Multi-channel optical power detection circuit

Abstract

The utility model discloses a multichannel optical power detection circuit, include: low noise linear voltage stabilizing power supply is used for providing stable and low noise power supply voltage, laser detection processing module is connected with the output of low noise linear voltage stabilizing power supply, is used for processing multichannel laser light signal, laser detection processing module includes at least six way laser light signal detection unit, and four way is continuous light signal detection unit, two way is pulse light signal detection unit, continuous light signal detection unit includes laser light signal input detection unit, amplifying unit, filter unit and output interface unit in proper order, pulse light signal detection unit includes laser light signal input detection unit, amplifying unit, peak value holding unit, filter unit and output interface unit in proper order, the utility model discloses by adopting low noise linear voltage stabilizing power supply and high bandwidth peak value holding circuit, has improved the response speed and precision of optical power detection significantly, especially applicable to the measurement of low pulse width light signal, has strengthened the anti -jamming capability and stability of system simultaneously.

Description

Technical Field

[0001] This utility model belongs to the field of detection circuit technology, specifically relating to a multi-channel optical power detection circuit. Background Technology

[0002] In existing technologies, optical power detection circuits often struggle to balance high bandwidth and low noise requirements. Photodetector modules explicitly provide bandwidth-noise trade-off curves in their datasheets. Users must select a high-bandwidth mode to measure high-speed pulse signals, but this typically introduces higher noise floor. Conversely, selecting a low-noise mode significantly reduces bandwidth, making it impossible to accurately respond to nanosecond or picosecond laser pulses, leading to signal distortion and a significantly lower measured peak power than the true value. This is especially problematic when processing low-pulse-width optical signals, where signal distortion and decreased accuracy are common. Traditional peak-hold circuits use general-purpose operational amplifiers paired with ordinary rectifier diodes and energy storage capacitors. However, the presence of large parasitic capacitances and noise interference results in slow response times, failing to meet the demands of high-precision measurements. Furthermore, most detection circuits use switching power supplies, which have higher ripple compared to linear power supplies, impacting system stability. Summary of the Invention

[0003] Based on the problems existing in the background technology, the purpose of this utility model is to design an optical power detection circuit that can achieve high bandwidth, low noise, fast response and good anti-interference ability, so as to improve the accuracy and reliability of optical signal detection.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: The multi-channel optical power detection circuit includes: The low-noise linear regulated power supply circuit has a first-stage LC filter in the front stage and a first-stage LC filter and a first-stage common-mode filter in the output stage to provide a stable and low-noise power supply voltage. The laser detection and processing module is connected to the output terminal of the low-noise linear regulated power supply circuit and is used to process multiple laser optical signals. The laser detection and processing module includes at least six laser light signal detection units, of which four are continuous light signal detection units and two are pulsed light signal detection units. The continuous light signal detection unit includes, in sequence, a laser light signal input detection unit, a first-stage amplification unit, a filtering unit, a second-stage amplification unit, and an output interface unit. The pulsed light signal detection unit includes, in sequence, a laser light signal input detection unit, a first-stage amplification unit, a peak hold unit, a filtering unit, a second-stage amplification unit, and an output interface unit.

[0005] Furthermore, the low-noise linear regulated power supply includes a voltage regulation unit and a filtering unit.

[0006] Furthermore, the amplification unit includes a single-stage non-inverting amplifier circuit.

[0007] Furthermore, the peak hold unit includes a single-stage non-inverting amplifier circuit, a Schottky diode, and an energy storage capacitor.

[0008] Furthermore, the filtering unit includes a first-order RC filter circuit.

[0009] Furthermore, the output interface unit is used to output the processed signal to an external device.

[0010] The above technical solution can achieve the following beneficial effects: This invention significantly improves the response speed and accuracy of optical power detection by employing a low-noise linear regulated power supply and a high-bandwidth peak hold circuit, making it particularly suitable for measuring low pulse width optical signals. It also enhances the system's anti-interference capability and stability. Attached Figure Description

[0011] Figure 1 This is an overall diagram of a multi-channel optical power detection circuit.

[0012] Figure 2 This is an enlarged view of the optical detection and acquisition circuit 1.

[0013] Figure 3 This is an enlarged view of the optical detection and acquisition circuit 2.

[0014] Figure 4 This is an enlarged view of the optical detection and acquisition circuit 3.

[0015] Figure 5 This is an enlarged view of the optical detection and acquisition circuit 4.

[0016] Figure 6 This is an enlarged view of the optical detection and acquisition circuit 5.

