WO2022062191A1

WO2022062191A1 - Parallel-connected highspeed low-voltage large-current pulsed constant current source

Info

Publication number: WO2022062191A1
Application number: PCT/CN2020/134880
Authority: WO
Inventors: 唐德平; 张建一; 桂芬; 朱国军
Original assignee: 合肥科威尔电源系统股份有限公司
Priority date: 2020-09-23
Filing date: 2020-12-09
Publication date: 2022-03-31
Also published as: CN112000167B; CN112000167A

Abstract

A parallel-connected highspeed low-voltage large-current pulsed constant current source, relating to the technical field of power sources. Multiple outputs are controlled separately, and a DSP controller (S14) sends an SPI signal, uniformly issues a same given pulse signal, and inputs same to a pulse signal generating source circuit (S13), thereby ensuring current sharing of the constant current source; a plurality of Hall current sensors of a main circuit (S11) respectively sample emitter output currents of a plurality of IGBTs as a feedback signal to be input to a pulsed constant current source control circuit (S12) for comparison with the given signal, so as to control a driving voltage, such that the plurality of IGBTs in the main circuit (S11) all operate in a linear region, and then the magnitude and the pulse width of the output current are controlled, thereby achieving constant current output; a control signal EN uniformly controls on and off of the pulse signal by means of a same I/O port, thereby ensuring timing consistency in control signal rising edge, achieving parallel connection of the plurality of IGBTs, and achieving the kilo-ampere level output current.

Description

A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source

technical field

The invention relates to the technical field of power supply, in particular to a multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source.

Background technique

Constant current source refers to a constant current source whose output current does not change with its own resistance and external voltage fluctuations. Pulsed constant current sources are used in semiconductor testing, laser diodes, superconductors and other tests. At present, the pulsed constant current sources commonly found in the market are not high in current, and the pulse rise time is relatively slow. With the development and progress of science and technology, there are many models in the field similar to semiconductors, and the current is as high as several thousand A. The constant current source puts forward very high requirements, so the research on a new type of multi-parallel, ultra-high-speed, pulsed, high-current constant current source is of high cutting-edge and importance.

An ideal constant current source should have the following characteristics: it does not change due to changes in load (output voltage); it does not change due to changes in ambient temperature; the internal resistance is infinite (so that its current can all flow out to the outside). A circuit that can provide a constant current is a constant current source circuit, also known as a current mirror circuit.

The basic constant current source circuit is mainly composed of an input stage and an output stage. The input stage provides a reference current, and the output stage outputs the required constant current. The basic principle of forming a constant current source circuit: the constant current source circuit is to be able to provide a stable current to ensure the stable operation of other circuits. That is, the constant current source circuit is required to output a constant current, so the device used as the output stage should have a volt-ampere characteristic with a saturated output current. This can be accomplished with a BJT or MOSFET operating in saturation with the output current.

In order to ensure that the current of the output transistor is stable, two conditions must be met: a) its input voltage must be stable—the input stage needs to be a constant voltage source; b) the output resistance of the output transistor is as large as possible (preferably infinite)— The output stage needs to be a constant current source.

Requirements for input stage devices: Because the input stage needs to be a constant voltage source, a device with voltage saturation volt-ampere characteristics can be used as the input stage. General pn junction diodes have this characteristic - exponentially rising volt-ampere characteristics; in addition, the diode formed by short-circuiting the source-drain of the enhancement mode MOSFET also has similar volt-ampere characteristics - parabolic rise volt-ampere characteristics. When a diode is used as an input stage device in an IC, it is generally an integrated diode that is properly connected by a triode, because this diode can not only adapt to the IC process, but also has its special advantages. For these triodes, it is required to have a certain amplification performance, so that the corresponding diodes have better constant voltage performance.

Requirements for output stage devices: If BJT is used, in order to increase its output resistance, it is necessary to try to reduce the Evarly effect (base width modulation effect), that is, to increase the Early voltage as much as possible. If MOSFET is used, in order to increase its output resistance, it is necessary to try to reduce its channel length modulation effect and offset effect. Therefore, long-channel MOSFETs are generally selected here instead of short-channel devices.

