Optical power acquisition range automatic switching circuit

Abstract

The utility model discloses an optical power acquisition range automatic switching circuit, and belongs to the technical field of amplification circuits. An automatic switching circuit for optical power acquisition ranges comprises a photoelectric sensor PD1, a current-voltage conversion amplification circuit, a secondary amplification circuit, a comparison circuit and a voltage selector U4. The output voltage of the current-voltage conversion amplification circuit is divided into two paths, one path is connected to an NC1 pin of the voltage selector U4, and the other path is used as the input of the secondary amplification circuit; the output voltage of the secondary amplification circuit is divided into two paths, one path is connected to a NO1 pin of the voltage selector U4, and the other path is used as the input of the comparison circuit; the comparison circuit is used for comparing the output voltage of the secondary amplification circuit with a preset reference voltage, and the output voltage of the comparison circuit is used as the input of an I O pin of the voltage selector U4; and the voltage selector U4 selects to connect the COM end with the NC1 or NO1 channel according to the input of the I O pin, so that automatic switching of the optical power detection range is realized, and the optical power detection range is improved.

Description

Technical Field

[0001] This utility model relates to the field of amplifier circuit technology, and more specifically, to an automatic switching circuit for optical power acquisition range. Background Technology

[0002] Space laser communication is a communication method that uses laser beams as carriers to transmit images, voice, and signals in space. Compared with traditional microwave communication, laser communication has advantages such as high transmission rate, large communication capacity, strong resistance to electromagnetic interference, and high security. Furthermore, its communication terminals are small in size, have low power consumption, and are highly practical. Optical amplifiers are crucial components in space laser communication, amplifying weak input light signals to higher power levels, thereby improving signal transmission distance and quality. This is critical for addressing signal attenuation issues in long-distance fiber optic transmission and optical communication systems. In traditional optical amplifiers, high-gain amplifiers require an input light acquisition range of ≥50dB. Conventional optical power acquisition schemes have a maximum acquisition range of -35dB, requiring amplification using dedicated logarithmic amplifiers. Currently, there are no aerospace-grade logarithmic amplifiers that meet these requirements.

[0003] A search revealed that Chinese patent CN109600122A discloses a variable transimpedance amplifier current-to-voltage conversion circuit. When the output of the secondary amplifier is too small, the host computer switches to a larger transimpedance-to-capacitance pair and checks the output value of the secondary amplifier again. If the output is within a reasonable range, it indicates that the switched transimpedance-to-capacitance pair matches the optical signal of the photodiode PD1. If the output value of the secondary amplifier is still too small, it will continue to switch to a larger transimpedance-to-capacitance pair.

[0004] The patent discloses a scheme for detecting different input light by switching the amplification resistor of a transimpedance amplifier. When the input light signal suddenly increases, the host computer needs more time to judge the signal. During this process, the voltage entering the ADC may exceed the ADC input voltage value, causing damage to the ADC. In view of this, we propose an automatic switching circuit for optical power acquisition range. Utility Model Content

[0005] 1. Technical problems to be solved

[0006] The purpose of this invention is to provide an automatic switching circuit for optical power acquisition range to solve the problems mentioned in the background art.

[0007] 2. Technical Solution

[0008] This utility model is achieved through the following technical solution:

[0009] An automatic switching circuit for optical power acquisition range includes a photoelectric sensor PD1, a current-to-voltage conversion amplifier circuit, a two-stage amplifier circuit, a comparator circuit, and a voltage selector U4. The photoelectric sensor PD1 converts an optical signal into a current signal, and the current signal serves as the input to the current-to-voltage conversion amplifier circuit.

[0010] The output voltage of the current-to-voltage conversion amplifier circuit is divided into two paths: one path is connected to the NC1 pin of the voltage selector U4, and the other path serves as the input of the secondary amplifier circuit.

[0011] The output voltage of the secondary amplifier circuit is divided into two paths: one path is connected to the NO1 pin of the voltage selector U4, and the other path is used as the input of the comparator circuit.

[0012] The comparator circuit is used to compare the output voltage of the secondary amplifier circuit with a preset reference voltage, and the output voltage of the comparator circuit is used as the input of the IO pin of the voltage selector U4.

