SU886201A2 - Two-cycle transformerless cascade - Google Patents

Description

(54) TWO-TERM BESTRAISFORMATORY CASCADE

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The invention relates to automation and computing and can be used as an output power amplifier in servo systems, as well as in measurement systems, communication.

According to the main author. St. No. 262185 is known a push-pull transformerless cascade containing a composite dynamic load transistor and a transistor controlled by an input signal, connected in series via a direct current, the collector of the dynamic loading transistor being connected to one pole of the power source, its base is simultaneously connected to the collector through the diode to the emitter and directly to the collector of the transistor controlled by the input signal, the emitter of which is connected to the other pole of the source nutrition

However, the known push-pull transformer cascade has low efficiency.

The purpose of the invention is to increase efficiency.

The goal is achieved by the fact that a push-pull transformer cascade containing a dynamic load transistor and a transistor controlled by an input signal, connected in series with a direct current, the collector of the dynamic load transistor is connected to one pole of the power source, its base is simultaneously connected first resistor to

5, through the diode to the emitter and directly to the collector of the transistor controlled by the input signal, the emitter of which is connected to the other pole of the power source, an additional transistor is introduced, the emitter of which is connected to the base of the transistor controlled by the input signal, and the collector through parallel connected inductance and additional diode - to the emitter of the second transistor. The drawing shows the electric

15 scheme of the proposed cascade.

Claims (1)

A push-pull transformer-free cascade contains a composite dynamic load transistor consisting of a first 1 and a second 2 transistors, a transistor 3 controlled by an input signal, an additional transistor 4, a first 5 and a second 6 resistors, a diode 7, an inductance 8 and an additional diode 9. A two-stroke transformer-type cascade works as follows. In the absence of an input pulse, transistors 3 and 4 are locked, and 1 and 2 are open by the current flowing through the first resistor 5. At the output of the cascade there is a maximum positive output voltage, and on the collector of the additional transistor 4 there is a voltage equal to the potential difference between positive and negative by the power supply tires, i.e. 2Epit. When the input pulse is applied, the additional transistor 4 opens, the voltage on its collector becomes equal to zero and the entire voltage falls on the inductance 8. The current through it increases exponentially, determined by the constant inductance. After the turn-on delay time of the transistor 3, the latter begins to open, the voltage across the load and inductance decreases, and the current through the inductance increases. reaching a maximum value at the moment of almost complete opening of the transistor 3, and then begins to decrease gradually, since it cannot change abruptly. The inductance current is the collector current of the Additional transistor 4 and, neglecting the output current of the signal source, is the input current of the transistor 3. That is, after the transistor is almost fully opened, when the inductance current reaches its maximum value and begins to gradually decrease, the inductance itself becomes an additional source of emf (L d-i / dt sign), further lowering the output voltage of the cascade and forming a flat part of the output pulse. If the input pulse ends before the stored inductance energy 8 is consumed. After closing the additional transistor 4, the current is closed through the additional diode 9, eliminating the overvoltage on the collector of the additional transistor 4. When the low frequency signal is amplified or the signals are amplified with a low slew rate, the cascade is working as well as a circuit without a limiting resistor in the collector circuit of the input stage, providing a small output voltage. Thus, the introduction of new elements improves the efficiency of the proposed cascade. Claims of the invention Push-pull transformerless cascade according to aut. St. No. 262185, characterized in that, in order to increase efficiency, an additional transistor is inserted in it, the emitter of which is connected to the base of the transistor controlled by the input signal, and the collector is connected through a parallel inductance and an additional diode to the emitter of the second transistor. Sources of information taken into account during the examination 1. USSR author's certificate No. 262185, cl. H 03 F 3/26. 1968. g . A5 V7 AT)(. - nuiri