CN103364614B - Self-adaptation wide-range current/voltage conversion equipment - Google Patents

Abstract

The invention relates to an adaptive wide-range current-voltage conversion circuit used for reading out the front end of a current output type detector. It is characterized in that it includes four input high-speed switching circuits respectively connected to the shielded input current signal I _in , and each input high-speed switching circuit is sequentially connected in series with the current-voltage conversion circuit and the output high-speed switching circuit, and then connected in parallel with each other, and then amplified with the inverting phase It is connected with the voltage follower, and the voltage signal output by the inverting amplification and the voltage follower is divided into three channels, one is an analog voltage output, and the other two are respectively connected to the control logic circuit through the high-speed low-threshold discrimination circuit and the high-speed high-threshold discrimination circuit to control The logic circuit sends four gear position control signals corresponding to control the switching of the four input high-speed switching circuits and the output high-speed switching circuits. It realizes the automatic identification and switching function of input range, stable circuit operation, high conversion precision, strong anti-interference ability, and can realize high-precision, low-noise, wide-range current-voltage conversion.

Description

Adaptive wide-range current-voltage conversion device

technical field

The invention relates to the technical field of reading out the front end of a current output detector, in particular to an adaptive wide-range current-voltage conversion circuit.

Background technique

With the continuous development of accelerator technology, in order to meet the experimental needs of more nuclear physics and interdisciplinary subjects, the energy range of accelerator output is getting larger and larger, and the requirements for beam quality are getting higher and higher. Beam diagnosis is one of the key links in the accelerator system. Beam diagnosis detectors include a large number of weak current output detectors for beam profile monitoring, beam halo monitoring and emittance monitoring, such as strips for profile monitoring Ionization chambers and multi-wire proportional chambers, wire sweepers for beam halo and emittance measurements, etc. At present, the front-end electronics of current output detectors related to beam diagnosis systems usually use impedance conversion method or integral conversion method to convert the current into a voltage signal, and the voltage converted by the integral conversion method represents the total charge within a certain period of time, real-time Poor, so systems with higher timeliness requirements use impedance conversion method, called current-voltage conversion (IVC).

For weak current signals that are constantly changing, most of the traditional, fixed-range current-voltage conversion circuits have real-time processing capabilities of 2 to 3 orders of magnitude. Measuring range. The conventional processing method is to discard some smaller or larger signals, or artificially replace the electronic system with different ranges, which greatly reduces the precision and accuracy of the beam current diagnosis system, increases the beam adjustment time, and affects The utilization rate of the accelerator is reduced, and a lot of manpower, financial resources and time are wasted. At the same time, due to the need for staff to go to the site to replace the equipment, personnel safety accidents are extremely prone to occur. Therefore, the traditional, fixed-range current-voltage conversion circuit is difficult to meet the beam diagnosis requirements in high-precision experiments.

Contents of the invention

The purpose of the present invention is to provide an adaptive wide-range current-voltage conversion device to avoid the poor real-time performance of the existing wide-range current signal readout technology and the inability to meet the needs of high-precision experiments, thereby effectively solving the existing problems in the prior art.

In order to achieve the above object, the technical solution adopted by the present invention is: the self-adaptive wide-range current-voltage conversion device is characterized in that it includes four input high-speed switching circuits connected to the current signal I _in of the shield input respectively, and each input The high-speed switching circuit is connected in series with the current-voltage conversion circuit and the output high-speed switching circuit in parallel, and then connected with the inverting amplifier and the voltage follower. The voltage signal output by the inverting amplifier and the voltage follower is divided into three channels, and the inverting amplifier And one output of the voltage follower is the analog voltage output Vout, and the other two outputs of the inverting amplifier and the voltage follower are respectively connected to the control logic circuit through the high-speed low-threshold discrimination circuit and the high-speed high-threshold discrimination circuit. The current-voltage conversion circuit includes four Each gear interval, the switching action of each input high-speed switching circuit and the corresponding output high-speed switching circuit in the four-way input high-speed switching circuit is controlled by the control logic circuit.

