A device for detecting minute currents on laser seekers

Abstract

A detection device for tiny current on a laser seeker includes a current-to-voltage transimpedance amplifier circuit, a gain control amplifier circuit, a digital-to-analog conversion circuit, and a power supply circuit; the current-to-voltage transimpedance amplifier circuit is used to convert the weak current signal generated by the diffusely reflected laser pulse signal into a voltage signal; the gain control amplifier circuit is used to further amplify the voltage signal within an optional range; the digital-to-analog conversion circuit is used to dynamically adjust the gain of the gain control amplifier circuit; the digital-to-analog conversion circuit outputs an adjustment analog quantity and sends it to the gain control amplifier circuit, and the gain control amplifier circuit receives the adjustment analog quantity output by the digital-to-analog conversion circuit and dynamically adjusts the amplification factor of the output signal. The present invention can avoid saturation when the laser pulse signal enters the analog-to-digital converter, so that the laser seeker can track the target more quickly and accurately.

Description

Technical Field

[0001] The invention belongs to the field of tiny current amplification detection, and relates to a tiny current detection device suitable for a laser seeker. Background Art

[0002] The laser seeker generates guidance information by receiving diffusely reflected laser pulse signals and then performing a series of related processing, so that the missile can accurately strike the target according to a certain rule. Therefore, it is particularly important to be able to accurately receive diffusely reflected laser signals. The received laser signal will enter the entire seeker system as a weak current signal after passing through the sensor. Therefore, it is necessary to process the weak current signal so that the seeker system can generate guidance information more reliably and accurately. After the traditional laser seeker processes the diffusely reflected laser pulse signal, signal saturation is prone to occur when entering the analog-to-digital converter, and the target is easily lost during terminal guidance, which greatly reduces the accuracy and reliability of striking the target. Summary of the invention

[0003] The purpose of the present invention is to address the problem in the above-mentioned prior art that the laser seeker has low processing accuracy for the diffusely reflected laser pulse signal, and to provide a detection device suitable for a tiny current on a laser seeker to avoid saturation when the laser pulse signal enters the analog-to-digital converter, so that the laser seeker can track the target more quickly and accurately.

[0004] In order to achieve the above object, the present invention has the following technical solutions:

[0005] A detection device for tiny current on a laser seeker comprises a current-to-voltage transimpedance amplifier circuit, a gain control amplifier circuit, a digital-to-analog conversion circuit and a power supply circuit; the current-to-voltage transimpedance amplifier circuit is used to convert a weak current signal generated by a diffusely reflected laser pulse signal into a voltage signal; the gain control amplifier circuit is used to further amplify the voltage signal generated by the current-to-voltage transimpedance amplifier circuit within an optional range; the digital-to-analog conversion circuit is used to dynamically adjust the gain of the gain control amplifier circuit; according to the voltage signal further amplified by the gain control amplifier circuit, the digital-to-analog conversion circuit outputs an adjustment analog quantity and sends it to the gain control amplifier circuit, and the gain control amplifier circuit receives the adjustment analog quantity output by the digital-to-analog conversion circuit and dynamically adjusts the amplification factor of the output signal; the power supply circuit is used to supply power to the current-to-voltage transimpedance amplifier circuit, the gain control amplifier circuit and the digital-to-analog conversion circuit.

[0006] Preferably, in an embodiment of the detection device for tiny currents on a laser seeker of the present invention, the current-to-voltage transimpedance amplifier circuit includes a TIA amplifier, pin 2 of the TIA amplifier is connected to a capacitor C7 for isolating a DC component in an input signal, and pin 6 of the TIA amplifier is an output signal terminal; a feedback capacitor C8 and a feedback resistor R4 are connected in parallel between pins 2 and 6 of the TIA amplifier, a high-precision resistor is selected for the feedback resistor R4 to convert current and voltage, and the feedback capacitor C8 is used to provide a release loop for high-frequency noise; pin 3 of the TIA amplifier is directly grounded, a noise filter capacitor C11 and a noise filter capacitor C12 are arranged in parallel between pin 4 of the TIA amplifier and the ground wire, and a noise filter capacitor C9 and a noise filter capacitor C10 are arranged in parallel between pin 7 of the TIA amplifier and the ground wire.

