Generator of advancing current pulses based on controlled semiconductor diode-thyristors for digital ferrodiode and ferrotransistor circuits

GENERATOR OF ADVANCING CURRENT PULSES BASED ON CONTROLLED SEMICONDUCTOR DIODE-THYRISTORS FOR DIGITAL FERRODIODE AND FERROTRANSISTOR CIRCUITS

V. M. RAZIN, Yu. N. EFIMOV

(Presented by the scientific seminar of the Faculty of Automation and Computer Engineering)

At present, ferrodiode elements are finding fairly wide application in digital automatic devices and specialized computing machines. Considerable difficulties in the use of ferrodiode elements have been caused by the circuit for generating advancing current pulses. Existing generators have large dimensions, consume considerable power, and are not sufficiently reliable in operation. The use in such devices of controlled semiconductor diode-thyristors as switching elements makes it possible to create generator circuits free from the above-mentioned shortcomings. This paper gives a description of one of the possible versions developed by us for constructing a circuit of a generator of powerful advancing current pulses, which can be used both for supplying ferrodiode elements and for supplying ferrotransistor elements. As the switching elements in the generator circuit, thyristors of type D235B available to us are used. The main forming circuit with the power supply has the form shown in Fig. 1. In this circuit the main forming energy-storage element is a 5-section artificial forming line consisting of capacitances \(C_1—C_5\) and inductances \(L_1—L_5\). Oscillatory charging of the line is carried out from the DC voltage source \(U_0\) through the charging inductance \(L_0\) and the blocking diode \(D_1\). Discharge of the line into the load \(Z\) is carried out through the thyristor \(D_4\) when a firing current pulse from the pulse transformer IT is applied to its control electrode. The resistance \(r\) serves to limit the current amplitude in the control-electrode circuit, while the diode \(D_2\) prevents the appearance of a voltage pulse of reverse polarity. A noninductive resistance \(R\) of small value in the load circuit is used for oscillographic monitoring of the shape of the current pulse in the load. The voltage proportional to the current is taken from point 1 and applied to the input of the oscilloscope. To terminals 3 and 4 of the pulse transformer IT, the control voltage is applied from the control circuits [1]. The part of the circuit in Fig. 1 enclosed by a dashed line is, in a certain sense, a unified subunit UM. By using such unified subunits, it is possible to build multicycle generators of advancing current pulses. By connecting to point 2 of the load subunits with different voltages \(U_0\), it is possible to generate in the load current pulses of different amplitudes according to a specified program.

The block diagram in Fig. 2 shows an example of a pulsed three-phase generator circuit for supplying digital computing devices built using a system of three-cycle ferrodiode elements. In this circuit, the channel conductors of the three-cycle system of ferrodiode elements are represented by loads \(z_1, z_2\), and \(z_3\). The main

Fig. 1. Schematic diagram of the generator

working advancing pulses are generated by the shaping circuits \(\Phi_1, \Phi_2, \Phi_3\), constructed on the basis of the circuit of Fig. 1 and triggered at inputs 1, 2, and 3 by pulses according to a specified program. The blocking

Fig. 2. Block diagram of a three-phase generator for supplying ferrodiode elements.
Fig. 3. Oscillogram of the current pulse on an active load.

pulses are generated by the shaping circuits \(\Phi'_1, \Phi'_2\), and \(\Phi'_3\), supplied from the voltage source \(U'_0\) with a lower voltage value in comparison with the source \(U_0\) for supplying the main working shaping circuits, since the current amplitude of the blocking pulses may be less than the current amplitude of the main working pulses. Control of the blocking shaping circuits \(\Phi'_1, \Phi'_2\), and \(\Phi'_3\) is also carried out at inputs \(1'\), \(2'\), and \(3'\), in accordance with the required program. The program generator of control pulses is not shown in Fig. 2. In cases where the current amplitudes of the main and blocking pulses can be made approximately equal, in the circuit of Fig. 2 it is sufficient to have three main shaping circuits \(\Phi_1, \Phi_2\), and \(\Phi_3\) and one supply source \(U_0\), while specifying the corresponding program of control pulses at inputs 1, 2, and 3.

Under laboratory conditions, the circuit of Fig. 1 was fabricated and tested. The shape of the current pulses obtained in this circuit is shown in the oscillogram of Fig. 3. The load \(Z_n\) in the circuit of Fig. 1 was an active resistance of 9 ohms with a series-connected inductance of about 20 μH. In various operating modes, with different ratios of the parameters of the forming line and the load, current pulses of approximately trapezoidal shape were obtained, with an amplitude of up to 10–20 A and a duration, at the level of 0.1 of the amplitude, from 10 to 20 μsec. The pulse repetition frequency was varied smoothly from 250 Hz to 5 kHz. These preliminary tests showed that the generator circuit operates quite stably and has small dimensions with a comparatively high efficiency. At present, a model according to the circuit of Fig. 2 has been fabricated and is undergoing laboratory investigation.

REFERENCES

1. L. M. Avdeenkova, N. V. Korolkov. Analysis of the operation and calculation of magnetic ferrite-diode elements for digital computers. Computing Center, Academy of Sciences of the USSR, 1962.