Described four-way input high-speed switching circuit structure is identical, and each road input high-speed switching circuit in the four-way input high-speed switching circuit comprises a DMOS high-speed analog switch, two resistances and a fast inverter, and the input signal I _in is connected with the DMOS high-speed analog switch. The Source terminal of the switch is connected, the Body terminal of the DMOS high-speed analog switch is connected to -5V voltage, the input signal I _in enters from the Source terminal of the DMOS tube, the input signal I _in is output from the Drain terminal under the control of the Gate terminal, and the control signal Ctrl1 passes through the inversion After the device B1, it works together with the resistors R1 and R2 to control the Gate terminal of the DMOS high-speed analog switch. When Ctrl1 is at low level, the Source terminal of M1 is connected to the Drain terminal, and the I _in signal is output from the Drain terminal of M1. When Ctrl1 is at When the level is high, the Source terminal of M1 is disconnected from the Drain terminal, and only one of the four DMOS high-speed analog switches is turned on at the same time, and the control logic circuit outputs control signals Ctrl1, Ctrl2, Ctrl3 and Ctrl4 after passing through the inverter. Control the Gate terminals of the four DMOS transistors. At the same time, only one of the four DMOS high-speed analog switches is turned on, and the other three are turned off.

The current-voltage conversion circuit includes four gear intervals, and the four-way input high-speed switching circuits are respectively connected to the corresponding four-speed current-voltage conversion circuits, and the output ends of the four-speed current-voltage conversion circuits are respectively connected to the corresponding output high-speed switching circuits. The structure of the current-voltage conversion circuit for the four gears is the same, and the structure of the output high-speed switching circuit corresponding to the four-speed current-voltage conversion circuit is the same. At the same time, only one of the output high-speed switching circuits is controlled to be on, and the other three high-speed switching circuits are all controlled to be off. On, when the system is powered on and initialized, Ctrl4 output by the control logic circuit is at low level, and Ctrl1, Ctrl2, and Ctrl3 are at high level, and the control signals Ctrl1, Ctrl2, Ctrl3, and Ctrl4 output by the control logic circuit correspond to control the four-speed current voltage The on-off of the output terminal of the conversion circuit realizes the corresponding selection of the current and voltage conversion output and input; the voltage signal output by the output high-speed switching circuit is input to the inverting proportional operational amplifier circuit, and the voltage signal is appropriately amplified and inverted; the signal after inverting and amplifying Input to the voltage follower, the function of the voltage follower is to increase the output drive capability and isolate the front and rear circuits.

The output high-speed switching circuit corresponding to the fourth gear current-voltage conversion circuit has the same structure, and the output high-speed switching circuit corresponding to the first gear current-voltage conversion circuit consists of two DMOS high-speed switches M2, M3, two resistors R6, R7, and a small The base diode D1 and capacitor C1 are composed of a voltage signal input from the Source terminal of M3, the Body terminal of M3 is connected to -5V voltage, the Gate terminal of M3 is connected to the Drain terminal of M2 and a resistor R5 is connected in series, and the other terminal of R5 is connected to +5V voltage, the Gate terminal and Source terminal of M2 are connected to -5V voltage, the Source terminal of M2 and the Gate terminal are connected with resistor R7 and Schottky diode D1, and the Gate terminal of M2 is connected in series with a capacitor C1 and then connected to the control logic circuit Ctrl1 output terminal; when Ctrl1 is high level, M2 is turned on, the Gate terminal voltage of M3 is -5V, M3 is completely cut off, and the Source terminal voltage of M3 cannot be output from the Drain terminal; when Ctrl1 is low level, M2 is cut off, and M3 The Gate terminal voltage of M3 is +5V, M3 is turned on, and the Source terminal voltage of M3 is output from the Drain terminal.

Described inverting amplification and voltage follower comprises the inverting amplifier circuit that is made up of high-speed operational amplifier U1 and three resistors R25, R26, R27 and the voltage follower that is formed by high-speed operational amplifier U2, outputs the voltage of high-speed switching circuit output The signal is input to the inverting amplifier circuit, input from the inverting terminal of the operational amplifier U1, the signal is amplified twice, and the output voltage range is 0~5V (or 0~-5V); the inverting amplifier circuit is connected to a voltage follower, increasing output voltage drive capability.

