No. 5 + pin and No. 12, U11B is provided with No. 1 Y pin, No. 3 + pin, No. 6 - pin, No. 7 + pin and No. 12, a total of five pins, No. 2 Y pin of U11A is connected to LIGHT1-ADD, R29 is connected to the line from No. 2 Y pin to LIGHT1-ADD, and ground GND is connected in parallel to the line from R29 to LIGHT1-ADD, C40 is connected to the line between GND and LIGHT1-ADD, and No. 3 + pin of U11A is connected to Power supply, R27 is connected in parallel between the line from pin 3+ to the power supply and the line from R29 to LIGHT1-ADD. Pin 4- of U11A is connected to LIGHT1-ADC. R24 is connected to the line connecting pin 4- to LIGHT1-ADC. Two ground GNDs are connected in parallel between R24 and pin 4-. C34 and C35 are connected to the two GNDs respectively. Pin 5+ of U11A is connected to LIGHT1-DAC. R31 is connected to the line connecting pin 5+ to LIGHT1-DAC. Two ground GNDs are connected in parallel between R31 and pin 5+. C41 and C42 are connected to the two GNDs respectively. The No. 1 Y pin of U11B is connected to LIGHT1-SUB, and R45 is connected to the line between the No. 1 Y pin and LIGHT1-SUB. The No. 3 + pin of U11B is connected to the power supply. R41 is connected in parallel between the line between the No. 3 + pin and the power supply and between R45 and LIGHT1-SUB. The line between R45 and LIGHT1-SUB is also connected in parallel with GND. GND and the line between LIGHT1-SUB are connected with C46. The No. 6 - pin of U11B is connected in parallel with R31 and the line between LIGHT1-DAC and grounded to GND. The No. 6 - pin is connected in parallel with R31 and grounded to GND. R35 is connected to the parallel line of LIGHT1-DAC, R37 is connected to GND and the parallel line, R36 is connected to the line between the parallel line and pin 6-, two ground GNDs are connected in parallel on the line between R36 and pin 6-, and C43 and C44 are connected to the two GNDs respectively. Pin 7+ of U11B is connected to LIGHT1-ADC, R46 is connected to the line connecting pin 7+ and LIGHT1-ADC, two ground GNDs are connected in parallel on the line between R46 and pin 7+, and C47 and C48 are connected to the two GNDs respectively.

[0011] The beneficial effects of the present invention are as follows: 1. The present invention realizes the output current adjustable function based on the existing constant current source driver realized by pure hardware circuit.

[0012] 2. Based on the existing current-adjustable constant current source driver for light sources, the present invention achieves high precision and high response comparable to that of a pure hardware circuit constant current source.

[0013] 3. Based on the traditional software implementation of the constant current source circuit, the present invention omits ADC sampling, conversion, calculation, etc., which is conducive to improving efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a system modular block diagram of the present invention; Figure 2 is a communication circuit diagram of the present invention; Figure 3 This is the LED driving and sampling circuit diagram of the present invention; Figure 4 This is a comparison circuit diagram of an LED constant current source according to the present invention; Figure 5 It is a circuit diagram of the single chip microcomputer of the present invention. DETAILED DESCRIPTION

