SU1385287A1 - Gate generator - Google Patents

Abstract

The invention relates to a pulse technique and can be used as high-power high-frequency generators of radio transmitting devices. The invention expands the frequency range of the device as a result of inserting diode keys to provide faster unlocking of the key element field-effect transistor and reducing the turn-on time of the power key element to eliminate through-currents. The key generator contains a driver 1, a matching unit 2, key elements 3 and 4, each of which contains a field effect transistor 5 (6), a bipolar transistor 7 (8) and a power diode 9 (10), resistors 11-14 and diodes 15- 18. The causative agent 1, like in the prototype, is close to a voltage generator and generates at the output two antiphase signals of the meander type with an amplitude sufficient to unlock the field-effect transistor. It can be made according to the scheme of low-power key amplifier and broadband pulse transformer. 2 Il. with S (L

Description

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The invention relates to a pulse technique and can be used as a powerful RF generators of radio transmitting devices.

The purpose of the invention is to expand the frequency range by introducing diode keys to provide faster opening of the key element field-effect transistor and reducing the delay time for switching on the power key element to eliminate through-currents.

FIG. 1 shows the scheme of the proposed device; in fig. 2 - diagrams of currents and voltages showing the operation of the device.

The device contains a pathogen 1, block 2 approval, key elements

cops 3 and 4, each of which contains a face of which can also be driven out by a field-effect transistor 5 and 6, a bipolar transistor 7 and 8, a power diode 9 and 10, resistors 11-14, and diodes 15-18. In this case, the output of the exciter 1 through

series-connected resistors 25 max out earlier.

13 and 11 (either 14 and 12), shunted by diode 17 (or 18), are connected to the input of the key element 3 (or 4), and the connection point of resistors 13 and 11 (or 14 and 12) is connected through 30 diode 17 (or 18 ) with the output of the key element 4 (or 3) and the input of the block 2 matching.

The causative agent t is close to the generator

voltage (R-R), provides on, c to the field gate valves, two antiphase signals of the type square, with an amplitude sufficient to open the field-effect transistor, and can be made in the form of a low-power key amplifier and a broadband (pulsed) transformer;

The matching unit 2 serves to match the key elements with the load, in particular, it can be made in the form of a transformer, the middle point of the primary winding of which is connected to a power source, and its extreme outputs are the inputs of the matching device, the outputs of the secondary winding of which are its outputs.

The essence of the operation of the device is as follows: until one of the key elements, for example 3, is turned off (Fig. 1), i.e. its output voltage is small and equal to the residual voltage on the bipolar transistor 7 (U ctO), the diode 18 does not allow the potential of the common output

resistors is unacceptable, since the actual residual voltage on the key element at collector currents of 10-20 A can reach a value of 2-3 V, and

40 The value of the threshold voltage of a field-effect transistor often lies in this voltage range (for example, for a KP 904 U transistor of the 1 V type), and the locking condition of the field-transistor of the resistor in this case is impossible.

Let us determine the values of resistors R, and Rg (Fig. 1) in the case of the example corresponding to that considered for the known device. The proposed technical solution of the key generator is not critical to the choice of the resistance value connected to the gate of the field effect transistor. The maximum value of resistor 11 (12) R is determined by the formula

t, C 50 NS, whence R, ", Om50

0

resistors 12 and 14 exceed U ,,; .., under the influence of which the resistor 12 recharges the input capacitance of the field-effect transistor 6 of another key element through a resistor 12. to (the value of resistor 12 (11) determines the on-delay of the field-effect transistor and since U g "UBX. Motcc then the value of resistor 12 (11) is substantially less than the value of resistor 12 (11) in the known device). After switching off the key element 3, the diode 18 is closed and 5 further recharge of the input capacitance of the field-effect transistor occurs under the influence of the potential U gj through series-connected resistors 12 and 14 (11 and 13), the total veran is significantly less than the value of resistor 12 (11) R in a known device . Consequently, the voltage across the gate of the field-effect transistor will be reached in the known device, which will provide a lower value of the residual voltage on the key element, and hence a smaller amount of static losses. Thus, the proposed device has a high efficiency compared with the known device.

The connection of the non-optic diodes 17 and 18 is unacceptable, since the actual residual voltage on the key element at collector currents of 10-20 A can reach 2-3 V, and

0 The value of the threshold voltage of a field-effect transistor often lies in this voltage range (for example, for a KP 904 U transistor type 1 V), and the locking condition of the field-effect transistor in this case is impossible.

Let us determine the values of resistors R, and Rg (Fig. 1) in the case of the example corresponding to that considered for the known device. The proposed technical solution of the key generator is not critical to the choice of the resistance value connected to the gate of the field effect transistor. The maximum value of resistor 11 (12) R is determined by the formula

t, C 50 NS, whence R, ", Ohm0

The value of resistor 13 (14) R. must be determined from the permissible additional current 1dop through the open key element along the following circuit: exciter, resistor 13 (14) RI, diode 17 (18), open key element 4 (3). Let the amplitude of the output voltage of the exciter U cflO V, the maximum current of the key element

I k. er max U A, 1 dop / 1 i.E.MakS

 0.01 (1%). Then

iAon (UM- and Ost - UD) / R “;

R f 50 Ohm;

R R + R, ci 130 DM.

After one of the key elements is turned off, the voltage at the input of the other is changed according to the formula

i - t cl

. Ugx - E)

with a constant time Φ г g RC, significantly less than the time constant of the known device, which ensures that the input voltage increases to 0.99 U at the moment when the maximum current passes through the key element (tt 5 cd + T / 4 ).

Claims (1)

Invention Formula Key generator containing pathogen, matching unit, pers. five 0 five n five the first and second diodes, the first and second key elements, consisting of an irradiation diode, field and bipolar transistors, the emitter of the bipolar transistor connected to the common bus and the anode of the power diode, the base to the source, and the collector with the cathode of the power diode and with the drain of the field-effect transistor, the gate of which is the input of the key element, and the drain is its output, the output of each key element is connected to one of the inputs of the matching unit, and the input of each key element with the first output corresponds to a resistor and an anode of the corresponding diode, the cathode of each of which is connected to one of two exciter exciter codes, characterized in that, in order to expand the frequency range, the third and fourth diodes, the third and fourth resistors are inserted in it, the first output of the third resistor and the anode The third diode is connected to the second output of the first resistor, and the second output of the third resistor is connected to the cathode of the first diode, and accordingly the first output of the fourth resistor and the anode of the fourth diode are connected to the second output of the second life line. ora, and the second terminal of the fourth resistor - to the cathode of the second diode, the cathode of the third diode is connected to the output of the second key element, and the fourth diode cathode - a yield of a key element. D KAIJ -f (iC fifCY FIG. 2