Search

CN-224205073-U - PD detection alarm protection circuit of laser instrument

CN224205073UCN 224205073 UCN224205073 UCN 224205073UCN-224205073-U

Abstract

The utility model relates to a PD detection alarm protection circuit of a laser, which comprises a PD sensor, a resistor voltage division circuit, an in-phase proportional amplifying circuit, a comparator circuit and a voltage reference circuit, wherein the PD sensor collects PD photocurrent signals of the laser and sends the PD photocurrent signals to the resistor voltage division circuit, the resistor voltage division circuit converts the PD photocurrent signals into PD voltage signals and sends the PD voltage signals to the in-phase proportional amplifying circuit, the in-phase proportional amplifying circuit amplifies the PD voltage signals and sends the PD voltage signals to one input end of the comparator circuit, the other input end of the comparator circuit is connected with the voltage reference circuit, the output end of the comparator circuit outputs processed PD signals, and the detection reliability is remarkably improved while the cost is reduced and the detection response speed is very fast by optimizing a front-stage amplifying architecture and a rear-stage reference design. And can be monitored in real time by an upper computer. The system is particularly suitable for a safety protection system of industrial laser equipment.

Inventors

  • YE TAO
  • ZHAO YU

Assignees

  • 武汉思创精密激光科技有限公司

Dates

Publication Date
20260505
Application Date
20250519

Claims (10)

  1. 1. The PD detection alarm protection circuit of the laser is characterized by comprising a PD sensor, a resistor divider circuit, an in-phase proportional amplifying circuit, a comparator circuit and a voltage reference circuit; The PD sensor collects PD photocurrent signals of the laser and sends the PD photocurrent signals to the resistor divider circuit; the resistor voltage dividing circuit converts the PD photocurrent signal into a PD voltage signal and then sends the PD voltage signal to the in-phase proportional amplifying circuit; The in-phase proportional amplifying circuit amplifies the PD voltage signal and then transmits the PD voltage signal to one input end of the comparator circuit, the other input end of the comparator circuit is connected with the voltage reference circuit, and the output end of the comparator circuit outputs the processed PD signal.
  2. 2. The PD detection alarm protection circuit of claim 1, wherein the PD sensor is a planar silicon PN photodiode.
  3. 3. The PD detection alarm protection circuit as set forth in claim 1, wherein the resistor divider circuit comprises a resistor R1 and a resistor R3; One end of the resistor R1 is connected with the negative electrode of the PD photocurrent signal, and the other end of the resistor R1 is connected with a power supply VCC; one end of the resistor R3 is grounded, and the other end of the resistor R3 is connected with the positive electrode of the PD photocurrent signal and the input end of the in-phase proportional amplifying circuit.
  4. 4. The PD detection alarm protection circuit as set forth in claim 1, wherein the in-phase proportional amplifier comprises a first operational amplifier, a resistor R4 and a resistor R5; The positive input end of the first operational amplifier is connected with the output end of the resistor divider circuit, the negative input end of the first operational amplifier is grounded after passing through the resistor R4, and the resistor R5 is connected between the negative input end and the output end of the first operational amplifier.
  5. 5. The PD detection alarm protection circuit of claim 4, wherein the first operational amplifier is model SGM8965A-1; a sliding adjustable resistor R2 is also connected between the negative input end of the first operational amplifier and the resistor R4; The power negative input end of the first operational amplifier is grounded, the power positive input end of the first operational amplifier is connected with the power supply end of the power supply and one end of the capacitor C1, and the other end of the capacitor C1 is grounded.
  6. 6. The PD detection alarm protection circuit as set forth in claim 1, wherein the comparator circuit comprises a second operational amplifier, an N-channel enhancement type field effect transistor Q1, a resistor R11 and a resistor R12; the negative input end of the second operational amplifier receives the amplified PD voltage signal output by the in-phase proportional amplifying circuit; The positive input end of the second operational amplifier is connected with the reference voltage Vref output by the voltage reference circuit; The output end of the second operational amplifier is connected with the G pole of the field effect transistor Q1; The S electrode of the field effect tube Q1 is grounded, the D electrode of the field effect tube Q1 is connected with one ends of the resistor R11 and the resistor R12, the other end of the resistor R11 is grounded, the other end of the resistor R12 is connected with a power supply end, and the D electrode of the field effect tube Q1 is used as a port for outputting the processed PD signal.
  7. 7. The PD detection alarm protection circuit of claim 6, wherein the second operational amplifier is of the type SGM8965A-1, and the field effect transistor Q1 is of the type 2N7002; The power negative input end of the second operational amplifier is grounded, the power positive input end of the second operational amplifier is connected with the power supply end of the power supply and one end of the capacitor C2, and the other end of the capacitor C2 is grounded.
  8. 8. The PD detection alarm protection circuit as set forth in claim 6, wherein the voltage reference circuit comprises a voltage reference chip, a voltage dividing circuit and a resistor R13, wherein the voltage dividing circuit comprises a resistor R9 and a resistor R10; one end of the resistor R9 and one end of the resistor R10 are connected with the positive input end of the second operational amplifier, the other end of the resistor R9 is grounded, and the other end of the resistor R10 is connected with the output end of the voltage reference chip; the output end of the voltage reference chip is also connected with a power supply through the resistor R13.
  9. 9. The PD detection alarm protection circuit of claim 8, wherein the voltage reference chip is model LM4040AIM3X or LM4040-N.
  10. 10. The PD detection alarm protection circuit of claim 1, wherein the processed PD signal is input to a high speed FPGA, the high speed FPGA being EP4CE10E22C8N.