The voltage signal output by the inverting amplification and the voltage follower is divided into three paths, one path is the analog voltage output Vout, which can directly perform analog-to-digital conversion; the other path is input to the high-speed voltage comparator U3 and the low-threshold reference voltage V _{REF_L} The low-threshold discrimination circuit composed of Vout is compared with the set low threshold voltage V _REF-L , and V _REF-L is set to 40mV (or -40mV). When the Vout voltage is less than the set threshold voltage V _REF-L , Then the high-speed voltage comparator U3 output signal _SL is high level, when the Vout voltage is greater than this threshold voltage, then the high-speed voltage comparator output signal _SL is low level; A high-threshold discrimination circuit composed of a high-threshold reference voltage V _{REF_H} , Vout is compared with the set high-threshold voltage V _REF-H , and V _REF-H is set to 4.8V (or -4.8V), when the Vout voltage is less than the set When the threshold voltage V _REF-H , the high-speed voltage comparator output signal S _H is low level, when the Vout voltage is greater than the threshold voltage V _REF-H , the high-speed voltage comparator output signal S _H is high level, the two A high-speed threshold discrimination circuit single discrimination time is less than 10nS.

The control logic circuit adopts a large-scale programmable logic device, the working voltage is +3.3V, the working clock frequency is 100MHz, the input signal includes the low threshold mark _SL , the high threshold mark _SH , and the output signal includes the gear position 1 The switching control signal Ctrl1, the gear position 2 switching control signal Ctrl2, the gear position 3 switching control signal Ctrl3, and the gear position 4 switching control signal Ctrl4.

In the four-speed current-voltage conversion circuit, the first-level current-voltage conversion circuit is composed of a low-noise high-precision operational amplifier A1 and a T-shaped resistor network composed of three resistors R3, R4 and R5. By adjusting the voltage of R3, R4 and R5 The size relationship makes the conversion gain of the first stage of current-voltage conversion 2.3×10 ⁹ , the current is input from the inverting terminal of the operational amplifier A1, the positive-phase terminal of the operational amplifier A1 is grounded, and the input current signal is fully converted on the T-shaped resistor network For voltage signal output, the first gear current-voltage conversion circuit converts the input current signal of 10pA to 1nA (or -10pA to -1nA) into a voltage signal output in real time; the second gear current-voltage conversion circuit consists of a low-noise high-precision operational amplifier A2 and three resistors R10, R11 and R12 are composed of a T-shaped resistor network. By adjusting the size relationship of R10, R11 and R12, the conversion gain of the second gear of current and voltage conversion is 2.3×10 ⁷ , and the second gear of current and voltage conversion The circuit converts the input current signal of 1nA to 100nA (-1nA to -100nA) into a voltage signal output in real time; the third gear current-voltage conversion circuit is composed of a low-noise and high-precision operational amplifier A3 and a resistor R17. By adjusting R17, the current and voltage The conversion gain of the third gear is 2.3×10 ⁵ , the third gear current-voltage conversion circuit converts the input current signal of 100nA～10uA (-100nA～-10uA) into a voltage signal output in real time; the fourth gear current-voltage conversion circuit It is composed of low-noise and high-precision operational amplifier A4 and resistor R22. By adjusting R22, the conversion gain of the fourth gear of current-voltage conversion is 2.3×10 ³ , and the input of the fourth gear current-voltage conversion circuit is 10uA～1mA (-10uA～- 1mA) current signal is converted into voltage signal output in real time; the voltage range converted by the four-speed current-voltage conversion circuit is 0-2.5V (or 0-2.5V), and only one of the current-voltage conversion circuits is working at the same time state, the input terminals and output terminals of the remaining three-speed current-voltage conversion circuits are disconnected, and the voltage signals converted from current and voltage are connected to the output high-speed switching circuits, and the four output high-speed switching circuits correspond to the four input high-speed switching circuits one by one.

By adopting the above-mentioned technical solution, the beneficial effect of the present invention is: the self-adaptive wide-range current-voltage conversion device can process real-time input ranging from 10pA to 1mA (or -10pA to -1mA) across 8 orders of magnitude and continuously changing The frequency of the current signal is not greater than 1kHz, including four gears, each gear can handle input signals of 2 orders of magnitude, and can automatically identify the gear range of the input signal, and the single identification and switching time is less than 100nS. The output voltage signal range is 0~4.8V (or 0~-4.8V). It has high sensitivity, large dynamic range and good linearity, thus providing fast, simple and reliable methods and means for wide-range weak and small current signal processing in accelerator beam diagnosis, nuclear physics, particle physics research and other related fields . It improves the system's ability to process signals in real time, and realizes the automatic identification and switching of input ranges. It has greater practicability and superiority in real-time acquisition systems for wide-range weak and small current signals in beam diagnostic systems and nuclear physics experiments.

Description of drawings

Fig. 1 is a circuit principle block diagram of the present invention;

Fig. 2 is a circuit diagram of the present invention;

Fig. 3 is a timing diagram of the present invention.

