SU1451816A1 - Device for controlling transistor switching element - Google Patents

Abstract

The invention relates to a converter technique and can be used in electric motor control devices, in transmission devices, laser and other systems where semiconductor elements are used in switching mode. The purpose of the invention is to reduce power losses in the control circuit. When transistor 1 is turned on, positive potentials appear at the terminals of current transformer 2 connected to the cathode of diode 5 and to the positive terminal of capacitor 7. In this case, diode 4 opens and begins the accumulation of charge in its base through diodes 8 and the emitter-base transition begins to flow the direct base current of transistor 1. The values of the flowing currents are determined directly by the emitter current value of transistor 1. After the turn-off signal is applied to transistor 1 the emitter current begins to decrease, resulting in the voltage sign on the windings of the transformer 2 being measured

Description

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On the opposite, the potential at the junction point of diode 4 with the collector of transistor 1 becomes lower than the minus supply voltage and will remain so until the end of the resorption phase of minority carriers accumulated in the base region of diode 4 and restore its reverse capacitance.

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The invention relates to a converter technique and can be used in electric motor control devices, in transmission devices, laser and other systems where semiconductor elements are used in switching mode,

The purpose of the invention is to reduce power losses in the control circuit.

Figure 1 is a circuit diagram of a device for controlling a transistor switching element; on figa, b - the diagrams of the currents explaining his work.

The device for controlling the transistor switching element 1 contains a current transformer 2, the current winding of which is connected to the emitter of transistor 1 by one and the negative terminal of the supply voltage source is connected to the load transistor 3 and to the cathode of the diode 4, the anode of which is connected to the anode diode 5, shunted by a resistor 6, the cathode of which is connected to the first output of the output winding of the current transformer 2, the second output of which is connected to the negative output of the power source its voltage, the output of the output winding of the current transformer 2 is connected to the positive terminal of a capacitor 7, triggered by a chain of 8 diodes connected in series, the anode of the first of them connected to the positive terminal of a capacitor, and the cathode of the latter from the negative side of the circuit: emitter - transistor base 1, capacitor 7, transformer tap 2, minus power supply bus — reverse base current will flow. The capacitor 7 in this case provides an additional reverse bias voltage for the base-to-emitter transition of the transistor 1 in the closed state interval. 2 Il.

With a capacitor terminal and a transistor base, the second terminal of the load resistance is connected to the positive terminal of the power supply source.

The device works as follows.

When the transistor 1 is turned on

the terminals of the current transformer 2, connected to the cathode of diode 5 and the positive terminal of capacitor 7, have positive potentials, the diode 4 opens and begins the accumulation of charge in its base, through diodes B and the base-to-emitter transition begins to flow through the base transistor current 1.

The magnitudes of the flowing currents are determined directly by the emitter current of the transistor. After the switching off signal to the transistor, the emitter current begins to decrease, as a result of which the voltage across the transformer windings is reversed, the potential at the junction point of diode 4 with the collector of the transistor becomes below the negative supply voltage and will remain so until the end of the absorption phase carriers accumulated in the base region of diode 4, and restoring its reverse resistance. According to the emitter junction circuit - transistor base, capacitor 7, transformer 2 tap, the negative terminal of the power supply source will flow the reverse base current. Capacitor 7 npji this provides an additional ex. T

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Claims (1)

Claim A device for controlling a transistor switching element containing a current transformer, one terminal of the primary winding of which is connected to the negative terminal of the supply voltage source, and the other is used to connect a transistor to the emitter, whose collector through the load is used to connect the supply voltage source to positive output, the first and a second diode and a resistor, the resistor being connected parallel to the first diode, and the cathode of the second ₁₀ diode is designed to connect to the collector transistor, characterized in that, in order to reduce power losses in the control circuit, a capacitor and a chain of η diodes are connected from η in series, where η = 1, 2, 3, ..., and the first terminal of the secondary winding of the current transformer is connected to a common the cathode point of the first diode 2θ and the first output of the resistor, the common point of the second output of which and the anode of the first diode is connected to the anode of the second diode, the second output of the secondary winding of the current transformer is connected to the negative output of the supply voltage source, and the middle output through η point each of the series connected diodes which is connected in parallel kondensa2Q torus, connected to the base of the transistor connected as a source control signal.