[0007] Preferably, in an embodiment of the present invention suitable for detecting a tiny current on a laser seeker, the gain control amplifier circuit includes a controllable gain amplifier, pin 3 of the controllable gain amplifier is connected to the voltage signal output end of the current-to-voltage transresistance amplifier circuit, pin 7 is the output signal end, and pin 1 is connected to the analog output end of the digital-to-analog conversion circuit. The voltage difference between pin 2 and pin 1 of the controllable gain amplifier determines the amplification factor corresponding to the input signal, and capacitors C35 and C42 for isolating the DC components of the input and output signals are respectively arranged on the circuits of pins 3 and 7.

[0008] Preferably, in an embodiment of the device for detecting tiny currents on a laser seeker of the present invention, the gain control amplifier circuit is controlled by the analog quantity adjusted by the output of the digital-to-analog conversion circuit, and can provide selectable amplification factors of -10db to +30db, 0db to +40db, and +10db to +50db.

[0009] Preferably, in an embodiment of the present invention, the detection device for tiny currents on a laser seeker is used, the interface of the digital-to-analog conversion circuit adopts a serial bus SPI interface, the circuit distinguishes between digital ground and analog ground and performs single-point grounding respectively, the digital-to-analog conversion circuit includes a digital-to-analog converter with a reference voltage integrated inside the chip, pin 1 of the digital-to-analog converter is connected to an alarm indicator light, and an alarm indication is given when the internal parameters of the chip exceed the rated value, and pin 7 of the digital-to-analog converter is connected to a gain control amplifier circuit, which is used to output an adjusted analog quantity and send it to the gain control amplifier circuit.

[0010] Preferably, in an embodiment of the present invention, the detection device for tiny currents on a laser seeker is used, the power supply circuit outputs positive and negative 5V voltages, the input voltage can be selected from 2.6V to 50V, a Buck circuit is selected for design when a +5V voltage is output, and an Invert circuit is selected for design when a -5V voltage is output.

[0011] Preferably, in an embodiment of the device for detecting tiny currents on a laser seeker of the present invention, the power supply circuit is provided with a resistor for setting the switching frequency inside the circuit, a plurality of resistors for feeding feedback voltage back to the chip to dynamically adjust the set output voltage, and a plurality of capacitors for reducing the output voltage ripple.

[0012] Compared with the prior art, the present invention has the following beneficial effects: a current-to-voltage transimpedance amplifier circuit is used as the first-stage amplifier circuit, a gain control amplifier circuit is used as the second-stage amplifier circuit, and a digital-to-analog conversion circuit is used to adjust the gain of the second-stage amplifier circuit, so that a wider dynamic range is achieved without causing saturation when output to the next stage. The present invention introduces an adjustment mechanism to avoid signal saturation when the signal enters the analog-to-digital converter, and has a better dynamic adjustment range. The present invention can effectively amplify the tiny current on the laser seeker, thereby enabling the laser seeker to track the target more quickly and accurately. Receiving and processing diffusely reflected laser pulse signals is more flexible, which is beneficial to improving the reliability of the entire system.

[0013] Furthermore, the design of each circuit module of the present invention can effectively control voltage ripple, reduce the introduction of noise, avoid mutual interference between digital ground and analog ground, reduce design cost and improve circuit stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The overall circuit structure block diagram of the current detection device of the present invention;

[0015] Figure 2 Schematic diagram of the current-to-voltage transimpedance amplifier circuit of the present invention;

[0016] Figure 3 The simulation result diagram of the current-to-voltage transimpedance amplifier circuit of the present invention;

[0017] Figure 4 Schematic diagram of the gain control amplifier circuit of the present invention;

[0018] Figure 5 A simulation result diagram of the gain control amplifier circuit of the present invention;

[0019] Figure 6 Schematic diagram of the digital-to-analog conversion circuit of the present invention;

[0020] Figure 7 A schematic diagram of a power supply circuit of the present invention;

[0021] Figure 8 The simulation result diagram of the power supply circuit of the present invention;

[0022] In the attached figure: 1-current-to-voltage transimpedance amplifier circuit; 2-gain control amplifier circuit; 3-digital-to-analog conversion circuit; 4-power supply circuit. DETAILED DESCRIPTION

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0024] See also Figure 1 The present invention is applicable to a detection device for a tiny current on a laser seeker, and the overall structure includes a current-to-voltage transimpedance amplifier circuit 1, a gain control amplifier circuit 2, a digital-to-analog conversion circuit 3 and a power supply circuit 4.