In the prior art, the application number 201610908411.X was published on February 22, 2017 in the Chinese invention patent application "Ultra-high-speed high-current pulsed constant current source" by connecting a large capacitor in parallel with the power supply, so that the initial stage of the load operation is mainly composed of capacitors. The stored energy provides a microsecond-level rising edge to the load; at the same time, a high-power Darlington tube is connected in series with the load to ensure that the load can pass a pulsed current of several hundred amperes, and it can also protect the load from working in a safe current mode. .

Although, the above-mentioned patent application can generate constant current pulses with corresponding pulse width and amplitude according to different needs, which can be applied to loads such as resistors and LEDs. The structure is simple, the function is stable, safe and reliable, and the rising edge is faster (tens of microseconds). , larger current (hundreds of amps), etc., but its output current only reaches 100 amps, and in the published literature of constant current sources, there is no multi-channel parallel, current amplitude reaches 1000 amps, rising A pulsed constant current source with a time of microseconds.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is how to design a high-speed high-current pulsed constant current source that can be connected in parallel with multiple channels, the output current can reach the kiloampere level, and the pulse rising speed is in the microsecond level.

The present invention solves the above-mentioned technical problems through the following technical solutions:

A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source, comprising a main circuit (S11), a pulse constant current source control circuit (S12), a pulse signal generating source (S13) circuit, and a DSP controller (S14); The main circuit (S11) includes a DC power supply DC5, a capacitor C, a plurality of IGBTs, a plurality of Hall current sensors and a load; the plurality of IGBTs are connected in parallel, and the emitters of the plurality of IGBTs are respectively connected to the positive pole and the collector of the DC power supply DC5. The electrodes are respectively connected to one end of the load, and the other end of the load is connected to the negative pole of the DC power supply DC5; the DSP controller (S14) sends out the SPI signal and the control signal EN and is input to the pulse signal generating source (S13) circuit; The pulse signal generating source (S13) circuit is connected to the pulse constant current source control circuit (S12), and is used to send multiple independent PWM signal sources with adjustable amplitude, pulse width and frequency to the pulse constant current source control circuit (S12). As a given signal; the multiple independent outputs of the pulse constant current source control circuit (S12) are respectively connected with the gates of multiple IGBTs of the main circuit (S11); the multiple Hall current sensors of the main circuit (S11) are respectively connected Sampling the emitter output currents of multiple IGBTs as feedback signals and input them to the pulse constant current source control circuit (S12) for comparison with a given signal to control the driving voltage, so that multiple IGBTs in the main circuit (S11) work at In the linear region, the output current and pulse width are controlled to achieve constant current output.

The difficulty of using multi-channel paralleling to achieve the constant current output of the thousand-amp level is how to achieve current sharing. The rising edge time of the control signal is microseconds, so it is difficult to ensure the consistency of the rising edge of the control signal and the accuracy of the current size control of each channel. The technical scheme of the present invention is independently controlled by multiple outputs, and the SPI signal is sent out by the DSP controller (S14), the same given voltage signal is issued uniformly, and is input to the pulse signal generating source (S13) circuit to ensure the constant current source current. The current sharing; the multiple Hall current sensors of the main circuit (S11) respectively sample the emitter output currents of multiple IGBTs as feedback signals and input them to the pulse constant current source control circuit (S12) for comparison with a given signal for control. The driving voltage makes multiple IGBTs in the main circuit (S11) work in the linear region, and controls the output current and pulse width to achieve constant current output; the control signal EN controls the opening of the pulse signal through the same I/O port. And turn off, ensure the consistency of the rising edge of the control signal, realize the parallel connection of multiple IGBTs, and the output current reaches the kiloamp level.

As a further improvement of the technical solution of the present invention, the pulse constant current source control circuit (S12) includes a multi-channel IGBT driving circuit with the same structure, and the output ends of the multi-channel IGBT driving circuit respectively correspond to the output terminals of the plurality of IGBTs. gate connection.