[0015] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0016] This application provides an adjustable constant current source circuit for controlling infrared light sources of injection molding machine mold monitors, which mainly solves * problems and provides the following technical solutions. Figure 1-Figure 5 Give detailed instructions: A control and adjustable constant current source circuit for an infrared light source of an injection molding machine mold monitor, comprising a PC host computer communication circuit, a light source control circuit, and an LED constant current source comparison circuit; The PC host computer communication circuit includes a serial communication unit, a photoelectric isolation unit, a communication chip unit, an LED indication unit, and a power supply and filter unit; The serial communication unit includes J8, which has a four-pin interface with RX-, RX+, TX- and TX+, and J9, which has a four-pin interface with UART3 RX-, UART3 RX+, UART3 TX- and UART3 TX+. The optoelectronic isolation unit includes eight optocouplers, namely D20, D21, D22, D23, D24, D25, D26 and D27; The communication chip units include U25 and U26. Both U25 and U26 use MAX3490 chips. U25 has eight pins 1-8, which are VCC, RXD, TXD, GND, Y, Z, B, and A. U26 has eight pins 1-8, which are VCC, RXD, TXD, GND, Y, Z, B, and A. The LED indicator unit includes two D_0805_LED_GREEN green LED indicators; The power supply and filter unit includes a 3.3V power supply and four filter capacitors, namely C58, C59, C60, and C61; The RX-, RX+, TX-, and TX+ serial ports are connected to the differential input pin Y, differential input pin Z, differential output pin B, and differential input pin A of U25 respectively through the J-XH49-2.54MM connector. The access end of the J-XH49-2.54MM connector is connected to the resistors R-0805-33R 95R, R-0805-33R 96R, R-0805-33R 97R, and R-0805-33R 98R respectively. Optocouplers D24 and D25 are connected in series, with both ends of the series circuit connected in parallel with the line from TX- to pin B and the line from TX+ to pin A, respectively. D22 is also connected to the series circuit of D24 and D25. Optocouplers D26 and D27 are connected in series, with both ends of the series circuit connected in parallel with the line from RX+ to pin Z and the line from RX- to pin Y, respectively. D23 is also connected to the series circuit of D26 and D27. The line from TX- to pin B and the line from RX+ to pin Z are connected in parallel to GND ground. The ground line is connected to R91 and R92, and the model of R91 and R92 is R-0402-4.7K. The line from RX- to pin Y and the line from TX+ to pin A are connected in parallel to the VCC-3.3V power supply. The parallel lines are connected to R93 and R94, and the model of R93 and R94 is R-0402-4.7K. The GND pin of the communication chip unit U25 is grounded, the TXD pin of U25 is connected to TXD, the RXD pin of U25 is connected to RXD, the VCC pin of U25 is connected to the VCC-3.3V power supply, and two GNDs are connected in parallel on the VCC pin to VCC-3.3V line. The two ground lines are connected to C59 and C58 respectively. The C59 model is C-0805-10UF, and the C58 model is C-0402-100NF. A group of D_0805_LED_GREEN green LED indicators are connected in parallel on the RXD pin of U25 to the RXD line. The parallel line is connected to the VCC-3.3 V power supply connection, R87 and R90 are connected to the VCC-3.3V power supply to the LED indicator and the RXD line respectively. R87 model is R-0402-1K, and R90 model is R-0402-4.7K. A group of D_0805_LED_GREEN green LED indicators are connected in parallel to the TXD line from the TXD pin of U25. The parallel line is connected to the VCC-3.3V power supply. R88 and R89 are connected to the VCC-3.3V power supply to the LED indicator and the TXD line respectively. R88 model is R-0402-1K, and R89 model is R-0402-4.7K. UART3 RX-, UART3 RX+, UART3 TX- and UART3 TX+ serial ports via J-XH4P-2.5MM -NC connectors are connected to the Y, Z, B, and A pins of U26 respectively. The line from UART3 TX- to pin B and the line from UART3 RX+ to pin Z are grounded in parallel. R101 and R102 are connected to the ground line. The model of R101 is R-0402-4.7K-NC, and the model of R102 is R-0402-4.7K-NC. The line from UART3 RX- to pin Y and the line from UART3 The line from TX+ to pin A is connected to ground in parallel, and R103 and R104 are connected to the ground line. The model of R103 is R-0402-4.7K-NC, and the model of R104 is R-0402-4.7K-NC. The GND pin of U26 is grounded, the