[0025] Among them, the power supply circuit 4 provides the voltage and current required for the entire operation to the current-to-voltage transimpedance amplifier circuit 1, the gain control amplifier circuit 2, and the digital-to-analog conversion circuit 3. The current-to-voltage transimpedance amplifier circuit 1 transmits the converted small voltage signal to the gain control amplifier circuit 2 of the next stage. The gain control amplifier circuit 2 continues to amplify the signal input from the previous stage, and then sends the output signal to the digital-to-analog conversion circuit 3. After being processed by the CPU software, the output signal is given to the digital-to-analog conversion circuit 3. The digital-to-analog conversion circuit 3 outputs the output analog quantity to the gain control amplifier circuit 2. The gain control amplifier circuit 2 dynamically adjusts the amplification factor of the output signal according to the size of the analog quantity received from the digital-to-analog conversion circuit 3.

[0026] See also Figure 2-3 The current-to-voltage transimpedance amplifier circuit 1 of the present invention is provided with a TIA amplifier. When selecting the amplifier, it is necessary to consider the bias current, noise, power supply range and type of the device, and select the appropriate device bandwidth, power supply noise suppression ratio, common mode voltage suppression ratio, etc. according to the bandwidth of the input signal to adapt to the processing of the entire system. Figure 2 The power supply of the current-to-voltage transimpedance amplifier circuit 1 of the present invention is powered by a dual power supply. It should be noted that a small signal is processed, so the power supply ripple must be properly controlled, otherwise noise will be introduced into the system, affecting the authenticity of the system output signal. The functions of the capacitors C9, C10, C11, and C12 in the circuit are to filter the noise on the power supply and reduce the ripple of the power supply system. Capacitor C8 and resistor R4 are the feedback system of the circuit, wherein resistor R4 needs to select a high-precision resistor for current-voltage conversion, and capacitor C8 provides a release loop for high-frequency noise. The cutoff frequency of the filter circuit they form is 1 / 2*pi*r*c, so as not to affect the output signal quality of the system. Capacitor C7 in the circuit isolates the DC component in the input signal.

[0027] See also Figure 4 , Figure 5For the gain control amplifier circuit 2 of the present invention, the gain control range is different in different situations for signal amplification. Specifically, the capacitor C40 and the resistor R14 are matched, and the available amplification factors are -10db to +30db, 0db to +40db, and +10db to +50db. The voltage difference between pin 1 and pin 2 on the chip determines the amplification factor corresponding to the input signal. The capacitor C35 and the capacitor C42 isolate the DC components of the input and output signals.

[0028] See also Figure 6 In the digital-to-analog conversion circuit 3 of the present invention, its digital circuit interface adopts a serial bus SPI interface, and the resistors R16, R15, and R18 in the circuit are 33Ω resistors connected in series, the purpose of which is to reduce signal reflection and improve signal integrity. The digital ground and the analog ground need to be separated in the circuit, and they are grounded at a single point to reduce interference between different grounds. The reference voltage has been integrated inside the chip, so the circuit design at the reference voltage can be reduced during circuit design, reducing the design cost while improving the stability of the circuit. Pin 1 of the chip outputs a low level when the temperature and other signal quantities inside the chip exceed the rated value, which is used for alarm indication so that the user can perform timely processing to avoid irreparable damage to the chip. Pin 7 of the chip is connected to the gain control amplifier circuit of the previous level to dynamically adjust the gain.

[0029] See also Figure 7-8 In the power supply circuit 4 of the present invention, the power supply circuit outputs positive and negative 5V voltages, the input voltage can be selected from 2.6V to 50V, the Buck circuit is selected for design at +5V output, and the Invert circuit is selected for design at -5V output. R4 in the circuit sets the switching frequency inside the circuit, D1 and D2 need to select faster diodes, such as Schottky diodes, etc., resistors R7, R8, R5, and R6 send feedback voltage back to the chip to dynamically adjust the set output voltage, and capacitors C12, C13, C10, and C11 are filter capacitors to reduce the ripple of the output voltage.

[0030] Through verification, the above-mentioned detection device of the present invention applicable to the tiny current on the laser seeker can more flexibly receive and process the diffusely reflected laser, so that the reliability of the whole system is improved. The present invention introduces an adjustment mechanism to avoid the signal saturation phenomenon when the signal enters the analog-to-digital converter, and has a better dynamic adjustment range. Through the present invention, the tiny current on the laser seeker can be effectively amplified, so that the laser seeker can track the target more quickly and accurately.