Detailed ways

The principles and features of the present invention are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the present invention, and are not intended to limit the scope of the present invention.

As shown in Figures 1 to 3, the adaptive wide-range current-voltage conversion device is characterized in that it includes four input high-speed switching circuits connected to the shielded input current signal I _in respectively, and each input high-speed switching circuit is sequentially connected with The current-voltage conversion circuit and the output high-speed switching circuit are connected in parallel after being connected in series, and then connected with the inverting amplifier and voltage follower. The output is the analog voltage output Vout, and the other two outputs of the inverting amplifier and the voltage follower are respectively connected to the control logic circuit through the high-speed low-threshold discrimination circuit and the high-speed high-threshold discrimination circuit. The current-voltage conversion circuit includes four gear intervals, The switching action between each input high-speed switching circuit and the corresponding output high-speed switching circuit in the four input high-speed switching circuits is controlled by the control logic circuit.

Described four-way input high-speed switching circuit structure is identical, and each road input high-speed switching circuit in the four-way input high-speed switching circuit comprises a DMOS high-speed analog switch, two resistances and a fast inverter, and the input signal I _in is connected with the DMOS high-speed analog switch. The Source terminal of the switch is connected, the Body terminal of the DMOS high-speed analog switch is connected to -5V voltage, the input signal I _in enters from the Source terminal of the DMOS tube, the input signal I _in is output from the Drain terminal under the control of the Gate terminal, and the control signal Ctrl1 passes through the inversion After the device B1, it works together with the resistors R1 and R2 to control the Gate terminal of the DMOS high-speed analog switch. When Ctrl1 is at low level, the Source terminal of M1 is connected to the Drain terminal, and the I _in signal is output from the Drain terminal of M1. When Ctrl1 is at When the level is high, the Source terminal of M1 is disconnected from the Drain terminal, and only one of the four DMOS high-speed analog switches is turned on at the same time, and the control logic circuit outputs control signals Ctrl1, Ctrl2, Ctrl3 and Ctrl4 after passing through the inverter. Control the Gate terminals of the four DMOS transistors. At the same time, only one of the four DMOS high-speed analog switches is turned on, and the other three are turned off.

The current-voltage conversion circuit includes four gear intervals, and the four-way input high-speed switching circuits are respectively connected to the corresponding four-speed current-voltage conversion circuits, and the output ends of the four-speed current-voltage conversion circuits are respectively connected to the corresponding output high-speed switching circuits. The structure of the current-voltage conversion circuit for the four gears is the same, and the structure of the output high-speed switching circuit corresponding to the four-speed current-voltage conversion circuit is the same. At the same time, only one of the output high-speed switching circuits is controlled to be on, and the other three high-speed switching circuits are all controlled to be off. On, when the system is powered on and initialized, Ctrl4 output by the control logic circuit is at low level, and Ctrl1, Ctrl2, and Ctrl3 are at high level, and the control signals Ctrl1, Ctrl2, Ctrl3, and Ctrl4 output by the control logic circuit correspond to control the four-speed current voltage The on-off of the output terminal of the conversion circuit realizes the corresponding selection of the current and voltage conversion output and input; the voltage signal output by the output high-speed switching circuit is input to the inverting proportional operational amplifier circuit, and the voltage signal is appropriately amplified and inverted; the signal after inverting and amplifying Input to the voltage follower, the function of the voltage follower is to increase the output drive capability and isolate the front and rear circuits.

The output high-speed switching circuit corresponding to the fourth gear current-voltage conversion circuit has the same structure, and the output high-speed switching circuit corresponding to the first gear current-voltage conversion circuit consists of two DMOS high-speed switches M2, M3, two resistors R6, R7, and a small The base diode D1 and capacitor C1 are composed of a voltage signal input from the Source terminal of M3, the Body terminal of M3 is connected to -5V voltage, the Gate terminal of M3 is connected to the Drain terminal of M2 and a resistor R5 is connected in series, and the other terminal of R5 is connected to +5V voltage, the Gate terminal and Source terminal of M2 are connected to -5V voltage, the Source terminal of M2 and the Gate terminal are connected with resistor R7 and Schottky diode D1, and the Gate terminal of M2 is connected in series with a capacitor C1 and then connected to the control logic circuit Ctrl1 output terminal; when Ctrl1 is high level, M2 is turned on, the Gate terminal voltage of M3 is -5V, M3 is completely cut off, and the Source terminal voltage of M3 cannot be output from the Drain terminal; when Ctrl1 is low level, M2 is cut off, and M3 The Gate terminal voltage of M3 is +5V, M3 is turned on, and the Source terminal voltage of M3 is output from the Drain terminal.

