Square wave generating circuit

Abstract

The invention discloses a square wave generating circuit comprising a high-voltage direct current source, a tank circuit, a semiconductor switch, a charge resistor and a pulse output end used for loading tested equipment under test. Resistance value of the charge resistor can be reasonably selected by connecting the charge resistor in parallel on the pulse output end, so that charging time of semiconductor switch junction capacity can be greatly shortened, and a steep square-wave pulse of a falling edge can be realized; and meanwhile, a high-energy square-wave pulse with adjustable pulse width and level amplitude can be outputted by controlling closing time of the semiconductor switch, wide-range pulse adjustment from nanosecond level to millisecond level can be realized, and square wave generating circuit has the advantages of wide pulse adjustable range, level amplitude, convenience in control, reliable circuit and the like.

Description

【Technical field】 [0001] The invention belongs to the field of electromagnetic compatibility (EMC) measurement, and in particular relates to a square wave generating circuit. 【Background technique】 [0002] The anti-pulse capability of electronic equipment is an important indicator for evaluating its performance. Pulse voltage is a typical surge pulse. The evaluation of this indicator is usually to use a square wave generator to generate high-voltage pulses, which are loaded on the equipment under test (EUT). Both ends to check whether the device under test can work normally. [0003] The existing high-voltage square wave generating circuit such as figure 1 As shown, it includes a high-voltage DC source, an RC energy storage circuit, a semiconductor switch S1, and a pulse output terminal. In order to generate high-energy square wave pulses, it is required that the switch can withstand instantaneous high voltage of thousands of volts and high current of hundreds of amperes,...

AI Technical Summary

Problems solved by technology

[0004] Generally speaking, the junction capacitance of a semiconductor switch is nF level, and the equivalent resistance R of the device under test L It may be very large, and the charging time of the junction capacitance is very long, which causes the falling edge of the square wave to fall slowly, so that only pulses with a large pulse width can be output

For example, if the equivalent resistance R of the EUT L If it is greater than 10kΩ, the falling edge of the square wave will be at least greater than 10μs, and the device under test cannot obtain a 1μs or faster square wave, and the output pulse width is very large, and the amplitude is not flat, such as figure 2 As shown, it cannot meet the requirements of some electronic equipment that need to be tested with a narrow square wave with a steep edge

[0005] Therefore, the existing technical solutions generally can only realize high-energy wide square wave pulses, and the realized amplitude is not flat; even if there are some technical solutions that can realize narrow square waves, such as the patent publication No. A high-voltage square-wave pulse generator and a method for generating high-voltage square-wave pulses", not only the implementation method and device structure are complicated, but also the cost is high, and high-energy square-wave pulses cannot be realized, and the adjustable range of square-wave width is narrow

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