Adaptive constant current regulation driving system

Abstract

The utility model relates to laser drive field, concretely for adaptive constant current regulation and control drive system, include: control circuit, voltage reducing circuit and current detection circuit, the first input of voltage reducing circuit is connected DC power supply, the second input of voltage reducing circuit and the output of control circuit are connected, for accessing analog control signal, control first output end is used for driving laser, the second output of voltage reducing circuit is connected with the input of current detection circuit, and the output of current detection circuit is connected with the input of control circuit. The utility model controls the amplitude of output drive current of voltage reducing circuit through analog control signal, and the correct output drive current is ensured through the detection of the current amplitude of output, therefore when using different specifications of laser, need not replacing or modifying the hardware of drive module to drive module, only need to change drive current amplitude through singlechip control, satisfy the requirement of various specifications of laser to current amplitude.

Description

Technical Field

[0001] This utility model relates to the field of laser driving, specifically an adaptive constant current control driving system. Background Technology

[0002] Lasers are widely used due to their high brightness and strong directionality, and each laser requires a matching driver module for operation. Different application scenarios require different specifications of lasers, and each specification requires its own driver module to provide the appropriate drive current. This results in a wide variety of laser driver modules, and using different specifications of lasers necessitates replacing the driver module or modifying its hardware. Summary of the Invention

[0003] To address the problem of the wide variety of drive module specifications caused by the need for separate drive modules to drive lasers of different specifications, this invention provides an adaptive constant current control drive system.

[0004] This utility model is achieved using the following technical solution: an adaptive constant current control drive system, comprising: a control circuit, a step-down circuit, and a current detection circuit. The first input terminal of the step-down circuit is connected to a DC power supply, and the second input terminal of the step-down circuit is connected to the output terminal of the control circuit for receiving an analog control signal. The first output terminal is used to drive a laser. The second output terminal of the step-down circuit is connected to the input terminal of the current detection circuit, and the output terminal of the current detection circuit is connected to the input terminal of the control circuit.

[0005] The output of the control circuit is used to output an analog control signal to control the current amplitude output by the buck circuit. The input of the control circuit is used to receive the current magnitude detected by the current detection circuit. The control circuit adjusts the analog control signal based on the feedback current detection signal until the current output by the buck circuit reaches the set current amplitude. The driving current amplitude output by the buck circuit of this drive system can be adjusted to drive lasers of different specifications.

[0006] The aforementioned adaptive constant current control drive system uses a DC / DC control chip U12 (model LT3796) in its step-down circuit. The control circuit includes a microcontroller, a DA chip U3, and an AD sampling chip U10. The microcontroller U1 is an STM32F103 series, the DA chip U3 is model AD5625BCPZ, and the AD sampling chip U10 is model 74HC4067DB. Pin 24 of U12 is connected to the DC power supply VIN+ through the twelfth resistor R12 and grounded through the seventeenth resistor R17. Pin 23 is also connected to the DC power supply VIN+ and the source of PMOS transistor M1 through the thirteenth resistor R13. Pins 1 and 2 are connected to the two ends of the thirteenth resistor R13. The gate of PMOS transistor M1 is connected to pin 3, and the drain of PMOS transistor M1 is connected to the positive output terminal. The negative output terminal is connected to the... The three inductors L3 are connected to the drain of NMOS transistor M2, the gate of NMOS transistor M2 is connected to pin 19, and the source of NMOS transistor M2 is grounded through the twenty-eighth resistor R28. Pin 9 of U12 is connected to pin 1 of chip U3 through the twenty-first resistor R21 and the eighteenth resistor R18, and pin 9 is also grounded through the twenty-second resistor R22. Pin 14 of U12 is connected to pin 39 of microcontroller U1, and pin 5 is connected to pin 8 of chip U10. Pins 92 and 93 of microcontroller U1 are connected to pins 7 and 8 of DA chip U3, respectively. Pins 24, 81, 84, 85, 86, and 87 of microcontroller U1 are connected to pins 1, 15, 10, 11, 14, and 13 of AD sampling chip U10, respectively.

