SU1547054A2 - Transistor gate - Google Patents

Abstract

The invention relates to electrical engineering, in particular to electronic devices controlling elements of automatic systems and secondary power sources. The power output transistor contains a cathode 3 feedback, resistive shunt 4, input transistor 6, shunt resistors 7, 10, current stabilizing transistors 9, 8, 11, resistors 12, 13, 16, 17, 18, 22, power supply 14, current limiting A diode 15, a control input 19, a field-effect transistor 20, a capacitor 21. The introduction of a power field-effect transistor 23, resistors 24, 25, and a capacitor 26 accelerates the switching on of the power output transistor, as well as accelerates switching it off, which leads to a general increase in the speed of the transistor key. 1 il.

Description

The invention relates to electrical engineering, in particular to electronic devices controlling elements of automatic systems and secondary power sources.

The purpose of the invention is to increase the transponder switch.

The drawing shows an electrical circuit of a transistor switch.

The transistor switch contains the output power transistor 1, the output terminal 2, the collector of transistor 1 is connected to the cathode of feedback diode 3, and the emitter of transistor 1 "Through the resistor 4 is connected to the minus bus source and output terminal 5, the base of the power output transistor 1 is connected to the emitter of the input transistor 6 l through the first resistor 7 - with a minus power supply bus. The base of the transistor 6 is connected to the anode of the feedback diode 3, collectors of tostabilizing transistors 8 and 9, and through the second resistor 19 to the minus bus of the power supply. The emitter of the transistor 8 is connected to the base of the criss-suppressor 11 and the base-transistor 9, the base-emitter junction of which is bridged by resistor 2f and the emitter t-transceiver 13 is connected to the positive side of the power supply 14 and via a current-limiting diode 35 to the collector of transistor 6 The power supply circuit of which includes a resistive divider consisting of resistors 16 and 17, the connection point of which is connected to the emitter of transistor 1I, whose collector is connected to the base of transistor 8 and through resistor 18 to control input 19. Drain of field-effect transistor The 20 p-junction is connected to the base of the power output transistor, the gate is connected via capacitor 21 to control input 19 and through resistor 22 to the source and negative bus of the power supply. The source of the power field-effect transistor 23 is connected to the collector of the power output transistor 1, its drain is connected to the output terminal 2S and the gate through the resistor 24 is connected to the resistor 25, which is connected to the positive power bus 14, and the capacitor 26, which is connected to the power bus 27, .

Transistor key works as follows.

In the presence of a logical signal 1

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0

0

five

0

five

On input 19, the power transistor is closed. In addition, the additional capacitor 26 is charged to the value of the power supply voltage. The same potential is applied to the gate of the power field-effect transistor 23. Since the source circuit is broken and the load voltage is applied to the drain, a cut-off voltage of the power field-effect transistor is applied to the source.

23and it is closed. When applied to the input 19 of the logic O, the power transistor opens, and the residual voltage from the collector, the power transistor 1, which is less than the voltage across the capacitor 26, is applied to the source of the transistor 23. Under the action of this voltage pn the course of the field-effect transistor 23 is mixed in the forward direction and a current flowing through it is determined by the value of the resistor 24. The power field-effect transistor 23 opens and its drain-gate capacitance through the open drain-source channel is discharged.

The discharge current flows through the resistor 24 and the capacitor 26, discharging it. Selecting the value of the auxiliary capacitor so that the voltage on it after the discharge coincides with the voltage of the divider on the resistors

24 and 25 in a steady state mode, it is possible to achieve a minimum turn-on transition time, i.e. ready power transistor switch. to shutdown. Since the current through resistors 24 and 25 in the steady state is much less than the load current, it does not affect the operation. the control circuit of the power transistor J, and the low output impedance of the power field-effect transistor 23 improves the stability of its operation.

o In the presence of a logical signal 1

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 ipig) 19 transistors at the input

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8 and 9 are closed, the transistor 6 is also closed, therefore, the power transistor 1 is also closed. There is no current consumption in the power circuit, which allows the use of a transistor switch in the modes of a smooth increase of the supply voltage.

When applied to the input 19 of the logical O (0) through the base circuit of the transistor 8 through the resistor 18 current flows. The voltage drop across the resistors 12 and 13 from the emitter current of the transistor 8 opens the transistor 11, the negative feedback closes and the transistor 8 enters the current stabilization mode, because as the emitter current of the transistor 8 increases, the voltage across the resistors 12 and 13 increases, causes an additional opening of the transistor 1 1, which reduces the base current of the transistor 8. Under the action of the collector current of the transistor 8, a voltage drop appears on the resistor 10, which opens the transistor 6. The voltage drop across the resistor D 16 from the collector current of transistor 6 decreases the collector current of transistor 11 ,. the transistor 8 additionally opens and the voltage drop across resistor 12 increases, which further opens up transistor 9 and, as a result, transistor 6. The process of increasing the collector current of transistor 9 and, consequently, transistor 6 will continue until diode 3 will open, which will occur if the voltage on the collector of the power transistor 1 is less than the voltage on the base of the transistor 6 by the amount of voltage drop on the diode 3, after which an increase in the collector voltage of transistor 9 will not cause velichenie current of transistor 6. The circuit will come to ustanovivshemus mode

If diode 3 does not open, then when the maximum collector current of transistor 6 is reached, the voltage on resistor 17 becomes greater than the voltage on diode J5, diode L 5 opens and the further increase in collector current of transistor 9 stops. The scheme will come to another steady state.

When the logical 1 signal arrives at the input 19, the 8% 9 and 6 transistors are closed, the power transistor 1 is locked, the source circuit of the power field signal

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transistor 23 is cut off, it is closed, and auxiliary capacitor 26 is charged by the drain current of the capacitor, the drain-gate of transistor 23 to the original voltage value.

Since the cut-off voltage of the power field-effect transistor 23 is much less than the load voltage (voltage

JQ drain of the transistor 23), and only this voltage is applied to the power transistor 1, it becomes possible to select it with a lower voltage and, therefore, more quickly J5. Since the speed of the transistor switch determines the speed of the bipolar power transistor, it is possible to increase the speed of the entire transistor.

20 transistor key.

In addition, the presence of a direct current through the pn-junction of a power field-effect transistor is reduced (compared to a grounded gate circuit)

25, the drain-source channel resistance, which leads to a decrease in the residual voltage drop on the key as a whole.

Formulas of the invention

Transistor Key Auth. St. No. 1476604, different from the fact that, in order to increase speed, a power field-effect transistor with a pn-junction, an additional capacitor, the fifth and sixth resistors are introduced into it, the source of the power field-effect transistor t being connected to the collector of the output power transistor, the gate A resistor is connected to the first terminals of the sixth resistor and an additional capacitor, the second terminals of which are connected to the positive and negative wires of the power supply, respectively, and the drain of the power field-effect transistor is connected to the output t ranzistor key.

Claims (1)

Transistor key for author. St. No. 1476604, due to the fact that, in order to improve performance, a power left-side transistor with a pn junction, an additional capacitor, a fifth and sixth resistors are introduced into it, and the source of the power field-effect transistor is connected ι ' with the collector of the output power transistor, the gate through the fifth resistor is connected to the first terminals of the sixth resistor and an additional capacitor, the second terminals of which are connected respectively to the positive 45 and minus tires of the power source, and the drain of the power field-effect transistor is connected to the output of the transistor switch.