Laser driving circuit

Abstract

The utility model discloses a laser drive circuit which comprises an analog switch, an adjustable voltage source, a laser and an MCU. The starting output end of the analog switch is connected with the PWM signal output end of the MCU, the signal input end of the adjustable voltage source is connected with the PWM signal output end of the MCU and the enabling signal output end of the MCU, the output end of the adjustable voltage circuit is connected with the signal input end of the laser, and the anode of the laser is connected with the signal output port of the adjustable voltage source. According to the invention, by adjusting the adjustable voltage source, the PWM and the current limiting of the current-limiting resistor, the current flowing into the laser can drive the laser, and the magnitude of the current input into the laser and the frequency of the input current can be adjusted at the same time. While the performance of the laser driving circuit is improved, the complexity of the driving circuit is also reduced.

Description

Technical Field

[0001] The utility model relates to the field of laser technology, in particular to a laser driving circuit. Background Art

[0002] In related technologies, current control chips are generally used as the main driving components to adjust the current size and timing of the input laser, so as to control the laser to generate corresponding laser light power and timing.

[0003] Limited by the complexity of existing current control chips and their numerous pins, the risk of driver circuit failure increases, resulting in high costs and complex implementation. In actual use, when driving a laser to dim, it is often necessary to adjust the laser's luminous power and timing. This requires adjusting the input laser current and its frequency, or timing. How to use a relatively simple driver circuit to achieve this adjustment of laser luminous power and timing is a technical problem that currently needs to be solved. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the utility model provides a laser driving circuit that solves the problems in the prior art of easy failure of the driver, high cost of use and complex implementation.

[0005] In order to achieve the above-mentioned purpose of the utility model, the technical solution adopted by the utility model is: a laser driving circuit, including: an analog switch, an adjustable voltage source, a laser, and an MCU;

[0006] The enable output end of the analog switch is connected to the PWM signal output end of the MCU, the signal input end of the adjustable voltage source is respectively connected to the PWM signal output end of the MCU and the enable signal output end of the MCU, the output end of the adjustable voltage circuit is connected to the signal input end of the laser, the laser anode is connected to the adjustable voltage source signal output port, and the laser cathode is connected to the signal input end of the analog switch.

[0007] Furthermore: the analog switch includes a single-pole double-throw analog switch U2 of model TS5A3160, the NO terminal of the single-pole double-throw analog switch U2 is connected to the ground resistor R2, the NC terminal of the single-pole double-throw analog switch U2 is connected to the ground resistor R3, the COM terminal of the single-pole double-throw analog switch U2 serves as the signal input terminal of the analog switch, the IN terminal of the single-pole double-throw analog switch U2 serves as the enable input terminal of the analog switch, the IN terminal of the single-pole double-throw analog switch U2 is also connected to the ground resistor R1, and the V+ terminal of the single-pole double-throw analog switch U2 is connected to the ground capacitor C1.

[0008] Furthermore, the adjustable voltage source includes a DC-DC power supply chip U6 of model SY8891E, and the VIN terminal of the DC-DC power supply chip U6 serves as the power input terminal of the adjustable voltage source. The VIN terminal of the DC-DC power supply chip U6 is also connected to one end of the resistor R10, one end of the resistor R11, and one end of the capacitor C9, respectively. The other end of the resistor R10 is connected to the PG terminal of the DC-DC power supply chip U6, and the other end of the resistor R11 is connected to the EN terminal of the DC-DC power supply chip U6 and one end of the resistor R14, respectively. The other end of the resistor R14 is connected to the other end of the capacitor C9, the DC-DC The GND end of the power chip U6, one end of the resistor R15 and one end of the capacitor C10 are connected, the other end of the resistor R15 is respectively connected to the FB end of the DC-DC power chip U6, one end of the resistor R12, one end of the resistor R13 and one end of the capacitor C8, the other end of the resistor R13 serves as the signal input end of the adjustable voltage source, the other end of the resistor R12 is respectively connected to the other end of the capacitor C8, the other end of the capacitor C10 and one end of the inductor L1, the other end of the inductor L1 is connected to the LX end of the DC-DC power chip U6, and the other end of the capacitor C10 also serves as the output end of the DC-DC power chip U6.

