Resistance simulation device based on multiplication-type digital-to-analog converter

Abstract

The invention relates to a resistance simulation device based on a multiplying type digital-to-analog converter, which comprises a digital signal processor DSP, an isolator, a multiplying digital-to-analog converter, an inverter, a comparison unit, a PID unit, a limiting unit and a driving circuit, a power transistor, a sampling resistor, a differential amplifier, an amplifier, an attenuator, a follower, a digital ground, an analog ground and external test power supplies. The invention constructs a fast and high-resolution resistance value simulation system with a multiplicative digital-to-analog converter as the core, adopts a PID link to eliminate the error generated by the system, and increases the limiting circuit to prevent the power tube from entering a dead zone or an overload, thereby realizing an accurate resistance. The simulation has high resolution, wide range of analog resistance values, fast circuit response, stable circuit parameters, low price and high reliability. According to the invention, a fast and high-resolution resistance value simulation system is built by taking a multiplying digital-to-analog converter as a core, errors generated by the system are eliminated by adopting a PID link, the limiting circuit is added to prevent the power tube from entering a dead zone or an overload, the analog resistance value range is wide, the circuit reaction speed is fast, the circuit parameter is stable, the price is low, and the reliability is high.

Description

technical field [0001] The invention relates to a DC electronic load, in particular to a resistance simulation device based on a multiplying digital-to-analog converter. Background technique [0002] Traditional constant resistance simulation methods, such as figure 1 As shown, in the electronic load, the single-chip microcomputer usually controls the current loop or the voltage loop, changes the load current, thereby changes the output voltage and thus changes the resistance value, and realizes the constant resistance simulation. This kind of constant resistance simulation implemented by software requires analog-to-digital conversion of the analog voltage signal, and then the single-chip computer calculates the digital quantity and outputs the corresponding control quantity of the digital-to-analog converter to drive the power tube. Finally, it is realized by the successive approximation algorithm. This process takes a long time, resulting in slow response, low reliability...

AI Technical Summary

Problems solved by technology

The circuit can quickly realize constant resistance simulation through hardware, but due to the use of digital potentiometers, the number of digits is limited, resulting in low resolution of the resistance that can be simulated; high-end digital potentiometers are expensive and the number of digits generally does not exceed 16, making The applicability of the scheme is poor; there are no measures to eliminate system errors, and there are no restrictions on the amplitude of the drive circuit, which will easily lead to overload of the power tube, cause circuit oscillation, and cause system instability

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