As a further improvement of the technical solution of the present invention, the IGBT driving circuit includes an operational amplifier, a DC power supply, a PNP-type triode, an NPN-type triode, and a driving resistor; the DC power supply supplies power to the operational amplifier, which is composed of Proportional-integral regulator, NPN type triode and NPN type triode constitute a push-pull drive circuit, the collector of NPN type triode and the emitter of NPN type triode are respectively connected between the positive and negative poles of the DC power supply, the push-pull drive circuit The input end of the IGBT is connected to the output end of the proportional-integral regulator, the output end of the push-pull drive circuit is connected to one end of the drive resistor, and the other end of the drive resistor serves as the output port of the IGBT drive circuit and is connected to the gate of the corresponding IGBT.

As a further improvement of the technical solution of the present invention, the pulse signal generating source (S13) circuit includes multiple independent PWM signal source circuits with the same structure, and the output ends of the multiple independent PWM signal source circuits output amplitude, pulse width and The frequency-adjustable multi-channel PWM signal source is respectively input to one input terminal of the proportional-integral regulator in the corresponding multi-channel IGBT drive circuit as a given signal; the other input terminal of the proportional-integral regulator is respectively connected with the main circuit. The output terminals of the plurality of Hall current sensors are connected to input the sampling current of the Hall current sensor as a feedback signal.

As a further improvement of the technical solution of the present invention, each of the independent PWM signal source circuits includes a digital isolation conversion chip, a digital-to-analog conversion chip, and a high-speed optocoupler. The SPI signal is isolated and transformed by the digital isolation conversion chip and then input to the In the digital-to-analog conversion chip, the digital-to-analog conversion chip is converted into an analog voltage with a controllable amplitude; the control signal EN generates an isolated enable signal through the high-speed optocoupler isolation to control the on-off of the digital-to-analog conversion chip and realize the control of the PWM signal. pulse width and frequency.

As a further improvement of the technical solution of the present invention, the capacitor C includes a plurality of Capson 63V/22000uF electrolytic capacitors and a plurality of EACO700V/845uF film capacitors, and the plurality of electrolytic capacitors are connected in parallel with the plurality of film capacitors.

As a further improvement of the technical solution of the present invention, the model of the plurality of IGBTs is Infineon FF600R12ME4.

As a further improvement of the technical solution of the present invention, the model of the plurality of Hall current sensors is Lyme sensor LF-505S.

As a further improvement of the technical solution of the present invention, the model of the operational amplifier is ADA4610-1, the model of the PNP transistor is FTZ951, and the model of the NPN transistor is FZT851.

As a further improvement of the technical solution of the present invention, the model of the digital isolation conversion chip is ADUM1401, the model of the digital-to-analog conversion chip is DAC8830, and the model of the high-speed optocoupler is 6N137.

The advantages of the present invention are:

(1) The technical scheme of the present invention is independently controlled by multiple outputs, and the DSP controller (S14) sends out the SPI signal, and sends the same given voltage signal uniformly, which is input to the pulse signal generating source (S13) circuit to ensure constant current. Source current sharing; multiple Hall current sensors of the main circuit (S11) respectively sample the emitter output currents of multiple IGBTs as feedback signals and input them to the pulse constant current source control circuit (S12) for comparison with a given signal, using To control the driving voltage, make multiple IGBTs in the main circuit (S11) work in the linear region, and control the output current size and pulse width to achieve constant current output; the control signal EN controls the pulse signal uniformly through the same I/O port The turn-on and turn-off of the control signal ensures the consistency of the rising edge of the control signal, realizes the parallel connection of multiple IGBTs, and the output current reaches the kiloamp level.

(2) The operational amplifier constitutes a proportional-integral regulator, whose adjustment speed can reach 21V/us, and has the characteristics of fast adjustment speed, low offset voltage and low temperature drift;

(3) NPN transistors and NPN transistors constitute a push-pull drive circuit, which enhances the drive capability; the output of the push-pull drive circuit is connected to the drive resistor, which improves the rising speed of the drive voltage.

