V. B. Voronkov

Dynistors with nanosecond response times

The results of studies of deep-level dynistors (DLDs) in modes of switching high-power nanosecond current pulses at a current rise rate of up to 200 A/ns unique for semiconductor switches are presented. The dependences of the switching energy loss in DLDs on the amplitude of the control current and the shape of triggering voltage pulses are shown. The electrophysical processes developing at the edge surface of a DLD subjected to the application of high-voltage triggering pulses are analyzed.

A high-power semiconductor switch of high-voltage pulses with a rise time of nanosecond duration

The results of studies of new fast-acting semiconductor devices—deep-level dynistors intended for use in high-power devices of nano-and microsecond pulsed-power technology—are presented. The possibility of switching multikiloampere current pulses having a rise rate of 200 kA/μs with the use of a single device with a 12-mm-diameter structure is shown. A high-power switch based on an assembly of dynistors with an operating voltage of 12 kV connected in series is described. The switch is capable of switching current pulses with a 1200-A amplitude and a 4-ns rise time.

High power semiconductor-based nano and subnanosecond, pulse generator with a low delay time

One of the promising designs of high-power nanosecond and subnanosecond pulse generators is based on the fast ionization dynistor (FID) stack triggered with nanosecond pulse of overvoltage. This pulse is usually formed by semiconductor opening switches. Delay time of these switches equals the sum of forward and reverse current pulse duration, i.e., several hundreds of nanoseconds. The novel opening switch, inverse recovery diode (IRD), is capable of forming a nanosecond pulse of voltage with the delay time equal to the reverse current pulse duration (15-20 ns) due to the special diode structure. High-voltage nanosecond pulse formed with IRD is used for fast triggering of the first FID from high-voltage dc-biased FID stack. The resulting fast overvoltage pulse is applied to the second FID, etc. As a result, the high-voltage FID-stack is switched for units of nanosecond. Total delay time of IRD-FID-based pulse generators is less than 30 ns.

Reverse switch-on dynistor switches of gigawatt-power microsecond pulses

A high-power (150 kA and 16 kV) small switch based on an assembly of reverse switch-on dynistors (RSDs) connected in series and a coaxial saturable-core choke, which creates conditions for their efficient switching, is described. An essential feature of this switch is a drastic reduction of the duration of the control action, as a result of which minimum dimensions and a low inductance of the saturable-core choke are ensured at a high (25 kA/μs) rise rate of the switched current. Increases in the control-current amplitude and rise rate that are required for maintaining the triggering charge at a constant level are attained thanks to the use of a fast-acting switch based on new semiconductor devices—deep-level dynistors—in the RSD-control circuit.

Semiconductor switches of laser pumping pulses of nanosecond duration

Switches of megawatt nanosecond pulses based on high-voltage (12 kV) assemblies of drift step-recovery diodes (DSRDs) and deep-level dynistors (DLDs) are described. Circuit diagrams allowing their use in laser technology are considered. Results of testing of the diode and dynistor switches in power supply circuits of nitrogen lasers at a frequency of 100 Hz are presented. Their high efficiency in shaping of pumping current pulses with a rise time of 10 ns and amplitudes of 500 A (a DSRD switch) and 900 A (a DLD switch) is shown.

A generator of high-voltage nanosecond pulses with a subnanosecond rise time

A generator of high-voltage pulses of nanosecond duration with a subnanosecond rise time is described. The generator contains a nanosecond-pulse shaper based on an assembly of drift step-recovery diodes (DSRDs) connected in series and a sharpening switch based on an assembly of deep-level dynistors (DLDs) connected in series. The results of tests of this generator at a pulse repetition rate of 100 Hz are presented. Voltage pulses with an amplitude of 20 kV, a rise time of 0.3 ns, and a duration of 10 ns are formed across a load with a resistance of 50 Ω.

Semiconductor formers of high-voltage pulses of nanosecond duration

A small former of high-voltage pulses of nanosecond duration based on new semiconductor devices—deep-level dynistors (DLDs)—is described. The former has been developed on the basis of the Marx voltage-multiplication principle and allows formation of 8-kV voltage pulses across an 8-Ω load at a 2.5-kV input-voltage level. A DLD-based former with an output diode opening switch based on assemblies of drift step-recovery diodes connected in series is described. The results of its being tested are presented. Voltage pulses with an amplitude of 25 kV and a rise time of 1 ns are obtained across a 100-Ω load.

Studying dynistor switches with nanosecond switching times

The results of studying the process of switching deep-level dynistors (DLDs) with 16- and 24-mm-diameter structures in the modes of switching micro- and nanosecond pulses with amplitudes of several kiloamperes are presented. It is shown that the dynistor switching process is highly uniform. The results of DLD tests at a high repetition rate of switched current pulses are presented. The principle of constructing high-power DLD switches with independent triggering of dynistors, which is based on the use of a single-turn saturable-core choke in the power circuit and a saturable-core isolating transformer in the DLD triggering circuits, is described. A DLD switch with an operating voltage of 8 kV is considered, which can switch current pulses at a frequency of 2 kHz with an amplitude of 1.5 kA and a duration of 200 ns.

A nanosecond-pulse generator with an optimized diode switch

A diode-transistor generator of high-voltage nanosecond pulses, which is based on an inductive energy storage and an opening switch in the form of an assembly of drift step-recovery diodes (DSRDs) connected in series, is considered. It allows switching of a voltage pulse with an amplitude of 12 kV and a rise time of 4 ns into a load of 75 Ω at a frequency of 10 kHz. The results of investigations of the process of disabling DSRDs with different thicknesses of the base regions and different diffusion-layer profiles are presented. The design of optimized DSRDs with reduced energy losses during disabling is described. It is shown that the use of an assembly of optimized DSRDs in the developed generator provides a twofold increase in the limiting switched energy.

“A high-frequency semiconductor generator of high-voltage nanosecond pulses”

A high-frequency generator of high-voltage nanosecond pulses based on an assembly of drift step-recovery diodes is described. A circuit that includes parallel transistor chains for the formation of forward and reverse currents of drift diodes is presented. The results of tests of this generator are presented. Voltage pulses with an amplitude of 2.5 kV, a duration of 2 ns, and a pulse repetition rate of 300 kHz were obtained across a 50-Ω load.