[0017] Figure 7 This is an enlarged view of the optical detection and acquisition circuit 6. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings: like Figure 1-7As shown, a multi-channel optical power detection circuit based on a high-bandwidth peak-hold circuit, a low-noise linear regulated power supply, and a laser detection and processing module are disclosed. The low-noise linear regulated power supply includes a voltage regulation unit and a filtering unit. The laser detection and processing module includes six laser optical signal detection units, including four continuous detection units and two pulse detection units. The continuous detection unit includes a laser optical signal input detection unit, an amplification unit, a filtering unit, and an output interface unit. The pulse detection unit includes a laser optical signal input detection unit, an amplification unit, a peak-hold unit, a filtering unit, and an output interface unit. The output terminal of the low-noise linear regulated power supply is connected to the laser detection and processing module. The amplification unit includes a first-stage non-inverting amplifier circuit, the peak-hold unit includes a first-stage non-inverting amplifier circuit, a Schottky diode, and an energy storage capacitor, and the filtering unit includes a first-order RC filter circuit. The multi-channel optical power detection circuit based on a high-bandwidth peak-hold circuit provided by this embodiment of the invention can measure optical power under low pulse width and improve the anti-interference characteristics of the power supply.

[0019] Figure 1 The diagram illustrates the specific photodetector acquisition circuit and low-noise linear regulated power supply circuit for a six-channel laser light signal detection unit. Photodetector acquisition circuits 1, 2, 3, and 4 are the specific circuits for a four-channel continuous detection unit, including a laser light signal input detection unit, an amplification unit, a filtering unit, and an output interface unit, corresponding to the laser light signal input terminal, amplification circuit, filtering circuit, and output interface terminal. The photodetector acquisition circuits for the four continuous detection units are identical, differing only in their markings. Taking photodetector acquisition circuit 1 as an example, the left input section: D2 is a photodiode, operating in reverse bias. When continuously illuminated, photons excite the PN junction to generate a photocurrent; the greater the light intensity, the larger the photocurrent, achieving the conversion from optical signal to electrical signal. U6A constitutes a transimpedance amplifier circuit (current-to-voltage conversion). The photocurrent flows in from the inverting input terminal (pin 2). Due to "virtual short" and "virtual open," the potential of the inverting terminal is approximately equal to that of the non-inverting terminal (grounded via voltage divider R31 and R44, with a fixed potential). The output voltage is proportional to the photocurrent, with the ratio determined by the feedback resistor R21 (15kΩ). C34 (100pF) is used for phase compensation and suppression of self-oscillation. R30 (5.1kΩ) and C35 (104, i.e., 0.1μF) form a low-pass filter circuit to filter out high-frequency noise in the U6A output signal, making the signal smoother and easier for subsequent processing. U6B is a non-inverting proportional amplifier circuit. The filtered signal is connected to the non-inverting input terminal, with feedback resistor R3 (10kΩ) and input resistor R2 (10kΩ). The amplified signal passes through an RC circuit composed of R9 (10kΩ) and C18 (105, i.e., 1μF) (which can be further filtered or impedance matched) and is output to the ADC1 port. At this time, the voltage signal corresponds to the incident light power. After the ADC acquires this voltage, the optical power can be calculated by digital circuitry.

[0020] First-stage amplifier circuit (U6A section): This is a transimpedance amplifier circuit. U6A constitutes a transimpedance amplifier circuit (current-to-voltage conversion). The photocurrent flows in from the inverting input terminal (pin 2). Due to the "virtual short" and "virtual open" conditions, the potential of the inverting terminal is approximately equal to that of the non-inverting terminal. The output voltage is proportional to the photocurrent, and the ratio is determined by the feedback resistor R21 (15kΩ). C34 (100pF) is used for phase compensation and suppression of self-oscillation.

[0021] The filter circuit consists of R30 (5.1kΩ) and C35 (104, i.e. 0.1μF) forming a low-pass filter circuit to filter out high-frequency noise in the output signal of U6A, making the signal smoother and easier for subsequent processing.

[0022] The second-stage amplifier circuit, U6B, is a non-inverting proportional amplifier circuit. The non-inverting input terminal is connected to the filtered signal. The feedback resistor R3 (10kΩ) and the input resistor R2 (10kΩ) further amplify the signal to match the voltage range acquired by the ADC.

[0023] The amplified signal, after passing through a secondary filter circuit, is further filtered or impedance matched by an RC circuit consisting of R9 (10kΩ) and C18 (105, i.e., 1μF) and output to the ADC1 port. At this point, the voltage signal corresponds to the incident light power. After the ADC acquires this voltage, the optical power can be calculated using digital circuitry.