TXD pin of U26 is connected to UART2-TXD, and the RXD pin of U26 is connected to UART2-RXD. The line from TXD pin to UART2-TXD and the line from RXD pin to UART2-RXD are connected to VCC-3.3V power supply in parallel. The VCC-3.3V power supply is connected to UA The RT2-TXD and UART2-RXD lines are connected to R99 and R100 respectively. The R99 model is R-0402-4.7K-NC, and the R100 model is R-0402-4.7K-NC. The VCC pin of U26 is connected to the VCC-3.3V power supply. Two GND ground wires are connected in parallel on the line from the VCC pin to the VCC-3.3V power supply. The two GND ground lines are connected to C61 and C60 respectively. The C61 model is C-0805-10UF-NC, and the C60 model is C-0402-100NF-NC. The light source control circuit includes an LED driving circuit, an LED sampling circuit and an LED control circuit; The LED driver circuit includes a MOS tube U12, model EG3001, and U12 has eight pins 1-8, namely NC, IN, SD, NC, VCC, OUTD, OUTS and GND. Pin IN is connected to LIGHT1-PWM, and the line from pin IN to LIGHT1-PWM is connected to R30, model R-0402-1K. Pin SD is connected to LIGHT1-SD, and the line from pin SD to LIGHT1-SD is connected to R33, model R-0402-1K. The line from pin SD to LIGHT1-SD is connected in parallel with VCC-3.3V power supply, and the parallel line is connected with R26, model R-0402-10K. Pin VCC is connected to VCC-15V power supply, and the line from pin VCC to VCC-15V power supply is connected in parallel with GND grounding, and the ground line is connected with C32, model C32 is C-0402-100NF. The LED driving circuit also includes U13, which has three pins D, G, and S. The OUTD pin and OUTS pin of U12 are connected to the G pin of U13. The line from the OUTD pin to the G pin and the line from the OUTS pin to the G pin are connected to R32 and R34, respectively. The model of R32 is R-0805-33R, and the model of R34 is R-0805-10R. The GND pin of U12 is grounded, the S pin of U13 is grounded GNDIN, and the D pin of U13 is connected to a diode D10, and the model of D10 is D-1N5824-SS54-TP. The LED sampling circuit includes an amplifier U10, and the model of U10 is U-INA180A2. U10 has five pins 1-5, namely OUT, GND, IN+, IN- and VS. The OUT pin of U10 is grounded to GND, and the line from the OUT pin to the ground GND is connected to LIGHT1-ADC. The line from the OUT pin to the LIGHT1-ADC is connected to R22, and the model of R22 is R-0402-1K. The line from LIGHT1-ADC to GND is connected to C31, and the model of C31 is C-0402-1 00NF, U10's GND pin is grounded to GND, U10's IN+ pin is connected to the No. 2 cathode of diode D10, U10's IN- pin is connected to the photoelectric switch J6, J6 model is J-LED-DIP4, J6 is provided with 1-4 four pins, namely LED-, LED+, NC and NC, U10's IN- pin is connected to the LED+ pin of photoelectric switch J6, the No. 1 anode of diode D10 is connected to the LED- pin of J6, the No. 1 anode of D10 to the LED- pin is connected with the inductor L4, L4 model is L-CKST0630-10UH, C37 is connected in parallel on the line from D10's No. 1 positive pole to L4 and on the line from D10's No. 2 negative pole to NI+. The model of C37 is C-0402-100NF. R25 and C33 are connected in parallel on the line from D10's No. 2 negative pole to IN+ and on the line from J6 to IN-. The model of R25 is R2512-0.05R and the model of C33 is C-0402-100NF. R25 is connected to the line from D10's No. 2 negative pole to IN+ and on the line from J6 to IN- between R25 and C33. 23 and R28. R23 is R-0402-10R, R28 is R-0402-10R. One of the NC pins of J6 is connected to LIGHT1-24VSEL. The VS pin of U10 is grounded to GND. The line from the VS pin to GND is connected to C38. C38 is C-0402-100NF. The line from the VS pin to C38 is connected in parallel with C39. C39 is C-0402-10NF. The negative pole 2 of C39 is connected to the VCC-3.3V power supply. The positive pole 1 of C39 is grounded to GND. The LED control circuit includes a logic chip U15, the model of U15 is U-SN74LC1G32DBVR-SOT23-5, and there are five pins 1-5 on U15, namely A, B, GND, Y and VCC. The A pin of U15 is connected to LIGHT1-INT, and LIGHT1-INT is connected in parallel with VCC-3.3V power supply and Q6, the model of Q6 is Q-HSS2300A-SOT23, and there are three pins 1-3 on Q6. The A pin of U15 is connected to LIGHT1-INT, and the VCC-3.3V power supply and Q6 are connected in parallel. The pin is connected to pin 3 of Q6. R40 is connected to the line from VCC-3.3V power supply to pin A of U15. R40 model is R-0402-10K. Pin B of U15 is connected to LIGHT1-CONTROL. VCC-3.3V power supply and