Described inverting amplification and voltage follower comprises the inverting amplifier circuit that is made up of high-speed operational amplifier U1 and three resistors R25, R26, R27 and the voltage follower that is formed by high-speed operational amplifier U2, outputs the voltage of high-speed switching circuit output The signal is input to the inverting amplifier circuit, input from the inverting terminal of the operational amplifier U1, the signal is amplified twice, and the output voltage range is 0~5V (or 0~-5V); the inverting amplifier circuit is connected to a voltage follower, increasing output voltage drive capability.

The voltage signal output by the inverting amplification and the voltage follower is divided into three paths, one path is the analog voltage output Vout, which can directly perform analog-to-digital conversion; the other path is input to the high-speed voltage comparator U3 and the low-threshold reference voltage V _{REF_L} The low-threshold discrimination circuit composed of Vout is compared with the set low threshold voltage V _REF-L , and V _REF-L is set to 40mV (or -40mV). When the Vout voltage is less than the set threshold voltage V _REF-L , Then the high-speed voltage comparator U3 output signal _SL is high level, when the Vout voltage is greater than this threshold voltage, then the high-speed voltage comparator output signal _SL is low level; A high-threshold discrimination circuit composed of a high-threshold reference voltage V _{REF_H} , Vout is compared with the set high-threshold voltage V _REF-H , and V _REF-H is set to 4.8V (or -4.8V), when the Vout voltage is less than the set When the threshold voltage V _REF-H , the high-speed voltage comparator output signal S _H is low level, when the Vout voltage is greater than the threshold voltage V _REF-H , the high-speed voltage comparator output signal S _H is high level, the two A high-speed threshold discrimination circuit single discrimination time is less than 10nS.

The control logic circuit adopts a large-scale programmable logic device, the working voltage is +3.3V, the working clock frequency is 100MHz, the input signal includes the low threshold mark _SL , the high threshold mark _SH , and the output signal includes the gear position 1 The switching control signal Ctrl1, the gear position 2 switching control signal Ctrl2, the gear position 3 switching control signal Ctrl3, and the gear position 4 switching control signal Ctrl4.

In the four-speed current-voltage conversion circuit, the first-level current-voltage conversion circuit is composed of a low-noise high-precision operational amplifier A1 and a T-shaped resistor network composed of three resistors R3, R4 and R5. By adjusting the voltage of R3, R4 and R5 The size relationship makes the conversion gain of the first stage of current-voltage conversion 2.3×10 ⁹ , the current is input from the inverting terminal of the operational amplifier A1, the positive-phase terminal of the operational amplifier A1 is grounded, and the input current signal is fully converted on the T-shaped resistor network For voltage signal output, the first gear current-voltage conversion circuit converts the input current signal of 10pA to 1nA (or -10pA to -1nA) into a voltage signal output in real time; the second gear current-voltage conversion circuit consists of a low-noise high-precision operational amplifier A2 and three resistors R10, R11 and R12 are composed of a T-shaped resistor network. By adjusting the size relationship of R10, R11 and R12, the conversion gain of the second gear of current and voltage conversion is 2.3×10 ⁷ , and the second gear of current and voltage conversion The circuit converts the input current signal of 1nA to 100nA (-1nA to -100nA) into a voltage signal output in real time; the third gear current-voltage conversion circuit is composed of a low-noise and high-precision operational amplifier A3 and a resistor R17. By adjusting R17, the current and voltage The conversion gain of the third gear is 2.3×10 ⁵ , the third gear current-voltage conversion circuit converts the input current signal of 100nA～10uA (-100nA～-10uA) into a voltage signal output in real time; the fourth gear current-voltage conversion circuit It is composed of low-noise and high-precision operational amplifier A4 and resistor R22. By adjusting R22, the conversion gain of the current-voltage conversion level 3 is 2.3×10 ³ , and the fourth-level current-voltage conversion circuit will input 10uA～1mA (-10uA～-1mA ) current signal is converted into a voltage signal output in real time; the voltage range converted by the four-speed current-voltage conversion circuit is 0-2.5V (or 0-2.5V), and only one of the current-voltage conversion circuits is working at the same time , the input terminals and output terminals of the remaining three-speed current-voltage conversion circuits are all disconnected, and the voltage signals converted from current and voltage are connected to the output high-speed switching circuits, and the four output high-speed switching circuits correspond to the four input high-speed switching circuits one by one.