(4) Multiple large electrolytic capacitors on the laminated busbar are discharged in parallel, reducing the parasitic inductance on the line, realizing the rise of microsecond level, and realizing the low ESR and low inductance of the main circuit of the circuit.

(5) The current sampling of the Hall current sensor adopts high-side isolation sampling to reduce the interference of sampling, and it is easy to achieve control accuracy.

(6) Using DSP instead of FPGA to implement, the cost is lower, and the scheme is more concise and easy to implement.

Description of drawings

FIG. 1 is a circuit schematic diagram of a multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to an embodiment of the present invention.

detailed description

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The technical solutions of the present invention are further described below in conjunction with the accompanying drawings and specific embodiments:

Example 1

As shown in Figure 1, a multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source includes a main circuit (S11), a pulse constant current source control circuit (S12), and a pulse signal generating source (S13) circuit; The pulse signal generating source (S13) circuit is connected with the pulse constant current source control circuit (S12), and is used to send the PWM signal source with adjustable amplitude, pulse width and frequency to the pulse constant current source control circuit (S12), as Given signal; the multiple outputs of the pulse constant current source control circuit (S12) are respectively connected to the multiple IGBTs of the main circuit (S11), and the emitter output currents of the multiple IGBTs of the main circuit (S11) are input to the feedback signal as a feedback signal. The pulse constant current source control circuit (S12) compares the given signal with the feedback signal, and uses a proportional-integral regulator to control the driving voltage, so that multiple IGBTs in the main circuit (S11) work in the linear region, so as to realize the control of the output current. And pulse width control to achieve constant current output.

The main circuit (S11) includes a DC power supply DC5, a capacitor C, and a plurality of IGBTs. In this embodiment, four IGBTs are used in parallel, which are respectively the first IGBT to the fourth IGBT, and a plurality of Hall current sensors, which are respectively the first IGBT and the fourth IGBT. A Hall current sensor to a fourth Hall current sensor and a load; both ends of the capacitor C are connected in parallel between the positive and negative poles of the DC power supply DC5; the emitter of the first IGBT, the emitter of the second IGBT, the emitter of the third IGBT The emitter and the emitter of the fourth IGBT are connected to the positive pole of the DC power supply DC5, and the collector of the first IGBT, the collector of the second IGBT, the collector of the third IGBT and the collector of the fourth IGBT are all connected to the load. One end, the other end of the load is connected to the negative electrode of the DC power supply DC5; the first Hall current sensor to the fourth Hall current sensor are respectively used to sample the emitter output currents of the first IGBT to the fourth IGBT, and feed them back to the pulse The constant current source control circuit (S12), through the control of the driving voltage in the pulse constant current source control circuit (S12), makes multiple IGBTs in the main circuit (S11) work in the linear region, and realizes the output current size and pulse width. The high-side isolation sampling reduces the interference of sampling, and it is easy to achieve control accuracy.

The DC power supply DC5 charges the capacitor C. The DC power supply DC5 is a 48V voltage power supply. The capacitor C is composed of multiple Capson 63V/22000uF electrolytic capacitors and multiple EACO 700V/845uF film capacitors in parallel. Multiple large electrolytic capacitors are discharged in parallel to reduce the parasitic inductance on the line, achieve a rise in microseconds, and achieve low ESR (Equivalent Series Resistance, equivalent series resistance of capacitors) and low inductance of the main circuit of the circuit.

The first IGBT to the fourth IGBT use Infineon FF600R12ME4, which makes the output current of each channel larger, so that the output current reaches the kiloamp level, and it is beneficial to control the rising edge time of each channel to reduce the current when the current is turned on. Overshoot; the first Hall current sensor to the fourth Hall current sensor use Lyme sensor LF-505S; the load is power semiconductor or resistance.

The pulse constant current source control circuit (S12) includes four-way IGBT drive circuits with the same structure, and the output ends of the four-way IGBT drive circuits are respectively connected to the gate of the first IGBT, the gate of the second IGBT, and the gate of the third IGBT. The gate and the gate of the fourth IGBT are connected.