[0009] Furthermore: the MCU is any microcontroller that supports PWM function.

[0010] The beneficial effects of the utility model are:

[0011] 1. By adjusting the size of the adjustable voltage source and the input analog switch PWM timing, combined with the current limiting of the current limiting resistor, the adjustable voltage source, the PWM and the current limiting resistor can regulate the input current size and timing, thereby controlling the laser output power and timing according to the current;

[0012] 2. By adjusting the adjustable voltage source, the PWM, and the current limiting resistor, the current flowing into the laser can drive the laser, and the magnitude of the current input to the laser and the frequency of the input current, i.e., the timing, can be adjusted simultaneously. This improves the performance of the laser driving circuit while reducing the complexity of the driving circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A module block diagram of a laser driving circuit provided in an embodiment of the present disclosure.

[0014] Figure 2 A schematic diagram of an analog switch and current-limiting resistor provided in an embodiment of the present disclosure.

[0015] Figure 3A schematic diagram of an adjustable voltage source provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0016] The specific implementation methods of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific implementation methods. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations conceived using the present invention are protected.

[0017] like Figure 1 As shown, in one embodiment of the present utility model, a laser driving circuit is provided, comprising: an analog switch, an adjustable voltage source, a laser, and an MCU;

[0018] The enable output end of the analog switch is connected to the PWM signal output end of the MCU, the signal input end of the adjustable voltage source is respectively connected to the PWM signal output end of the MCU and the enable signal output end of the MCU, the output end of the adjustable voltage circuit is connected to the signal input end of the laser, the laser anode is connected to the adjustable voltage source signal output port, and the laser cathode is connected to the signal input end of the analog switch.

[0019] like Figure 2 As shown, further, the analog switch includes a single-pole double-throw analog switch U2 of model TS5A3160, the NO terminal of the single-pole double-throw analog switch U2 is connected to the ground resistor R2, the NC terminal of the single-pole double-throw analog switch U2 is connected to the ground resistor R3, the COM terminal of the single-pole double-throw analog switch U2 serves as the signal input terminal of the analog switch, the IN terminal of the single-pole double-throw analog switch U2 serves as the enable input terminal of the analog switch, the IN terminal of the single-pole double-throw analog switch U2 is also connected to the ground resistor R1, and the V+ terminal of the single-pole double-throw analog switch U2 is connected to the ground capacitor C1.

[0020] like Figure 3As shown, further, the adjustable voltage source includes a DC-DC power supply chip U6 of model SY8891E, and the VIN end of the DC-DC power supply chip U6 serves as the power input end of the adjustable voltage source. The VIN end of the DC-DC power supply chip U6 is also respectively connected to one end of the resistor R10, one end of the resistor R11 and one end of the capacitor C9, the other end of the resistor R10 is connected to the PG end of the DC-DC power supply chip U6, the other end of the resistor R11 is respectively connected to the EN end of the DC-DC power supply chip U6 and one end of the resistor R14, the other end of the resistor R14 is respectively connected to the other end of the capacitor C9, the DC-D The GND end of the C power chip U6, one end of the resistor R15 and one end of the capacitor C10 are connected, the other end of the resistor R15 is respectively connected to the FB end of the DC-DC power chip U6, one end of the resistor R12, one end of the resistor R13 and one end of the capacitor C8, the other end of the resistor R13 serves as the signal input end of the adjustable voltage source, the other end of the resistor R12 is respectively connected to the other end of the capacitor C8, the other end of the capacitor C10 and one end of the inductor L1, the other end of the inductor L1 is connected to the LX end of the DC-DC power chip U6, and the other end of the capacitor C10 also serves as the output end of the DC-DC power chip U6.

[0021] Furthermore, the laser driving circuit further includes a current limiting resistor circuit, and the current limiting resistor circuit is connected between the enable output port of the analog switch and the voltage reference ground.

[0022] Furthermore, the MCU is any microcontroller that supports PWM function. Preferably, in this embodiment, a microcontroller of model stm32f103c8t6 is used. In addition, any microcontroller that supports PWM function, such as PIC16F877A, Arduino Uno R3, etc., can be used.