[0031] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A detection device for tiny current on a laser seeker, characterized in that: The invention comprises a current-to-voltage transimpedance amplifier circuit (1), a gain control amplifier circuit (2), a digital-to-analog conversion circuit (3) and a power supply circuit (4); the current-to-voltage transimpedance amplifier circuit (1) is used to convert a weak current signal generated by a diffusely reflected laser pulse signal into a voltage signal; the gain control amplifier circuit (2) is used to further amplify the voltage signal generated by the current-to-voltage transimpedance amplifier circuit (1) within an optional range; the digital-to-analog conversion circuit (3) is used to dynamically adjust the gain of the gain control amplifier circuit (2); according to the voltage signal further amplified by the gain control amplifier circuit (2), the digital-to-analog conversion circuit (3) outputs an adjustment analog quantity and sends it to the gain control amplifier circuit (2); the gain control amplifier circuit (2) receives the adjustment analog quantity output by the digital-to-analog conversion circuit (3) and dynamically adjusts the amplification factor of the output signal; the power supply circuit (4) The electric circuit (4) is used to supply power to the current-to-voltage transimpedance amplifier circuit (1), the gain control amplifier circuit (2) and the digital-to-analog conversion circuit (3); the gain control amplifier circuit (2) comprises a controllable gain amplifier, the 3rd pin of the controllable gain amplifier is connected to the voltage signal output end of the current-to-voltage transimpedance amplifier circuit (1), the 7th pin is the output signal end, the 1st pin is connected to the analog output end of the digital-to-analog conversion circuit (3), the voltage difference between the 2nd pin and the 1st pin of the controllable gain amplifier determines the amplification factor corresponding to the input signal, and the circuits of the 3rd pin and the 7th pin are respectively provided with capacitors C35 and C42 for isolating the DC components of the input and output signals; the power supply circuit (4) is provided with a resistor for setting the switching frequency inside the circuit, a plurality of resistors for feeding feedback voltage back to the chip to dynamically adjust the set output voltage, and a plurality of capacitors for reducing the output voltage ripple.

2. The device for detecting minute currents on a laser seeker according to claim 1, characterized in that: The current-to-voltage transimpedance amplifier circuit (1) comprises a TIA amplifier, wherein pin 2 of the TIA amplifier is connected to a capacitor C7 for isolating a DC component in an input signal, and pin 6 of the TIA amplifier is an output signal terminal; a feedback capacitor C8 and a feedback resistor R4 are connected in parallel between pins 2 and 6 of the TIA amplifier, wherein a high-precision resistor is selected for the feedback resistor R4 to perform current-voltage conversion, and the feedback capacitor C8 is used to provide a release loop for high-frequency noise; pin 3 of the TIA amplifier is directly grounded, a noise filter capacitor C11 and a noise filter capacitor C12 are connected in parallel between pin 4 of the TIA amplifier and the ground line, and a noise filter capacitor C9 and a noise filter capacitor C10 are connected in parallel between pin 7 of the TIA amplifier and the ground line.

3. The device for detecting minute currents on a laser seeker according to claim 1, characterized in that: The gain control amplifier circuit (2) is controlled by the analog quantity outputted by the digital-to-analog conversion circuit (3), and can provide selectable amplification factors of -10db to +30db, 0db to +40db, and +10db to +50db.

4. The device for detecting minute currents on a laser seeker according to claim 1, characterized in that: The interface of the digital-to-analog conversion circuit (3) adopts a serial bus SPI interface, and the circuit distinguishes between a digital ground and an analog ground and performs single-point grounding respectively. The digital-to-analog conversion circuit (3) includes a digital-to-analog converter having a reference voltage integrated inside the chip. Pin 1 of the digital-to-analog converter is connected to an alarm indicator light, and an alarm indication is given when the internal parameters of the chip exceed the rated value. Pin 7 of the digital-to-analog converter is connected to a gain control amplifier circuit (2) and is used to output an adjusted analog quantity and send it to the gain control amplifier circuit (2).

5. The device for detecting minute currents on a laser seeker according to claim 1, characterized in that: The power supply circuit (4) outputs positive and negative 5V voltages, and the input voltage can be selected from 2.6V to 50V. When the +5V voltage is output, a Buck circuit is selected for design, and when the -5V voltage is output, an Invert circuit is selected for design.

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