Take the first IGBT drive circuit as an example to illustrate: the first IGBT drive circuit includes an operational amplifier U1 whose model is ADA4610-1; a DC power supply DC1 whose voltage is ±15V; a PNP transistor Q1 and a NPN transistor Q2, the model of the transistor Q1 is FTZ951, the model of the transistor Q2 is FZT851; a driving resistor R1; the DC power supply DC1 supplies power for the operational amplifier U1, and the operational amplifier U1 constitutes a proportional integral regulator, and its adjustment speed can reach 21V/us, has the characteristics of fast adjustment speed, low offset voltage and low temperature drift; transistor Q1 and transistor Q2 constitute a push-pull drive circuit, the collector of transistor Q2 and the emitter of transistor Q1 are respectively connected to the positive and negative poles of the DC power supply DC1 In between, the input end of the push-pull drive circuit is connected to the output end of the proportional-integral regulator, the output end of the push-pull drive circuit is connected to one end of the drive resistor R1, and the other end of the drive resistor R1 is used as the first IGBT drive The output port of the circuit is correspondingly connected to the gate of the first IGBT; the push-pull driving circuit enhances the driving capability; the driving resistor R1 improves the stability of the driving voltage.

The pulse signal generating source (S13) circuit includes four independent PWM signal source circuits with the same structure. The output ends of the four independent PWM signal source circuits output four PWM signal sources with adjustable amplitude, pulse width and frequency respectively, which are: PWM1 to PWM4; PWM1 to PWM4 are respectively input to one input of the proportional-integral regulator in the corresponding four-way IGBT drive circuit as a given signal; the other input of the proportional-integral regulator is respectively connected with the first input of the main circuit. The Hall current sensor is connected to the output end of the fourth Hall current sensor, and is used for inputting the sampling current of the Hall current sensor as a feedback signal.

Take the first independent PWM signal source circuit as an example to illustrate: the first independent PWM signal source circuit includes a digital isolation conversion chip U5, whose model is ADUM1401; a digital-to-analog conversion chip U9, whose model is DAC8830; High-speed optocoupler U13, its model is 6N137; DSP (Digital Signal Process, digital signal processing) controller (S14) sends out SPI signal and control signal EN; SPI (Serial Peripheral Interface, serial peripheral interface, a synchronous serial The interface technology is a high-speed, full-duplex, synchronous communication bus) signals including CS/SDI/SDO/CLK signals, SPI signals are isolated and transformed by the digital isolation conversion chip U5 and then input to the digital-to-analog conversion chip U9. The digital-to-analog conversion chip U9 is converted into an analog voltage with a controllable amplitude; the control signal EN is isolated by the high-speed optocoupler U13 to generate an isolated enable signal to control the on-off of the digital-to-analog conversion chip U9 to control the pulse width of the PWM signal and Frequency; using DSP instead of FPGA to achieve, the cost is lower, the solution is more concise and easy to implement.

The difficulty of using multi-channel paralleling to achieve the constant current output of the thousand-amp level is how to achieve current sharing. The rising edge time of the control signal is microseconds, so it is difficult to ensure the consistency of the rising edge of the control signal and the accuracy of the current size control of each channel. ; This technical scheme is controlled by multiple outputs independently, and the same given voltage signal is issued uniformly by the DSP to ensure the current sharing of the constant current source current; the opening and closing of the pulse signal are controlled uniformly through the same I/O port to ensure the control Consistency of the rising edge of the signal.