[0023] The working principle of the utility model is as follows: the adjustable voltage circuit is configured to provide a voltage signal Vout to the laser anode;

[0024] The analog switch is configured to switch between the current limiting resistors R2 and R3 under the control of PWM_P1, thereby generating different drive currents and timings in the laser; the MCU is configured to adjust the voltage of the adjustable voltage source and the switching frequency of the analog switch, so as to adjust the anode supply voltage of the laser and the regulation of the current limiting resistor.

[0025] When the laser drive circuit is powered on, the value of the output voltage VCC_OUT of the step-down circuit is approximately 3.0V. By adjusting the voltage at the TEC_DAC terminal by the MCU, the voltage at the VCC_OUT terminal can be appropriately reduced. The output size of the VCC_OUT voltage will affect the amplitude of the laser output voltage. In this embodiment, the adjustable voltage source is configured to have an output voltage of approximately 3.0V. On the analog switch side, the analog switch U2 can be controlled to switch on and off by the MCU's signal output of PWM_P1, that is, under the control of the PWM_P1 signal, the analog switch can be switched to connect to the resistor R2 or R3. Specifically, when the PWM_P1 output is a high level, the analog switch is connected to the resistor R2, and when the PWM_P1 output is a low level, the analog switch is connected to the resistor R3. By controlling the connection between the analog switch and R2 or R3 by PWM_P1, the current flowing through the laser can be adjusted, and the laser light emitting power and timing can be adjusted.

[0026] While embodiments of the present invention have been described above, these embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, numerous modifications and variations are possible based on the above description. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better utilize the present invention and its modifications. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A laser driving circuit, characterized in that: include: Analog switches, adjustable voltage sources, lasers, MCUs; The enable output end of the analog switch is connected to the PWM signal output end of the MCU, the signal input end of the adjustable voltage source is respectively connected to the PWM signal output end of the MCU and the enable signal output end of the MCU, the output end of the adjustable voltage source is connected to the signal input end of the laser, the laser anode is connected to the adjustable voltage source signal output port, and the laser cathode is connected to the signal input end of the analog switch.

2. The laser driving circuit according to claim 1, wherein: The analog switch includes a single-pole double-throw analog switch U2 of model TS5A3160, the NO terminal of the single-pole double-throw analog switch U2 is connected to the ground resistor R2, the NC terminal of the single-pole double-throw analog switch U2 is connected to the ground resistor R3, the COM terminal of the single-pole double-throw analog switch U2 serves as the signal input terminal of the analog switch, the IN terminal of the single-pole double-throw analog switch U2 serves as the enable input terminal of the analog switch, the IN terminal of the single-pole double-throw analog switch U2 is also connected to the ground resistor R1, and the V+ terminal of the single-pole double-throw analog switch U2 is connected to the ground capacitor C1.

3. The laser driving circuit according to claim 1, wherein: The adjustable voltage source includes a DC-DC power supply chip U6 of model SY8891E, and the VIN terminal of the DC-DC power supply chip U6 serves as the power input terminal of the adjustable voltage source. The VIN terminal of the DC-DC power supply chip U6 is also connected to one end of the resistor R10, one end of the resistor R11 and one end of the capacitor C9 respectively. The other end of the resistor R10 is connected to the PG terminal of the DC-DC power supply chip U6, and the other end of the resistor R11 is connected to the EN terminal of the DC-DC power supply chip U6 and one end of the resistor R14 respectively. The other end of the resistor R14 is connected to the other end of the capacitor C9, the DC-DC power supply chip The GND end of the DC-DC power supply chip U6, one end of the resistor R15 and one end of the capacitor C10 are connected. The other end of the resistor R15 is respectively connected to the FB end of the DC-DC power supply chip U6, one end of the resistor R12, one end of the resistor R13 and one end of the capacitor C8. The other end of the resistor R13 serves as the signal input end of the adjustable voltage source. The other end of the resistor R12 is respectively connected to the other end of the capacitor C8, the other end of the capacitor C10 and one end of the inductor L1. The other end of the inductor L1 is connected to the LX end of the DC-DC power supply chip U6. The other end of the capacitor C10 also serves as the output end of the DC-DC power supply chip U6.

4. The laser driving circuit according to claim 1, wherein: The MCU is any microcontroller that supports PWM function.

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