SU458090A1 - Pulse shaper - Google Patents

Description

one

The invention relates to the impulse technique and can be used to obtain high amplitude pulses with short fronts on a large capacitive load (oscillator backlight pulse generators, circuits for exciting dielectric films, circuits controlling electron-optical gates, etc. ).

A pulse driver named for them is known, containing input and output avalanche transistors, to the bases of which separate outputs of a source of pulses and two discharge diodes are connected.

The aim of the invention is to simplify the former and expand its functionality.

For this, the collector of the input avalanche transistor is connected via the first discharge diode to the connection point of the anode of the second discharge diode with the base of the output avalanche transistor, to the emitter of which the cathode of the second discharge diode is connected and the load is connected to the collector of the input avalanche transistor of the first discharge diode 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.

The drawing shows a schematic diagram of the shaper.

The pulse driver contains a source of rectangular pulses 1, input and output avalanche transistors 2 and 3, respectively, first and second discharge diodes 4 and 5, respectively, transformer 6, resistor 7 and load resistor 8, as well as load capacitor 9.

The shaper works as follows.

In the initial state, transistors 2 and 3 are closed, since the EC voltage is chosen to be close, but lower than the avalanche voltage of the transistor. When starting the circuit from the source of the rectangular pulses 1, this pulse through the transformer 6 unlocks the avalanche transistor 3 and introduces it into the elevation. When an avalanche transistor breaks through, a large current (units — ten amperes) flows through it, leading to a very fast charge of capacitor 9. At the end of the charge of capacitor 9, the current through the avalanche transistor decreases to the value equal to and the transistor is in the saturation state ( here, is the resistance of the load resistor 8). Due to saturation, the power dissipated at the transistor is much less than in conventional avalanche transistor circuits, and the pulses at the load have a flat top.

At the end of the required time interval, a short opposing impulse goes to the second avalanche transistor 2 (this impulse can be obtained by differentiating the almost rectangular pulse that triggers transistor 3). During the breakdown of the avalanche transistor 3, the capacitor 9 is quickly discharged through the opened diodes 4 and 5 and the avalanche transistor 2. At the same time, the dump on the diode 5 from the high discharge current reliably closes the avalanche transistor 3 even if unlocked the pulse on the primary winding of the transformer 6 is not finished. It also contributes to the very rapid output of the transistor 3 from the saturation mode.

In the proposed driver, the probability of failure of transistors 2 and 3 is significantly reduced. Both transistors are in avalanche mode for a very short time — the time of the fronts duration. Simultaneous switching of the transistors is automatically eliminated. The power dissipated by transistors 2 and 3 during the interwave between the impulses and during the formation of the peak is very small. The amplitude of the pulses is practically equal to k. The duration of the pulses can vary over very wide limits: from

The total duration of fronts to tens is hundreds of milliseconds. The recovery time is very short - practically it exceeds the duration of the front by the time the transistor 2 leaves the saturation mode.

The proposed shaper may allow to obtain pulses with an amplitude of more than 100 volts.

Subject invention

A pulse shaper containing input and output avalanche transistors, to the bases of which are connected the separate outputs of the source and pulses and two bit

A diode, characterized in that, in order to simplify the former and expand its functionality, the collector of the input avalanche transistor is connected to the junction point of the anode of the second discharge diode to the base of the output avalanche transistor through the first discharge diode diode and the load, moreover, an anode is connected to the collector of the input lavnnnogo transistor

the first discharge diode, and the cathode of this diode is connected to the connection point of the anode of the second discharge diode with the base of the output avalanche transistor.