The self-adaptive wide-range current-voltage conversion device can process current signals in real time with a continuously changing frequency not greater than 1kHz and an input range of 10pA to 1mA (or -10pA to -1mA) spanning 8 orders of magnitude; it includes four gears in total Each gear can handle input signals of two orders of magnitude, and can automatically identify the gear range of the input signal, and the single identification and switching time is less than 100nS; the output voltage signal range is 0~4.8V (or 0~-4.8V V); the circuit is installed in a sealed shielding box, and its integral nonlinear error is less than 0.9% after testing; the circuit works stably, with high conversion accuracy and strong anti-interference ability. It realizes adaptive wide-range current-voltage conversion, fast self-adaptive recognition and high-speed gear switching, has high sensitivity, large dynamic range and good linearity, and can continuously change the frequency not greater than 1kHz within 8 orders of magnitude The current signal is converted into a voltage signal that can be directly collected in real time, which improves the system's ability to process signals in real time, and provides a simple and effective new method for the readout of wide-range current output detector signals in beam diagnosis and nuclear physics experiment systems. method.

The working process of an adaptive wide-range current-voltage conversion circuit of the present invention: when the circuit is powered on and reset, Ctrl4 is set to low level, Ctrl1, Ctrl2 and Ctrl3 are high level, in order to reduce errors, the low level time of Ctrl4 It must be greater than 60nS, so it is set to 100nS in this circuit, and the control logic circuit reads the state of the S _L and S _H signals while waiting for 90nS (Ctrl4 is still in a low state). If S _L is high level and _SH is low level, the Ctrl3 output by the control logic circuit is low level, and Ctrl1, Ctrl2 and Ctrl4 are high level; if S _L is low level, _SH is high level level, or S _L is low level, _SH is low level, then the Ctrl1, Ctrl2, Ctrl3 and Ctrl4 output by the control logic circuit continue to maintain the original state. After Ctrl3 is at low level, set its high level time as 100nS, and the control logic circuit waits for 90nS to read the state of S _L and S _H signals. If S _L is high level and _SH is low level, the Ctrl2 output by the control logic circuit is low level, and Ctrl1, Ctrl3 and Ctrl4 are high level; if S _L is low level, _SH is high level level, then control logic circuit output Ctrl4 is low level, Ctrl1, Ctrl2 and Ctrl3 are high level; if S _L is low level, _SH is also low level, control logic circuit output Ctrl1, Ctrl2, Ctrl3 and Ctrl4 continue to maintain their original state. After Ctrl2 is at low level, set its high level time as 100nS, and the control logic circuit waits for 90nS to read the state of S _L and S _H signals. If S _L is high level and _SH is low level, the Ctrl1 output by the control logic circuit is low level, and Ctrl2, Ctrl3 and Ctrl4 are high level; if S _L is low level, _SH is high level level, the control logic circuit output Ctrl3 is low level, Ctrl1, Ctrl2 and Ctrl4 are high level; if S _L is low level, _SH is low level, then the control logic circuit output Ctrl1, Ctrl2, Ctrl3 and Ctrl4 continue to maintain the original state. After Ctrl1 is at high level, set its high level time as 100nS, and the control logic circuit waits for 90nS to read the state of S _L and S _H signals. If S _L is high level, _SH is low level, or S _L is low level, _SH is also low level, then the Ctrl1, Ctrl2, Ctrl3 and Ctrl4 output by the control logic circuit continue to maintain the original state; if S _L is low level, _SH is high level, then the Ctrl2 output by the control logic circuit is low level, and Ctrl1, Ctrl3 and Ctrl4 are high level.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (6)