rectifier bridge stack are connected in parallel to LIGHT1-CONTROL. GND pin of U15 is grounded to GND. Y pin of U15 is connected to LIGHT-SD. VCC pin of U15 is connected to VCC-3.3V power supply. Pin 1 of Q6 is connected to LIGHT1-SHORT-OUT. A ground GND is connected in parallel between pin 2 and pin 1 of Q6. R48 is connected to the line between LIGHT1-SHORT-OUT and GND. The model of R48 is R-0402-4.7K. The rectifier bridge stack is provided with four pins 1-4, of which pin 1 is the positive output pin, pin 2 is the AC input and output pin, pin 3 is the AC input and output pin, and pin 4 is the negative output pin. LIGHT1-CONTROL is connected to pin 4, pin 1 of the rectifier bridge stack is connected to LIGHT1-TRIGGERB, and R43 is connected to the line from LIGHT1-TRIGGERB to pin 1. The R43 model is R-0402-4.7K. Pin 2 of the rectifier bridge stack is connected to LIGHT1-TRIGGERA, and R44 is connected to the line from LIGHT1-TRIGGERA to pin 2. The R44 model is R-0402-4.7K. C45 and R38 are connected in parallel on the line from R43 to pin 1 and the line from R44 to pin 2. The model of C45 is C-0402-10NF and the model of R38 is R-0402-4.7K. The LED constant current source comparison circuit includes comparators U11A and U11B. The models of U11A and U11B are both LM239DT. U11A is provided with five pins, namely, No. 2 Y pin, No. 3 + pin, No. 4 - pin, No. 5 + pin and No. 12. U11B is provided with five pins, namely, No. 1 Y pin, No. 3 + pin, No. 6 - pin, No. 7 + pin and No. 12. No. 2 Y pin of U11A is connected to LIGHT1-ADD, and No. 2 Y pin is connected to LIGHT1-ADD. The LIGHT1-ADD line is connected to R29, R29 model is R-0402-1K, the line from R29 to LIGHT1-ADD is connected in parallel with ground GND, GND and LIGHT1-ADD lines are connected to C40, C40 model is C-0402-100NF, U11A No. 3 + pin is connected to VCC-3.3V power supply, No. 3 + pin to VCC-3.3V power supply line and R29 to LIGHT1-A R27 is connected in parallel to the DD line. The model of R27 is R-0402-10K. The 4th pin of U11A is connected to LIGHT1-ADC. The line connected to the 4th pin and LIGHT1-ADC is connected to R24. The model of R24 is R-0402-1K. Two ground GNDs are connected in parallel to the line from R24 to the 4th pin. The two GNDs are connected to C34 and C35 respectively. The model of C34 is C-0402-10NF. The model is C-0402-100NF. The No. 5+ pin of U11A is connected to the LIGHT1-DAC. The line connecting the No. 5+ pin and the LIGHT1-DAC is connected to R31. The model of R31 is R-0402-1K. Two grounds GND are connected in parallel on the line from R31 to the No. 5+ pin. The two GNDs are connected to C41 and C42 respectively. The model of C41 is C-0402-10NF, and the model of C42 is C-0402-100NF. The No. 1 Y pin of U11B is connected to LIGHT1-SUB. The line between the No. 1 Y pin and LIGHT1-SUB is connected with R45, model R-0402-1K. The No. 3 + pin of U11B is connected to the VCC-3.3V power supply. The line between the No. 3 + pin and the VCC-3.3V power supply and the line between R45 and LIGHT1-SUB are connected in parallel with R41, model R-0402-10K. 45 and the LIGHT1-SUB line are also connected in parallel with GND grounding, GND and LIGHT1-SUB line are connected with C46, C46 model is C-0402-100NF, U11B No. 6 pin is connected in parallel with R31 and LIGHT1-DAC line and grounded GND, No. 6 pin is connected to the parallel line with R31 and LIGHT1-DAC with R35, R35 model is R-0402-100 R, GND and the parallel line are connected to R37, R37 model is R-0402-10K, the parallel line and the line between pin 6 are connected to R36, R36 model is R-0402-1K, the line between R36 and pin 6 is connected to two ground GNDs in parallel, the two GNDs are connected to C43 and C44 respectively, C43 model is C-0402-10NF, C44 model is C-0402-100 NF, U11B's 7#+ pin is connected to LIGHT1-ADC. The line connecting 7#+ pin and LIGHT1-ADC is connected to R46, model R-0402-1K. Two ground GNDs are connected in parallel on the line between R46 and 7#+ pin. The two GNDs are connected to C47 and C48 respectively. Model C47 is C-0402-10NF, and model C48 is C-0402-100NF. Controller constant current principle: After the device is powered on, the MCU resets. After reset, it outputs an analog value based on the default light source brightness. Simultaneously, the MCU program's main loop periodically detects the output of the light source's constant current circuit, comparing the results and determining whether output current adjustment is necessary based on the input IO. If adjustment is necessary, it reaches the target current value within 1ms.

