SU884088A1 - Pulse shaper - Google Patents

Description

(54) PULSE FORMER

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The invention relates to the generation of pulses and is intended for use in radio installations for producing high amplitude pulses with short fronts on a large capacitive load (circuits controlling electro-optical gates, oscillator light pulse generators, circuits for exciting dielectric films).

A pulse shaper is known that contains a charging resistor, a storage capacitor, two input sources, a load circuit and two avalanche transistors, as well as an additional transistor and a diode t 1

The disadvantage of such a former is its complexity and the small steepness of the fronts of the generated pulses.

A pulse shaper is known that contains input and output avalanche transistors, to the bases of which separate outputs of the pulse source and two discharge diodes are connected. The collector of the input avalanche transistor is connected to the connection point of the anode of the second discharge diode with the base of the output avalanche transistor, and the emitter connected to the cathode of the second discharge diode and the load, and the anode of the first discharge diode is connected to the collector of the input avalanche transistor, and the cathode of this diode is connected to the point of connection of the anode of the second discharge diode with the base of the output avalanche transistor 2,.

For this driver to operate, a separate source must be used that produces two pulses, one of which controls the switching on of the output avalanche transistor forming the front and the flat top of the output pulse, and the other controls the switching on of the input avalanche transistor forming the back front of the output ck pulse. 36 The discharge circuit of the load capacitor of this driver contains a sequence of included input avalanche transistor and two discharge diodes. The lack of ampli fi cation of the introduction of discharge diodes is caused by the use of transistors of the same conductivity type in the driver. This leads to an increase in the discharge time constant (the resistance of the transistor in the mode of avalanche breakdown is unity ohms) and the length of the falling front of the pulse being formed. Since the output signal is removed from the emitter of the output transistor, its potential is not fixed relative to the potential of the common bus. This requires the introduction of a transformer connection between the base of the output transistor and the source of pulses, which prevents the shaper of output pulses of even a long duration. The purpose of the invention is to increase the steepness of the fronts of the produced pulses and the range of their duration in the direction of increasing. To achieve the specified purpose, a pulse transformer containing input and output avalanche transistors was introduced, a differentiating transformer was inserted, the collector of the input avalanche transistor was connected to the load connection point and the collector of the output avalanche transistor with conductivity of the ANTICATED type, and the emitter of the output avalanche transistor Connected to not grounded. The source of the power supply, the base of the output avalanche transistor is connected to the secondary winding of a differentiating transformer, the primary winding of which is included in the collector circuit of the input avalanche transistor. The drawing is a schematic diagram of the former. The pulse shaper contains an input avalanche transistor 1, the collector of which is connected to the load connection point, consisting of resistor 2 and capacitor 3, with the collector of output avalanche transistor 4 with the opposite conductivity. The emitter of the output transistor 4 is connected to a non-grounded pole power supply, and its base is connected to the secondary winding of a differentiating transformer 5, the winding of which is connected between the ungrounded power supply pole and a resistor 6 connected to the connection of the collectors of transistors 1 and 4 with the load. 8 Shaper works as follows. In the initial state, the transistors I and 4 are closed, since the voltage Ej is chosen to be close, but lower than the avalanche voltage of the transistor. When a triggering pulse is applied to the base of the transistor I, the latter unlocks the avalanche transistor 1 and enters it into a test. When an avalanche transistor breaks through, a large current (unit-ten amperes) flows through it, leading to a very fast discharge of capacitor 3. i Upon completion of the discharge of capacitor 3, the current through the avalanche transistor decreases to the value E, / R (where R is resistance resistor 6) and the transistor is in the saturation state. Due to the need for power dissipation on the transistor .1 is small, the pulses on the load have a flat top. At the end of the input pulse, the transistor 1 is locked and the current flowing in the primary winding of the differentiating transformer 5 decreases from R to zero. In this case, a short negative polarity pulse is removed from the secondary winding of the transformer, which is fed to the base of the avalanche transistor 4 and starts it. With probr the avalanche transistor 4, the capacitor 3 is quickly charged before the a-supply voltage Ец and the circuit returns to its original state. The formation of a falling edge by the transistor 4 of the ghosting ifc1- -J- - - - J, after closing the transistor I, therefore the simultaneous opening of both transistors is automatically turned off. The use of transistors of different types of conductivity favorably distinguishes the proposed device from the indicated one, since additional elements (discharge diodes) are excluded in the charge and discharge circuits of the load capacitance, which significantly reduces the duration of the fronts of the generated pulses. For operation, the shaper does not require an additional source that generates separate pulses, including avalanche input and output transistors. The impulse on the load is generated when only one signal is applied to the input. Since the potentials of the emitters of both transistors in the proposed driver are fixed relative to the potential of the common bus, it is possible to easily carry out a galvanic connection between the source of the input signal and the base of the input transistor.

Invention Formula

A pulse shaper containing input and avalanche transistors characterized in that, in order to increase the steepness of the output impulses and their duration range upwards, a differentiating transformer is inserted into it, the collector of the input avalanche transistor is connected to the connection point of the load and the collector of the output avalanche transistor with the conductivity of the opposite type, and the emitter of the output avalanche transistor is connected to the ungrounded pole of the power source, and the base of the output la innogo grayzistora connected to the secondary winding of the transformer differentiator, pervshna winding is included in the collector circuit of the input avalanche traveiotora.

Sources of information taken into account during the examination

1, USSR Author's Certificate N9 508918, cl. H 03 K 5/01, 1976.

2. USSR author's certificate N 458990, cl. H 03 K 3/335, 1975 (prototype).

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Launch

Claims (1)

Claim A pulse shaper containing input and output avalanche transistors, characterized by gem, which, in order to increase the steepness of the fronts of the generated pulses and the range of their duration upwards, a differentiating transformer is introduced into it, the collector of the input avalanche granule ¹⁰ zisgora is connected to the connection point load and collector of the output avalanche transistor with the opposite type of conductivity, and the emitter of the output avalanche transistor is connected to the non-ground pole of the power source, and the base and the output avalanche transistor is connected to the secondary winding of the differentiating transformer, the primary winding of which is included in the collector circuit of the input avalanche transistor.