[0013] The voltage selector U4 selects whether to connect the COM terminal to the NC1 or NO1 channel based on the input of the IO pin.

[0014] As an optional solution to the technical solution of this application, the current-to-voltage conversion amplifier circuit includes an amplifier U2C, a feedback resistor R5 and a filter capacitor C1. The feedback resistor R5 and the filter capacitor C1 are connected across the input -IN pin and the output OUT pin of the amplifier U2C. The photoelectric sensor PD1 is a photodiode, whose anode is connected to the +IN pin of the amplifier U2C and connected to ground GND, and whose cathode is connected to the -IN pin of the amplifier U2C.

[0015] As an optional solution to the technical solution in this application, the secondary amplifier circuit includes an amplifier U3C, a resistor R7, and a resistor R9. The resistor R7 is connected between the input-IN pin and the output-OUT pin of the amplifier U3C, and the resistor R9 is connected between the input-IN pin of the amplifier U3C and ground GND.

[0016] As an optional solution to the technical solution in this application, the comparison circuit includes a comparator UC1, a resistor R8 and a resistor R10, wherein the resistor R8 and the resistor R10 are connected in series, and the input-IN pin of the comparator UC1 is connected between the resistor R8 and the resistor R10.

[0017] As an optional solution to the technical solution in this application, the feedback resistor R5 is 30KΩ.

[0018] As an optional solution to the technical solution in this application, the resistor R7 is 49KΩ and the resistor R9 is 1KΩ.

[0019] As an optional solution to the technical solution in this application, the resistor R8 is 2KΩ and the resistor R10 is 3KΩ.

[0020] 3. Beneficial effects

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] 1) This application expands the optical power detection range using existing aerospace devices and shortens the range switching time, thus avoiding the risks associated with using industrial-grade devices.

[0023] 2) This application realizes the automatic switching of optical power detection range, thereby improving the optical power detection range. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the circuit structure of an automatic switching circuit for optical power acquisition range. Detailed Implementation

[0025] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings.

[0026] Please see Figure 1 This utility model provides an automatic switching circuit for optical power acquisition range, including a photoelectric sensor PD1, a current-to-voltage conversion amplifier circuit, a two-stage amplifier circuit, a comparator circuit, and a voltage selector U4. The photoelectric sensor PD1 converts the optical signal into a current signal, and the current signal serves as the input to the current-to-voltage conversion amplifier circuit.

[0027] The output voltage of the current-to-voltage conversion amplifier circuit is divided into two paths: one path is connected to the NC1 pin of the voltage selector U4, and the other path serves as the input of the secondary amplifier circuit.

[0028] The output voltage of the secondary amplifier circuit is divided into two paths: one path is connected to the NO1 pin of the voltage selector U4, and the other path is used as the input of the comparator circuit.

[0029] The comparator circuit is used to compare the output voltage of the secondary amplifier circuit with a preset reference voltage, and the output voltage of the comparator circuit is used as the input of the IO pin of the voltage selector U4.

[0030] The voltage selector U4 selects whether to connect the COM terminal to the NC1 or NO1 channel based on the input of the IO pin.

[0031] Preferably, the current-to-voltage conversion amplifier circuit includes an amplifier U2C, a feedback resistor R5, and a filter capacitor C1. The feedback resistor R5 is 30KΩ. The feedback resistor R5 and the filter capacitor C1 are connected across the input -IN pin and the output OUT pin of the amplifier U2C. The photoelectric sensor PD1 is a photodiode, whose anode is connected to the +IN pin of the amplifier U2C and connected to ground GND, and whose cathode is connected to the -IN pin of the amplifier U2C.

[0032] Preferably, the secondary amplifier circuit includes an amplifier U3C, a resistor R7, and a resistor R9. The resistor R7 is 49KΩ, the resistor R9 is 1KΩ, the resistor R7 is connected between the input-IN pin and the output-OUT pin of the amplifier U3C, and the resistor R9 is connected between the input-IN pin of the amplifier U3C and ground GND.

[0033] Preferably, the comparison circuit includes a comparator UC1, resistors R8 and R10, wherein resistor R8 is 2KΩ, resistor R10 is 3KΩ, resistors R8 and R10 are connected in series, and the input-IN pin of comparator UC1 is connected between resistors R8 and R10.