[0024] The pulse detection unit includes a laser light signal input detection unit, an amplification unit, a peak hold unit, a filtering unit, and an output interface unit. The light detection and acquisition circuits 5 and 6 are the specific circuits for the two pulse detection units. Taking the light detection and acquisition circuit 5 as an example: Input section: D4 is a photodiode, operating in reverse bias. When light shines on the PN junction of the photodiode, the energy of the photons excites the carriers within the PN junction, generating a photocurrent. The greater the light intensity, the greater the photocurrent generated, thus realizing the function of converting the light signal into an electrical signal. D4 is connected to an operational amplifier U7A, forming a current-to-voltage conversion circuit (transimpedance amplifier circuit). The photocurrent flows in from the inverting input terminal (pin 2) of U7A. Due to the "virtual short" and "virtual open" characteristics of the operational amplifier... According to Ohm's law, the output voltage of U7A is proportional to the input photocurrent, with the proportionality coefficient determined by the feedback resistor R16 (15kΩ). This amplifies the weak photocurrent into a voltage signal. Meanwhile, C20 (100pF) provides phase compensation and suppresses self-oscillation. The output voltage of U7A, along with U8A, Schottky diode D5, discharge resistor R45, and energy storage C23, forms a peak hold circuit. This circuit holds the peak value of the pulse signal converted from the previous stage's detection and transmits it to the next stage, the secondary amplification unit (U8B). Finally, it is output to the ADC5 interface through an RC filter circuit composed of R41 and C25.

[0025] Pre-amplifier photoelectric conversion: D4 is a photodiode, operating in reverse bias. When light shines on the PN junction of the photodiode, the energy of the photons excites the carriers within the PN junction, generating a photocurrent. The greater the light intensity, the greater the photocurrent, thus converting the optical signal into an electrical signal. U7A constitutes a current-to-voltage conversion circuit (transimpedance amplifier circuit). The photocurrent flows into the inverting input terminal (pin 2) of U7A. Due to the "virtual short" and "virtual open" characteristics of the operational amplifier, the potential at the inverting input terminal is approximately equal to the potential at the non-inverting input terminal (the non-inverting input terminal is grounded after voltage division through R38 and R39, and its potential is fixed). According to Ohm's law, the output voltage of U7A is proportional to the input photocurrent, and the proportionality coefficient is determined by the feedback resistor R16 (15kΩ), realizing the amplification process of converting the weak photocurrent into a voltage signal. At the same time, C20 (100pF) plays a role in phase compensation and suppressing self-oscillation.

[0026] Peak Hold: The peak hold circuit, composed of U8A and diodes, can capture and hold the peak value of the input signal. When the input signal reaches its peak value, the diode conducts, and the capacitor charges to the peak voltage; subsequently, when the input signal decreases, the diode turns off, and the capacitor holds the peak voltage, thus achieving the acquisition and holding of the optical signal peak value.

[0027] Post-processing and filtering: The U8B further processes the signal after peak hold (such as amplification and shaping) to ensure the signal meets the requirements of analog-to-digital conversion (ADC). Finally, the signal passes through a filter circuit composed of R41 and C25 to remove high-frequency interference and other noise, resulting in a stable and clean signal output to ADC5 for analog-to-digital conversion and subsequent signal acquisition and analysis.

[0028] The above descriptions are all preferred embodiments of this utility model. For those skilled in the art, any modifications to this utility model in various equivalent forms without departing from the principle of this utility model shall fall within the protection scope of the appended claims.

Claims

1. A multi-channel optical power detection circuit, characterized by: include: The low-noise linear regulated power supply has a first-stage LC filter in the front stage and a first-stage LC filter and a first-stage common-mode filter circuit in the output stage, which are used to provide a stable and low-noise power supply voltage for the subsequent optical power detection circuit. The laser detection and processing module is connected to the output terminal of the low-noise linear regulated power supply and is used to process multiple laser light signals. The laser detection and processing module includes at least six laser light signal detection units, of which four are continuous light signal detection units and two are pulsed light signal detection units. The continuous light signal detection unit includes, in sequence, a laser light signal input detection unit, an amplification unit, a filtering unit, and an output interface unit. The pulsed light signal detection unit includes, in sequence, a laser light signal input detection unit, an amplification unit, a peak hold unit, a filtering unit, and an output interface unit.

2. The multi-channel optical power detection circuit of claim 1, wherein: The low-noise linear regulated power supply includes a voltage regulation unit and a filtering unit.

3. The multi-channel optical power detection circuit of claim 1, wherein: The amplification unit includes a single-stage inverting amplifier circuit.

4. The multi-channel optical power detection circuit of claim 1, wherein: The peak hold unit includes a single-stage non-inverting amplifier circuit, a Schottky diode, and a storage capacitor.

5. The multi-channel optical power detection circuit of claim 1, wherein: The filtering unit includes a first-order RC filter circuit.

6. The multi-channel optical power detection circuit of claim 1, wherein: The output interface unit is used to output the processed signal to an external device.

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