[0007] The positive and negative output terminals of the buck circuit are connected to the laser. The chip U12 in the buck circuit has a current detection function. Pins 1 and 2 of U12 are used to acquire the current signal in the buck circuit. The current signal is transmitted to the AD acquisition chip U10 in the control circuit through pin 5 of U12. The AD acquisition chip U10 transmits the real-time current signal fed back by the buck circuit to the microcontroller U1. The microcontroller U1 controls the DA chip U3 to output a DA signal, which controls pin 9 of the buck circuit chip U12 to achieve linear adjustment of the output drive current of the buck circuit.

[0008] This invention controls the amplitude of the output drive current of the step-down circuit using analog control signals. By detecting the amplitude of the output current, the correctness of the output drive current is ensured. Therefore, when using lasers of different specifications, there is no need to replace or modify the hardware of the drive module; the amplitude of the drive current can be changed simply by controlling it with a microcontroller to meet the current amplitude requirements of various laser specifications. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the principle of this utility model.

[0010] Figure 2This is the circuit diagram of a step-down circuit.

[0011] Figure 3 This is the circuit diagram of the microcontroller in the control circuit.

[0012] Figure 4 This is a circuit diagram of the DA chip in the control circuit.

[0013] Figure 5 This is a circuit diagram of the AD sampling chip in the control circuit. Detailed Implementation

[0014] An adaptive constant current control drive system includes: a control circuit, a step-down circuit, and a current detection circuit, such as... Figure 1 As shown, the output of the control circuit is used to output an analog control signal to control the current amplitude output by the buck circuit; the input of the control circuit is used to receive the current magnitude detected by the current detection circuit. The control circuit adjusts the analog control signal based on the feedback current detection signal until the current output by the buck circuit reaches the set current amplitude.

[0015] The first input terminal of the buck circuit is used to step down the DC power supply; the second input terminal of the buck circuit is used to input an analog control signal to control the current amplitude of the first output terminal; the first output terminal of the buck circuit is used to drive the laser; and the second output terminal of the buck circuit is used for current detection by the current detection circuit.

[0016] The analog control signal controls the output current amplitude of the buck circuit. The current detection circuit detects the output current amplitude of the buck circuit and feeds the information back to the control circuit. The DC power supply provides a preset voltage to the buck circuit.

[0017] like Figure 2As shown, the step-down circuit uses a DC / DC control chip U12 of model LT3796. Pin 24 of U12 is connected to the DC power supply VIN+ through the twelfth resistor R12 and grounded through the seventeenth resistor R17. Pin 23 is also connected to the DC power supply VIN+ and, through the thirteenth resistor R13, to the source of PMOS transistor M1. Pins 1 and 2 are connected to the two ends of the thirteenth resistor R13, respectively. The gate of PMOS transistor M1 is connected to pin 3, and the drain of PMOS transistor M1 is connected to the positive output terminal. The negative output terminal is connected to the drain of NMOS transistor M2 through the third inductor L3. The gate of NMOS transistor M2 is connected to pin 19. The source of the OS transistor M2 is grounded through the 28th resistor R28, and the drain of the NMOS transistor M2 is also connected to the power supply VIN+ through the freewheeling diode D4; pin 9 of U12 is connected to pin 1 of chip U3 through the 21st resistor R21 and the 18th resistor R18, and pin 9 is also grounded through the 22nd resistor R22. The two ends of the branch connected by the 21st resistor R21 and the 22nd resistor R22 are also connected in parallel with the 36th capacitor C36; pin 14 of U12 is connected to pin 39 (PE8) of microcontroller U1, and pin 5 is connected to pin 8 of chip U10.

[0018] The positive and negative output terminals of the buck converter are connected to the laser. The buck converter judges the PWM signal at pin 14 of U12. If the PWM signal is received at pin 14, pin 19 of U12 outputs a high level, and NMOS transistor M2 is turned on. If the PWM signal is not received at pin 14, pin 19 of U12 outputs a low level, and NMOS transistor M2 is turned off. The buck converter is started and stopped through pin 14. After receiving the DA signal at pin 9 of U12, a square wave signal is output at pin 3. The duty cycle of the square wave signal is adjusted according to the DA signal. The square wave signal output at pin 3 controls the switching frequency of PMOS transistor M1, realizing linear adjustment of the output current of the buck converter, so that the drive system can drive lasers of different specifications. In the buck converter, pins 1 and 2 of U12 collect the voltage difference across the thirteenth resistor R13, and transmit the current signal to the AD acquisition chip U10 in the control circuit through pin 5 of U12.