[0034] Working principle:

[0035] After receiving the optical signal, the photoelectric sensor PD1 converts it into a current signal using the formula: I = 0.95 A / W. When the input light intensity is -65 dBm to -26.8 dBm, the output voltage of amplifier U2C ranges from 0.009 mV to 59.545 mV. Amplifier U3C has a gain of 50, and the output voltage of amplifier U2C, after being amplified by amplifier U3C, ranges from 0.45 mV to 2977 mV.

[0036] When the output voltage of amplifier U3C is less than 3V, comparator UC1 outputs a high level, and the channel selection input IN1 and IO output of voltage selector U4 are both high. Voltage selector U4 connects NC1 and COM terminals. Amplifier U2C output is connected to NO1 and then left floating. Amplifier U3C output is connected to NC1 and finally connected to the ADC input through COM terminal. That is, when IO is high, the program determines to use amplifier U3C input and executes the program to calculate the input optical power.

[0037] When the input light is -26.6dBm to -10dBm, the output voltage of amplifier U2C is 60.93mV to 2850mV. After being amplified by amplifier U3C, the output voltage of amplifier U2C is 3046mV to 3900mV. When the output of amplifier U3C is greater than 3V, the output of amplifier U1C is low, and the channel selection input IN1 and IO output of voltage selector U4 are both low. The voltage selector connects NO1 and COM terminals. After the output of amplifier U2C is connected to NO1, it is finally connected to the ADC input through the COM terminal. That is, when IO is low, the program determines to use amplifier U2C input to calculate the input optical power. This realizes the function of automatic range switching of input optical power acquisition through hardware and software cooperation.

Claims

1. An automatic switching circuit for optical power acquisition range, characterized in that: It includes a photoelectric sensor PD1, a current-to-voltage conversion amplifier circuit, a two-stage amplifier circuit, a comparator circuit, and a voltage selector U4. The photoelectric sensor PD1 converts an optical signal into a current signal, and the current signal serves as the input to the current-to-voltage conversion amplifier circuit. The output voltage of the current-to-voltage conversion amplifier circuit is divided into two paths: one path is connected to the NC1 pin of the voltage selector U4, and the other path serves as the input of the secondary amplifier circuit. The output voltage of the secondary amplifier circuit is divided into two paths: one path is connected to the NO1 pin of the voltage selector U4, and the other path is used as the input of the comparator circuit. The comparator circuit is used to compare the output voltage of the secondary amplifier circuit with a preset reference voltage, and the output voltage of the comparator circuit is used as the input of the IO pin of the voltage selector U4. The voltage selector U4 selects whether to connect the COM terminal to the NC1 or NO1 channel based on the input of the IO pin.

2. The automatic switching circuit for optical power acquisition range according to claim 1, characterized in that: The current-to-voltage conversion amplifier circuit includes an amplifier U2C, a feedback resistor R5, and a filter capacitor C1. The feedback resistor R5 and the filter capacitor C1 are connected across the input -IN pin and the output OUT pin of the amplifier U2C. The photoelectric sensor PD1 is a photodiode, whose anode is connected to the +IN pin of the amplifier U2C and connected to ground GND, and whose cathode is connected to the -IN pin of the amplifier U2C.

3. The automatic switching circuit for optical power acquisition range according to claim 1, characterized in that: The secondary amplifier circuit includes amplifier U3C, resistor R7 and resistor R9. Resistor R7 is connected between the input-IN pin and the output-OUT pin of amplifier U3C, and resistor R9 is connected between the input-IN pin of amplifier U3C and ground GND.

4. The automatic switching circuit for optical power acquisition range according to claim 1, characterized in that: The comparison circuit includes a comparator UC1, resistors R8 and R10, with resistors R8 and R10 connected in series. The input-IN pin of the comparator UC1 is connected between resistors R8 and R10.

5. The automatic switching circuit for optical power acquisition range according to claim 2, characterized in that: The feedback resistor R5 is 30KΩ.

6. The automatic switching circuit for optical power acquisition range according to claim 3, characterized in that: The resistor R7 is 49KΩ and the resistor R9 is 1KΩ.

7. The automatic switching circuit for optical power acquisition range according to claim 4, characterized in that: The resistor R8 is 2KΩ and the resistor R10 is 3KΩ.

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