SU875595A1 - Pulse generator - Google Patents

Description

(54) PULSE GENERATOR

one

The invention relates to a pulse technique and may find application in automation systems and radio electronic systems.

NIKI. .

Known pulse generator, assembled according to the scheme of Royer 1.

Also known is a pulse generator containing pulse times of back-up bridges, an output transformer with feedback windings included in the pulse-time branches of master bridges, and a switching transistor, with diodes shunting the base-emitter junctions of these transistors.

The bases of each of the switching transistors through the time, drive capacitors, feedback windings, and time, drive resistors are connected to collectors oppositely connected to the “transiting transistors” and to the collectors of their own switching transistors through diodes, additionally introduced resistors, and time set resistors, and the winding terminals the feedback through the diodes is connected to an additionally introduced variable resistor connected between the poles of the power source forming together. with the corresponding primary windings of the transformer, the second branches of the time of the driving bridges 2.

However, the known generators are unstable in operation as a master oscillator and there is a significant no-load current in them.

The purpose of the invention is to increase the stability of the generator and reduce the current consumption when resetting

 loads in a wide range of operating temperatures.

This goal is achieved by the fact that in a pulse generator containing two switching transistors, a transformer with output and feedback windings, the bases of each of the switching transistors through a series-connected diode, a resistor and a driving resistor are connected

20 with collectors of the same transistors, which are connected to the power supply bus, via the corresponding output transformers of the transformer, to vol. connection points of the resistor and

25 time of the master resistor, the corresponding series-connected feedback winding and the time of the master capacitor are connected, the emitters of the switching transistors are combined and connected to a different power supply bus, parallel to the base-emitter transitions of the switching transistors, a capacitor and an additional resistor are connected, the base of each switching transistor through the second additional the resistor, and the collector through an additional plug-in diode to the corresponding second terminals the time specifying the condensate moat., wherein additional diodes included in a direction concordant with Bazo-collector junction switching transistors.

The pulse generator consists of a transformer 1, ime of the winding 1-1, 1-2, 1-3, 1-4, 1-5, switching transistors 2 and 3, the time of the setting resistors 4 and 5, the time of the setting capacitors 6 and 7 , resistors 8–13, diodes 14 and 15, power supply 16, diodes 17 and 18, and capacitors 19. and 20.

The device works as follows.

A capacitor b is charged, the charge current of which flows from the plus source 16 through the winding 1-4 to which voltage develops, numerically equal to the voltage of the power supply 16, then through time the setting resistor 4, winding 1-1 according to the signs a capacitor 6, a resistor 8, a base-emitter junction of transistor 2 and a minus source 16. A transistor 2 opens and almost the entire voltage of source 16 is applied to the primary winding of transformer 1-3, on winding 1-5 of which one of the half wave oscillations. The duration of this half-wave is determined by the charge time of the capacitor 6 to a holding voltage equal to the voltage of the feedback winding 1-1 of transformer 1. Until the voltage on the capacitor 6 is fixed, the diode 15 is closed by the sum of the reverse voltage on the capacitor 6 and feedback winding 1-1. In the process of capacitor 6 capacitor 6, the voltage on a non-growing and, when the sum of the voltages on the capacitor 6 and the winding 1-1 becomes zero or slightly more than zero, diode 15 opens, fixing the voltage of the capacitor 6 (the base current of transistor 2 tends to zero ) and, opening the transistor 3 due to the base current flowing through the resistor 13 and diode 15. As a result, the avalanche process of unlocking the transistor 3 and locking the transistor 2 begins. This process is further accelerated due to the action of the winding of feedback 1-1, as this direction The voltage across it changes by 180 °, and it becomes consistent with the fixed voltage of capacitor 6. Condenser 6 overcharges, causing current to flow through the circuit: capacitor 6, winding 1-1, resistor 13, diode 15 , base-emitter junction of transistor 3, capacitor 19, resistors 10 and 8 5 and again capacitor 6. Thus, the output pulses are formed on winding 1-5 with steep fronts due to sharp unlocking at this time stage of transistor 3 and forced locking of transistor 2 .

The dynamics of these processes repeats and takes on a periodic nature, and on winding 1-5 Transform To 5 Pz 1, rectangular bipolar pulses are produced with steep fronts due to the presence of strong positive feedback at the moments of switching transistors 2 and 3.

Q When the pulse generator operates as a master oscillator of a power amplifier at higher switching frequencies, the input basic circuits of which are the load rio

essence of a dynamic nature, there are requirements for increased stability of the pulse generator. To do this, it is necessary to provide the necessary current value of the base of the switching transistor, corresponding to

0 load value at each given

instant for a given ambient temperature. Thus, the base current value must be chosen for the largest load and for the lowest temperature. Resistors 8 and 9 and diodes 17 and 18 largely allow the stabilization of the saturation of the switching transistors to provide a dynamic and temperature-dependent nature of the base current. However, with a complete load shedding, their action is not enough due to excessive redundancy of the base currents. The introduction of capacitors 19 and 20 introduces some

5, the time delay of the switching on moment of one switching transistor, which leads to the reduction of the overlapping currents. The condition for selecting the value of resistors 8 and 9 is that the voltage drop across resistor 8 or 9 is equal to the magnitude of the solution of the volt-ampere characteristic (voltage) of diode 17 or 18 at maximum load, minimum ambient temperature and zero base-collector voltage (boundary mode a) switching transistor.

Claims (1)

1. Authors certificate USSR 468359, cl. H 03 K 3/281, 1973. 2, USSR Author's Certificate No. 536591, cl. H 03 K 3/26, 1974 (prototype) ..