[0017] Dimming function implementation principle: The PC sends commands to the MCU via the RS422 serial port. The MCU interprets the user-set light source brightness value and records it. The DAC then quantizes the value and outputs the corresponding analog value. Immediately after the DAC outputs the analog value, it requests adjustment of the light source brightness, achieving the target brightness within 1ms.

[0018] Using two comparator channels from the LM239 four-channel comparator, the analog value from the DAC output by the MCU is used as a reference. The analog value is divided into two paths: one path is directly connected to the comparator (current high limit), and the other path is divided by a resistor and then enters the comparator (current low limit). Depending on the voltage output by the current acquisition circuit, there are several situations: 1. If the voltage output by the current acquisition circuit is within the allowable range of the analog output of the MCU, the two comparators will not output and the MCU will not adjust the output current PWM duty cycle.

[0019] 2. If the voltage output by the current acquisition circuit is higher than the analog value output by the MCU, the constant current comparator will subtract the comparator output signal, and the MCU will reduce the high-level time of the current PWM duty cycle according to the IO signal. The current will then drop to within the set value range.

[0020] 3. If the voltage output by the current acquisition circuit is lower than the analog value output by the MCU, the constant current comparator will add the comparator output signal, and the MCU will increase the high level time of the current PWM duty cycle according to the IO signal. The current will then rise to within the set value range.

[0021] This realizes the constant current principle.

[0022] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control circuit for an infrared light source of an injection molding machine mold monitor, characterized in that: Including PC host computer communication circuit, light source control circuit and LED constant current source comparison circuit; The PC host computer communication circuit includes a serial communication unit, a photoelectric isolation unit, a communication chip unit, an LED indication unit, and a power supply and filter unit.

2. The adjustable constant current source circuit for controlling the infrared light source of an injection molding machine mold monitor according to claim 1, characterized in that: The serial communication unit includes J8 and J9, both of which are four-pin interfaces, wherein the four pins of J8 are RX-, RX+, TX- and TX+ respectively, and the four pins of J9 are UART3 RX-, UART3 RX+, UART3 TX- and UART3 TX+ respectively; The optoelectronic isolation unit includes eight optocouplers, namely D20, D21, D22, D23, D24, D25, D26 and D27; The communication chip unit includes U25 and U26. U25 is set with eight pins 1-8, which are VCC, RXD, TXD, GND, Y, Z, B and A. U26 is set with eight pins 1-8, which are VCC, RXD, TXD, GND, Y, Z, B and A. The LED indicator unit includes two D_0805_LED_GREEN green LED indicators; The filter unit includes four filter capacitors, namely C58, C59, C60 and C61.