[0019] like Figure 3 , Figure 4 and Figure 5As shown, the control circuit includes a microcontroller, a DA chip U3, and an AD sampling chip U10. The microcontroller U1 used in the control circuit is an STM32F103 series. Pin 39 (PE8) of the microcontroller U1 outputs a PWM signal to pin 14 of the buck converter chip U12 to control the on / off state of the output current. Pins 92 and 93 of the microcontroller U1 are connected to pins 7 and 8 of the DA chip U3 (model AD5625BCPZ) respectively. By controlling the DA chip U3 to output a DA signal, the DA chip U3 controls pin 9 of the buck converter chip U12 to achieve linear current regulation. Pins 24, 81, 84, 85, 86, and 87 of the microcontroller U1 are connected to pins 1, 15, 10, 11, 14, and 13 of the AD sampling chip U10 (model 74HC4067DB), respectively. Pin 8 of the AD sampling chip U10 is connected to pin 5 of the step-down circuit chip U12. Pin 5 of U12 transmits the current signal to the AD acquisition chip U10 in the control circuit. The AD acquisition chip U10 transmits the real-time current signal fed back from the step-down circuit to the microcontroller U1.

[0020] The analog control signals are the PWM signal (PWMOUT1) and DA signal (DAOUT1) provided by the control circuit to the buck circuit.

[0021] In the current detection circuit, pins 1 and 2 of U12 in the step-down circuit acquire the current signal in the step-down circuit, and transmit the current signal to the AD acquisition chip U10 in the control circuit through pin 5 of U12.

[0022] The DC power supply provides a preset voltage VIN to the step-down circuit.

Claims

1. An adaptive constant current control drive system, characterized in that: include: The circuit includes a control circuit, a step-down circuit, and a current detection circuit. The first input terminal of the step-down circuit is connected to a DC power supply. The second input terminal of the step-down circuit is connected to the output terminal of the control circuit to receive an analog control signal. The first output terminal of the control circuit is used to drive the laser. The second output terminal of the step-down circuit is connected to the input terminal of the current detection circuit, and the output terminal of the current detection circuit is connected to the input terminal of the control circuit.

2. The adaptive constant current control drive system according to claim 1, characterized in that: The step-down circuit uses the LT3796 DC / DC control chip U12. The control circuit includes a microcontroller, a DA chip U3, and an AD sampling chip U10. The microcontroller U1 is an STM32F103 series, the DA chip U3 is an AD5625BCPZ, and the AD sampling chip U10 is a 74HC4067DB. Pin 24 of U12 is connected to the DC power supply VIN+ through the twelfth resistor R12 and grounded through the seventeenth resistor R17. Pin 23 is also connected to the DC power supply VIN+ and the source of the PMOS transistor M1 through the thirteenth resistor R13. Pins 1 and 2 are connected to the thirteenth resistor R17. The gate of PMOS transistor M1 is connected to pin 3 across resistor R13, the drain of PMOS transistor M1 is connected to the positive output terminal, and the negative output terminal is connected to the drain of NMOS transistor M2 through the third inductor L3. The gate of NMOS transistor M2 is connected to pin 19, and the source of NMOS transistor M2 is grounded through the twenty-eighth resistor R28. Pin 9 of U12 is connected to pin 1 of chip U3 through the twenty-first resistor R21 and the eighteenth resistor R18, and pin 9 is also grounded through the twenty-second resistor R22. Pin 14 of U12 is connected to pin 39 of microcontroller U1, and pin 5 is connected to pin 8 of chip U10. Pins 92 and 93 of microcontroller U1 are connected to pins 7 and 8 of DA chip U3, respectively. Pins 24, 81, 84, 85, 86, and 87 of microcontroller U1 are connected to pins 1, 15, 10, 11, 14, and 13 of AD sampling chip U10, respectively.

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