1. An adaptive wide-range current-voltage conversion device is characterized in that it comprises four input high-speed switching circuits connected with the current signal I _in of the shielding input respectively, and each input high-speed switching circuit is connected with the current-voltage conversion circuit and the output high-speed switching circuit successively. The switching circuits are connected in parallel with each other after being connected in series, and then connected with the inverting amplifier and voltage follower. The voltage signal output by the inverting amplifier and voltage follower is divided into three channels, one is the analog voltage output Vout, and the other two channels pass through the high-speed low-threshold The discrimination circuit and the high-speed high-threshold discrimination circuit are connected to the control logic circuit. The current-voltage conversion circuit includes four gear ranges, and the switching action of each input high-speed switching circuit and the corresponding output high-speed switching circuit in the four gears is controlled. In the control logic circuit; the four-way input high-speed switching circuit has the same structure, and each input high-speed switching circuit in the four-way input high-speed switching circuit includes a DMOS high-speed analog switch, two resistors and an inverter, and the input signal I _in Connect with the Source terminal of the DMOS high-speed analog switch, the Body terminal of the DMOS high-speed analog switch is connected to -5V voltage, the input signal I _in enters from the Source terminal of the DMOS tube, the input signal I _in is output from the Drain terminal under the control of the Gate terminal, and the control signal After Ctrl1 passes through inverter B1, it works together with resistors R1 and R2 to control the Gate terminal of the DMOS high-speed analog switch. When Ctrl1 is low, the Source terminal of M1 is connected to the Drain terminal, and the I _in signal is output from the Drain terminal of M1. , when Ctrl1 is high level, the Source terminal of M1 is disconnected from the Drain terminal, and the control logic circuit outputs control signals Ctrl1, Ctrl2, Ctrl3 and Ctrl4 to control the Gate terminals of the four DMOS tubes correspondingly after passing through the inverter. Only one of the four DMOS high-speed analog switches is turned on, and the other three are disconnected; the four-way input high-speed switching circuit is respectively connected to the corresponding four-speed current-voltage conversion circuit, and the output terminals of the four-speed current-voltage conversion circuit are respectively connected to the corresponding The output high-speed switching circuit has the same structure as the four-speed current-voltage conversion circuit, and the output high-speed switching circuit corresponding to the four-speed current-voltage conversion circuit has the same structure. At the same time, only one of the output high-speed switching circuits is controlled to be turned on, and the other three high-speed switching circuits All the circuits are controlled to be disconnected. When the system is powered on and initialized, the control logic circuit output Ctrl4 is low level, Ctrl1, Ctrl2 and Ctrl3 are high level, and the control logic circuit output control signals Ctrl1, Ctrl2, Ctrl3 and Ctrl4 Correspondingly control the on-off of the output terminal of the four-speed current-voltage conversion circuit, and realize the corresponding selection of the current-voltage conversion output and input; output the voltage signal output by the high-speed switching circuit and input it to the inverting proportional operational amplifier circuit, and appropriately amplify and invert the voltage signal; The inverting and amplified signal is input to the voltage follower. The function of the voltage follower is to increase the output drive capability and isolate the front and rear circuits. 2. The adaptive wide-range current-voltage conversion device as claimed in claim 1, characterized in that: the output high-speed switching circuit corresponding to the first gear current-voltage conversion circuit of the four-speed current-voltage conversion circuit consists of two DMOS high-speed Switch M2, M3, two resistors R6, R7, a Schottky diode D1 and capacitor C1, where the voltage signal is input from the Source terminal of M3, the Body terminal of M3 is connected to -5V voltage, and the Gate terminal of M3 is connected to the M2 The Drain terminal is connected in series with a resistor R6, the other terminal of R6 is connected to +5V voltage, the Gate terminal and Source terminal of M2 are connected to -5V voltage, and the Source terminal of M2 is connected to Gate terminal resistor R7 and Schottky diode D1, M2 The Gate terminal is connected in series with a capacitor C1 and then connected to the Ctrl1 output terminal of the control logic circuit; when Ctrl1 is at a high level, M2 is turned on, the Gate terminal voltage of M3 is -5V, M3 is completely cut off, and the Source terminal voltage of M3 cannot be changed from Drain Terminal output; when Ctrl1 is low level, M2 is cut off, the Gate terminal voltage of M3 is +5V, M3 is turned on, and the Source terminal voltage of M3 is output from the Drain terminal. 