Description

PD detection alarm protection circuit of laser instrument Technical Field The utility model relates to the technical field of photoelectric detection lasers, in particular to a PD detection alarm protection circuit of a laser. Background PD (photodiode) converts light energy into an electric signal (photocurrent) in direct proportion to light intensity by receiving part of emitted light (usually led in through a light splitting structure) in the laser, and the current laser PD detection method mainly adopts hardware processing, and enters MCU processing after monostable triggering on PD signals, so that the following defects exist in the traditional scheme: 1. The transimpedance amplifier needs a high-precision feedback element, has high cost and needs to process waveforms, and the speed is suitable for medium-low speed detection. And 2, the MCU detects the PD signal and then controls the driving laser to enable, so that the speed is low and the interference is easy. 3. The multi-stage operational amplifier is connected in series to cause noise superposition and signal to noise ratio reduction. 4. The photosurface of a conventional PD is too small and the sensitivity is low. Accordingly, in view of the above-mentioned drawbacks of the prior art, it is highly desirable to provide a method for processing a signal of a fiber laser PD. Disclosure of utility model Aiming at the technical problems in the prior art, the utility model provides a PD detection alarm protection circuit of a laser. The PD detection alarm protection circuit of the laser comprises a PD sensor, a resistor voltage dividing circuit, an in-phase proportion amplifying circuit, a comparator circuit and a voltage reference circuit; The PD sensor collects PD photocurrent signals of the laser and sends the PD photocurrent signals to the resistor divider circuit; the resistor voltage dividing circuit converts the PD photocurrent signal into a PD voltage signal and then sends the PD voltage signal to the in-phase proportional amplifying circuit; The in-phase proportional amplifying circuit amplifies the PD voltage signal and then transmits the PD voltage signal to one input end of the comparator circuit, the other input end of the comparator circuit is connected with the voltage reference circuit, and the output end of the comparator circuit outputs the processed PD signal. The utility model has the advantages that the cost is reduced, the detection reliability is obviously improved, and the detection response speed is very fast by optimizing the front-stage amplifying architecture and the rear-stage reference design. And can be monitored in real time by an upper computer. The system is particularly suitable for a safety protection system of industrial laser equipment. On the basis of the technical scheme, the utility model can be improved as follows. Further, the PD sensor is a planar silicon PN photodiode. Further, the resistor divider circuit comprises a resistor R1 and a resistor R3; One end of the resistor R1 is connected with the negative electrode of the PD photocurrent signal, and the other end of the resistor R1 is connected with a power supply VCC; one end of the resistor R3 is grounded, and the other end of the resistor R3 is connected with the positive electrode of the PD photocurrent signal and the input end of the in-phase proportional amplifying circuit. Further, the in-phase proportional amplifier comprises a first operational amplifier, a resistor R4 and a resistor R5; The positive input end of the first operational amplifier is connected with the output end of the resistor divider circuit, the negative input end of the first operational amplifier is grounded after passing through the resistor R4, and the resistor R5 is connected between the negative input end and the output end of the first operational amplifier. Further, the model of the first operational amplifier is SGM8965A-1; a sliding adjustable resistor R2 is also connected between the negative input end of the first operational amplifier and the resistor R4; The power negative input end of the first operational amplifier is grounded, the power positive input end of the first operational amplifier is connected with the power supply end of the power supply and one end of the capacitor C1, and the other end of the capacitor C1 is grounded. Further, the comparator circuit comprises a second operational amplifier, an N-channel enhanced field effect transistor Q1, a resistor R11 and a resistor R12; the negative input end of the second operational amplifier receives the amplified PD voltage signal output by the in-phase proportional amplifying circuit; The positive input end of the second operational amplifier is connected with the reference voltage Vref output by the voltage reference circuit; The output end of the second operational amplifier is connected with the G pole of the field effect transistor Q1; The S electrode of the field effect tube Q1 is grounded, the D electrode