3. The adjustable constant current source circuit for controlling the infrared light source of an injection molding machine mold monitor according to claim 2, characterized in that: The RX-, RX+, TX- and TX+ serial ports are respectively connected to the differential input pin Y, differential input pin Z, differential output pin B and differential input pin A of U25 through connectors, and the access ends of the connectors are respectively connected to the resistors R-0805-33R 95R, R-0805-33R 96R, R-0805-33R 97R and R-0805-33R 98R; Optocouplers D24 and D25 are connected in series, with both ends of the series circuit connected in parallel with the line from TX- to pin B and the line from TX+ to pin A, respectively. D22 is connected to the series circuit of D24 and D25. Optocouplers D26 and D27 are connected in series, with both ends of the series circuit connected in parallel with the line from RX+ to pin Z and the line from RX- to pin Y, respectively. D23 is connected to the series circuit of D26 and D27. The line from TX- to pin B and the line from RX+ to pin Z are connected in parallel to GND ground, and R91 and R92 are connected to the ground line. The line from RX- to pin Y and the line from TX+ to pin A are connected in parallel to the power supply, and R93 and R94 are connected to the parallel lines. The GND pin of the communication chip unit U25 is grounded, the TXD pin of U25 is connected to TXD, the RXD pin of U25 is connected to RXD, the VCC pin of U25 is connected to the power supply, and two GNDs are connected in parallel to the power supply line. The two ground lines are connected to C59 and C58 respectively. A group of green LED indicators are connected in parallel to the RXD line from the RXD pin of U25, and the parallel lines are connected to the power supply. R87 and R90 are connected to the power supply to the LED indicator and the RXD line respectively. A group of green LED indicators are connected in parallel to the TXD pin of U25, and the parallel lines are connected to the power supply. R88 and R89 are connected to the power supply to the LED indicator and the TXD line respectively. UART3 RX-, UART3 RX+, UART3 TX- and UART3 TX+ serial ports are connected to the Y, Z, B and A pins of U26 respectively through the connector. The line from UART3 TX- to pin B and the line from UART3 RX+ to pin Z are connected to ground in parallel. R101 and R102 are connected to the ground line. The line from UART3 RX- to pin Y and UART3 The line from TX+ to pin A is connected to ground in parallel, and R103 and R104 are connected to the ground line. The GND pin of U26 is grounded, the TXD pin of U26 is connected to UART2-TXD, and the RXD pin of U26 is connected to UART2-RXD. A power supply is connected in parallel on the line from the TXD pin to UART2-TXD and the line from the RXD pin to UART2-RXD. R99 and R100 are connected to the power supply to UART2-TXD and UART2-RXD lines respectively. The VCC pin of U26 is connected to the power supply, and two GND grounds are connected in parallel on the line from the VCC pin to the power supply. C61 and C60 are connected to the two GND ground lines respectively.

4. The adjustable constant current source circuit for controlling the infrared light source of an injection molding machine mold monitor according to claim 1, characterized in that: The light source control circuit includes an LED driving circuit, an LED sampling circuit and an LED control circuit; The LED driver circuit includes U12. U12 has eight pins 1-8, namely NC, IN, SD, NC, VCC, OUTD, OUTS and GND. Pin IN is connected to LIGHT1-PWM, and the line from pin IN to LIGHT1-PWM is connected to R30. Pin SD is connected to LIGHT1-SD, and the line from pin SD to LIGHT1-SD is connected to R33. The line from pin SD to LIGHT1-SD is connected in parallel with a power supply, and the parallel line is connected to R26. Pin VCC is connected to a power supply, and the line from pin VCC to the power supply is connected in parallel with GND, and the ground line is connected to C32. The LED driving circuit also includes U13, which has three pins D, G, and S. The OUTD pin and OUTS pin of U12 are connected to the G pin of U13. The line from the OUTD pin to the G pin and the line from the OUTS pin to the G pin are connected to R32 and R34 respectively. The GND pin of U12 is grounded, the S pin of U13 is grounded to GNDIN, and the D pin of U13 is connected to D10. The LED sampling circuit includes an amplifier U10. U10 has five pins 1-5, namely OUT, GND, IN+, IN- and VS. The OUT pin of U10 is grounded to GND, and the line from the OUT pin to the grounded GND is connected to LIGHT1-ADC. The line from the OUT pin to the LIGHT1-ADC is connected to R22, and the line from LIGHT1-ADC to GND is connected to C31. The GND pin of U10 is grounded to GND, the IN+ pin of U10 is connected to the cathode No. 2 of the diode D10, and the IN- pin of U10 is connected to J6. J6 has four pins 1-4, namely LED-, LED+, NC and NC. The IN- pin of U10 is connected to the LED+ pin of J6, and the anode No. 1 of the diode D10 is connected to the L The ED- pins are connected, L4 is connected to the line from the positive pole of D10 No. 1 to the LED- pin, C37 is connected in parallel to the line from the positive pole of D10 No. 1 to L4 and the line from the negative pole of D10 No. 2 to NI+, R25 and C33 are connected in parallel to the line from the negative pole of D10 No. 2 to IN+ and the line from J6 to IN-, R23 and R28 are connected to the line from the negative pole of D10 No. 2 to IN+ and the line from J6 to IN- between R25 and C33 respectively, one of the NC pins of J6 is connected to LIGHT1-24VSEL, the VS pin of U10 is grounded to GND, C38 is connected to the line from the VS pin to the ground GND, C39 is connected in parallel to the line from the VS pin to C38, the negative pole No. 2 of C39 is connected to the power supply, and the positive pole No. 1 of C39 is grounded to GND; The LED control circuit includes a chip U15. U15 is provided with five pins 1-5, namely A, B, GND, Y and VCC. The A pin of U15 is connected to LIGHT1-INT, and LIGHT1-INT is connected in parallel with a power supply and Q6. Q6 is provided with three pins 1-3, and the A pin of U15 is connected to pin 3 of Q6. R40 is connected to the line from the VCC-3.3V power supply to the A pin of U15. The B pin of U15 is connected to LIGHT1-CONTROL, and LIGHT1-CONTROL is connected in parallel with a power supply and a rectifier bridge stack. The GND pin of U15 is grounded GND. The Y pin of U15 is connected to LIGHT-SD. The VCC pin of U15 is connected to the power supply. Pin 1 of Q6 is connected to LIGHT1-SHORT-OUT, and a ground GND is connected in parallel between pin 2 and pin 1 of Q6. R48 is connected to the line between LIGHT1-SHORT-OUT and GND. There are four pins 1-4 on the rectifier bridge stack, of which pin 1 is the positive output pin, pin 2 is the AC input and output pin, pin 3 is the AC input and output pin, and pin 4 is the negative output pin. LIGHT1-CONTROL is connected to pin 4, pin 1 of the rectifier bridge stack is connected to LIGHT1-TRIGGERB, and R43 is connected to the line from LIGHT1-TRIGGERB to pin 1. Pin 2 of the rectifier bridge stack is connected to LIGHT1-TRIGGERA, and R44 is connected to the line from LIGHT1-TRIGGERA to pin 2. C45 and R38 are connected in parallel on the line from R43 to pin 1 and the line from R44 to pin 2.