3. The self-adaptive wide-range current-voltage conversion device as claimed in claim 1, characterized in that: said inverting amplifier and voltage follower comprises an inverter composed of a high-speed operational amplifier U1 and three resistors R25, R26, and R27. The phase amplifier circuit and the voltage follower composed of high-speed operational amplifier U2 output the voltage signal output by the high-speed switching circuit to the inverting amplifier circuit, input from the inverting terminal of the operational amplifier U1, and amplify the signal by two times, and the output voltage range It is 0 ~ 5V or 0 ~ -5V; the inverting amplifier circuit is connected to a voltage follower to increase the driving capability of the output voltage. 4. The self-adaptive wide-range current-voltage conversion device as claimed in claim 1, characterized in that: the voltage signal output by the inverting amplification and voltage follower is divided into three paths, one path is an analog voltage output Vout, which can be directly Perform analog-to-digital conversion; the other input is to the low-threshold discrimination circuit composed of high-speed voltage comparator U3 and low-threshold reference voltage V _REF-L , Vout is compared with the set low-threshold reference voltage V _REF-L , V _REF-L Set to 40mV or -40mV, when the Vout voltage is lower than the set low threshold reference voltage V _REF-L , the high-speed voltage comparator U3 output signal S _L is high level, when the Vout voltage is greater than the low threshold reference voltage V REF-L When _REF-L , the output signal S _L of the high-speed voltage comparator is low level; there is another input to the high-threshold discrimination circuit composed of the high-speed voltage comparator U4 and the high-threshold reference voltage V _REF-H , Vout and the setting Compared with the high-threshold reference voltage V _REF-H , V _REF-H is set to 4.8V or -4.8V, when the Vout voltage is less than the set high-threshold reference voltage V _REF-H , the high-speed voltage comparator output signal S _H is low level, when the Vout voltage is greater than the high-threshold reference voltage V _REF-H , the high-speed voltage comparator output signal S _H is high-level, and the single discrimination time of these two high-speed threshold discrimination circuits is less than 10nS. 5. The adaptive wide-range current-voltage conversion device as claimed in claim 1, characterized in that: the control logic circuit adopts a large-scale programmable logic device, the working voltage is +3.3V, the working clock frequency is 100MHz, and the input The signal includes the low-threshold mark S _L and the high-threshold mark _SH , and the output signal includes the switching control signal Ctrl1 of the gear position 1, the switching control signal Ctrl2 of the gear position 2, the switching control signal Ctrl3 of the gear position 3 and the switching control signal Ctrl4 of the gear position 4 . 6. The self-adaptive wide-range current-voltage conversion device as claimed in claim 1 or 2, characterized in that: the first gear current-voltage conversion circuit in the four-speed current-voltage conversion circuit is composed of low-noise high-precision operational amplifier A1 and The T-shaped resistor network composed of three resistors R3, R4 and R5 is composed. By adjusting the size relationship of R3, R4 and R5, the conversion gain of the first gear of current-voltage conversion is 2.3×10 ⁹ , and the current is from the inverting phase of the operational amplifier A1. The positive phase terminal of the operational amplifier A1 is grounded, and the input current signal is converted into a voltage signal output on the T-type resistor network. The first gear current-voltage conversion circuit will input a current of 10pA ~ 1nA or -10pA ~ -1nA The signal is converted into a voltage signal output in real time; the second gear current-voltage conversion circuit is composed of a low-noise high-precision operational amplifier A2 and a T-shaped resistor network composed of three resistors R10, R11 and R12. By adjusting the size relationship of R10, R11 and R12 The conversion gain of the second gear of current-voltage conversion is 2.3×10 ⁷ , the second gear current-voltage conversion circuit converts the input current signal of 1nA ~ 100nA or -1nA ~ -100nA into a voltage signal output in real time; the third gear current voltage The conversion circuit is composed of low-noise and high-precision operational amplifier A3 and resistor R17. By adjusting R17, the conversion gain of the third gear of current-voltage conversion is 2.3×10 ⁵ , and the input of the third gear current-voltage conversion circuit is 100nA ~ 10uA or -100nA ~ -10uA current signal is converted into voltage signal output in real time; the fourth gear current-voltage conversion circuit is composed of low-noise high-precision operational amplifier A4 and resistor R22. By adjusting R22, the conversion gain of the fourth gear of current-voltage conversion is 2.3×10 ^3. The fourth-level current-voltage conversion circuit converts the input current signal of 10uA ~ 1mA or -10uA ~ -1mA into a voltage signal output in real time; the voltage range converted by the fourth-level current-voltage conversion circuit is 0 ~ 2.5V or 0 ~ -2.5V, only one of the current-voltage conversion circuits is in working condition at the same time, the input and output terminals of the other three current-voltage conversion circuits are disconnected, and the voltage signal converted from the current and voltage is connected to the output high-speed switching circuit. The four output high-speed switching circuits correspond one-to-one to the four input high-speed switching circuits.