The above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The recorded technical solutions are modified, or some technical features thereof are equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source is characterized in that it includes a main circuit (S11), a pulse constant current source control circuit (S12), a pulse signal generating source (S13) circuit, and a DSP controller. (S14); the main circuit (S11) includes a DC power supply DC5, a capacitor C, a plurality of IGBTs, a plurality of Hall current sensors and a load; a plurality of IGBTs are connected in parallel, and the emitters of the plurality of IGBTs are respectively connected to the DC power supply DC5 The positive electrode and the collector of the load are respectively connected to one end of the load, and the other end of the load is connected to the negative electrode of the DC power supply DC5; the DSP controller (S14) sends out the SPI signal and the control signal EN and inputs it to the pulse signal generating source (S13) circuit ; The pulse signal generating source (S13) circuit is connected with the pulse constant current source control circuit (S12), and is used to send multiple independent adjustable amplitudes, pulse widths and frequencies to the pulse constant current source control circuit (S12). The PWM signal source is used as a given signal; the multiple independent outputs of the pulse constant current source control circuit (S12) are respectively connected with the gates of multiple IGBTs in the main circuit (S11); The current sensor samples the emitter output currents of multiple IGBTs as feedback signals and inputs them to the pulse constant current source control circuit (S12) for comparison with the given signal, which is used to control the driving voltage, so that the multiple IGBTs in the main circuit (S11) IGBTs all work in the linear region, and control the output current and pulse width to achieve constant current output.
A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 1, characterized in that, the pulse constant current source control circuit (S12) comprises a multi-channel IGBT drive circuit with the same structure, The output ends of the multi-channel IGBT driving circuit are respectively connected to the gate electrodes of the plurality of IGBTs correspondingly.
A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 2, wherein the IGBT drive circuit comprises an operational amplifier, a DC power supply, a PNP-type triode and an NPN-type A triode, a driving resistor; the DC power supply powers the operational amplifier, the operational amplifier constitutes a proportional-integral regulator, the NPN triode and the NPN triode constitute a push-pull drive circuit, the collector of the NPN triode, the emitter of the NPN triode They are respectively connected between the positive and negative poles of the DC power supply, the input end of the push-pull drive circuit is connected to the output end of the proportional-integral regulator, the output end of the push-pull drive circuit is connected to one end of the drive resistor, and the other end of the drive resistor is connected. One end is connected to the gate of the corresponding IGBT as an output port of the IGBT drive circuit.
A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 3, wherein the pulse signal generating source (S13) circuit comprises a multi-channel independent PWM signal source circuit with the same structure , the output terminals of the multi-channel independent PWM signal source circuit output the multi-channel PWM signal sources with adjustable amplitude, pulse width and frequency respectively, which are respectively input to one input terminal of the proportional-integral regulator in the corresponding multi-channel IGBT drive circuit, As a given signal; the other input end of the proportional-integral regulator is respectively connected with the output ends of a plurality of Hall current sensors of the main circuit, and is used to input the sampling current of the Hall current sensor as a feedback signal.
The multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 4, wherein each of the independent PWM signal source circuits comprises a digital isolation conversion chip, a digital-to-analog conversion chip , one is a high-speed optocoupler, the SPI signal is isolated and converted by the digital isolation conversion chip and then input to the digital-to-analog conversion chip, and converted into an analog voltage with a controllable amplitude through the digital-to-analog conversion chip; the control signal EN is isolated by the high-speed optocoupler isolation. The enable signal is used to control the on-off of the digital-to-analog conversion chip, so as to control the pulse width and frequency of the PWM signal.
A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 1, wherein the capacitor C comprises a plurality of Capson 63V/22000uF electrolytic capacitors and a plurality of EACO700V/845uF The film capacitors, the plurality of electrolytic capacitors are connected in parallel with the plurality of film capacitors.
A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 1, wherein the model of the plurality of IGBTs is Infineon FF600R12ME4.
The multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 1, wherein the model of the plurality of Hall current sensors is Lyme sensor LF-505S.
A multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 3, wherein the model of the operational amplifier is ADA4610-1, and the model of the PNP type triode is FTZ951, NPN type The model of the triode is FZT851.
The multi-channel parallel ultra-high-speed low-voltage high-current pulsed constant current source according to claim 5, wherein the model of the digital isolation conversion chip is ADUM1401, the model of the digital-to-analog conversion chip is DAC8830, the high-speed The optocoupler model is 6N137.