5. The adjustable constant current source circuit for controlling the infrared light source of an injection molding machine mold monitor according to claim 1, characterized in that: The LED constant current source comparison circuit includes comparators U11A and U11B. U11A is provided with five pins, namely, No. 2 Y pin, No. 3 + pin, No. 4 - pin, No. 5 + pin and No. 12 pin. U11B is provided with five pins, namely, No. 1 Y pin, No. 3 + pin, No. 6 - pin, No. 7 + pin and No. 12 pin. No. 2 Y pin of U11A is connected to LIGHT1-ADD. R29 is connected to the line from No. 2 Y pin to LIGHT1-ADD. Ground GND is connected in parallel to the line from R29 to LIGHT1-ADD. C40 is connected to the line between GND and LIGHT1-ADD. No. 3 + pin of U11A is connected to the power supply. , R27 is connected in parallel to the line from the No. 3 + pin to the power supply and the line from R29 to LIGHT1-ADD, U11A's No. 4 - pin is connected to LIGHT1-ADC, R24 is connected to the line connecting the No. 4 - pin to LIGHT1-ADC, two ground GNDs are connected in parallel from R24 to the No. 4 - pin, and C34 and C35 are connected to the two GNDs respectively, U11A's No. 5 + pin is connected to LIGHT1-DAC, R31 is connected to the line connecting the No. 5 + pin to LIGHT1-DAC, R31 is connected to the line connecting the No. 5 + pin to LIGHT1-DAC, two ground GNDs are connected in parallel from R31 to the No. 5 + pin, and C41 and C42 are connected to the two GNDs respectively; The No. 1 Y pin of U11B is connected to LIGHT1-SUB, and R45 is connected to the line between the No. 1 Y pin and LIGHT1-SUB. The No. 3 + pin of U11B is connected to the power supply. R41 is connected in parallel between the line between the No. 3 + pin and the power supply and between R45 and LIGHT1-SUB. The line between R45 and LIGHT1-SUB is also connected in parallel with GND. GND and the line between LIGHT1-SUB are connected with C46. The No. 6 - pin of U11B is connected in parallel with R31 and the line between LIGHT1-DAC and grounded to GND. The No. 6 - pin is connected in parallel with R31 and grounded to GND. R35 is connected to the parallel line of LIGHT1-DAC, R37 is connected to GND and the parallel line, R36 is connected to the line between the parallel line and pin 6-, two ground GNDs are connected in parallel on the line between R36 and pin 6-, and C43 and C44 are connected to the two GNDs respectively. Pin 7+ of U11B is connected to LIGHT1-ADC, R46 is connected to the line connecting pin 7+ and LIGHT1-ADC, two ground GNDs are connected in parallel on the line between R46 and pin 7+, and C47 and C48 are connected to the two GNDs respectively.

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