SU272686A1 - - Google Patents

Description

The proposed converter can be used in automation schemes as a master oscillator of stable frequency or voltage-frequency converter.

In the known push-pull magneto-transistor and converters on one transformer and two transistors with a voltage limiter shunting the transformer windings, and a switching magnetising force limiter, the planar voltage of the output voltage pulses is formed under the conditions when one of the transistors (open-circuit transistor) is in saturation mode. In this case, the transient switching of the shoulders due to the resorption time of the transistor is ignored and the accuracy of fixing the maximum value of the collector current, which determines the magnitude of the magnetizing force and, accordingly, the switching flow of the core, is not ensured. The absorption time and the maximum value of the collector current under the specified conditions significantly depend on the static and dynamic parameters of the transistor. This feature of the operation of such circuits determines the component of the frequency error of self-oscillations of the generator, caused by the instability of the parameters of transistors.

The component error is almost not compensable due to the randomness of the processes of temperature and temporal measurement of the parameters of the transistor.

In the proposed converter, for reducing frequency component error by completely eliminating the saturation mode of the transistors and almost completely eliminating the dependence of the maximum switching magnetizing force on the transistor parameters, the limiter and the switching switching power are connected in series to the emitter circuits of the transistors.

In order to extend the functionality, the magnetizing switching force limiter is designed as a current-stabilizing two-terminal circuit on a transistor, the emitter of which is connected to a source of steady-state current.

FIG. 1 shows a modification of the proposed converter circuit designed to operate as a constant frequency master oscillator; in fig. 2 is a modification of the circuit designed to operate as a voltage-frequency converter; in fig. 3 - timing diagrams explaining the work of the proposed scheme.

Voltage suppressor on diodes 6, 7 and zener diode 8, jokes the collector winding, limit switch N. C. Switch (resistor) 5 connected to the emitter current circuit of transistors. The power supply of the circuit is carried out from the source of the voltage 10.

In the diagram in FIG. 2, the source of the voltage to be transformed 8 serves as a stabilizer. At the same time, to maintain a constant level11 of the emitter current of 4 to 5 transistors when the voltage changes instead of a resistor, a stabilizing current of two-pole 9 on the transistor 11 operating from an additional constant source is used current 2. The rest of the Daina modification of the scheme fully coincides with the previous one.

The rate of change of the gok in the core

set by voltage stabilization Uo voltage limiter. The emitter, and practically the collector currents of the open-shoulder transistor are set by the emf induced by the base winding and the resistance of the resistor in the emitter circuit:

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The excess collector current (the difference between the collector current and the current consumed by the collector winding of the transformer) goes to the voltage limiter:

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The incidence of the collector — the base of the acd transistor of the open shoulder retains the polarity at which the active mode of the transistor is maintained; for this emf The power supply must satisfy the condition:

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The stable operation of the circuit during the formation of a flat top of the output voltage pulse during the active state of the transistor is provided in this case with a voltage limiter: the low differential co-current of the limiter shields the winding, as a result of which the feedback loop transfer ratio remains less critical (for the regenerative to occur) process) despite the active mode of the transistor.

The saturation of the core leads to an increase in magnetizing force F; the collector current remains unchanged and the current / and. consumed by a voltage limiter

decreases. When the current / o becomes close to the bullet, the limiter leaves the stabilization mode, its differential resistance increases dramatically. As a result, the transfer coefficient of the reverse-loop loop reaches a critical value, and a regenerative switching process of the transistors occurs in the circuit (the transistor moving in the active state, goes into cut-off mode, and vice versa).

The magnitude of the magnetizing force at the moment of switching is determined by the specific value of the emitter current. It practically does not depend on the static and dynamic parameters of the transistor, provided that its gain is large enough: p

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Consequently, in the scheme under consideration, a voltage limiter also provides stabilization of the magnetizing switching force. The AFP core switching flow is accordingly stabilized. Thus, the circuit eliminates the

saturating the transistors, thereby speeding up switching processes and stabilizing the core switching flux; as a result, the frequency stability of the self-oscillations increases.

It should be emphasized that this effect is achieved due to the combination of a voltage limiter on the windings and an emitter current limiter (the use of any of them separately is known, but does not give a marked effect).

Subject invention

1. Magneto-transistor converter on a transformer and transistors e with a voltage limiter shunting the transformer windings and a magnetizing switching force limiter, characterized in that, in order to increase the stability of self-oscillations, the magnetizing limiter

switching forces are connected in series to the emitter circuit of the transistors.

2. The converter according to and. 1, characterized in that, in order to expand the functionality, the magnetizing limiter

The switching forces are made in the form of a current-stabilizing two-pole device on a transistor, the emitter of which is connected to a direct current source.

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