SU473301A2 - Diode transistor switch - Google Patents

Description

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The invention relates to a pulse technique, in particular, to devices for accurately switching analog and discrete signals.

Basically auth. St. No. 320934 describes a diode-transistor switch containing a diode-resistor bridge with a storage capacitor in the diagonal and a compensated interrupter on two transistors, the collector-base transitions of which are connected to the diagonal of the bridge.

In the proposed key, the base of the compensated transistor chopper is connected to the key input via a source follower, the drain of which is connected to the common bus, and the load resistor through the diode to an additional source of switching voltage.

This makes it possible to increase the speed of the key when operating on a capacitive load.

FIG. 1 is a schematic diagram of a key; pas figs. 2 - stress diagrams.

The key consists of a compensated chopper on transistors 1 and 2, a protective diode 3, a bridge with diodes 4 and 5, resistors 6 and 7 and a capacitor 8 in the diagonal, switching diodes 9-11 and a source follower on a field-effect transistor 12 with a load resistor 13, and also the discharge diode 14.

The key works as follows. Switching voltages Ukg, Ukio (Fig. 2) are applied to diodes 9-11. There are four modes;

1. Private key mode (Fig. 2, interval a). A negative potential Uh.9 - (- E is supplied to diode 9, diodes 10 and 11 -

zero potential U ,,. At the same time, diodes 4, 5, 9, 10 are open, 3 and 11 are closed. A negative potential appears at the bases and collectors of transistors 1, 2. As a result, transistors 1, 2, 12 are closed, and the circuit

input / output is broken.

During this time, capacitor 8 is charged through E1SUES 4, 5, 9, 10 and resistors O and 7 to a negative potential Uh9 (-) - The charge polarity is indicated by

FIG. one.

2. Active mode (Fig. 2, interval b). A negative potential Ui; s (-) is applied to diode 9, and diodes 10 and 11 to a positive potential Ukio Ei. As a result

Ptpt is supplied to the composite repeater on the field transit; 1 stor 12 and transistor 2, which transmits the amplified signal from the output to the input. Diode 3 is closed. The capacitive load is rapidly charged from the signal source through a composite repeater, but the transmission accuracy is low.

The storage capacitor 8 is charged to an even higher potential + -Uhio + E. Diode 14 is needed to accelerate the transmission of a negative differential and opens for a short time in case

and PH3. Passive mode (Fig. 2, interval c). The control potentials Uk9 and f /; uo are zero. Diodes 4, 5, 9, 10, And, 14, the transistor 12 is de-energized, and the storage capacitor 8 discharges through resistors 6, 7, diode 3 and collector-base transitions of transistors 1, 2.

As a result, transistors 1 and 2 open in an inverted mode with low apparent resistance, with an increased skip accuracy of the switched signal from the input to the output.

4. The transmission mode of the negative front. In the private key mode, when the voltage on the capacitive load decreases, the voltage on the output of the key due to the discharge of the load capacitance through the diode 14 and the input of the repeater 12 decreases to a drain voltage that is slightly higher {UPh (Fig. 2, interval

d). If the voltage t / output becomes lower than t / Bx, the information is transmitted via the key in the modes described above (intervals b, c). Thus, the diode-transistor switch first works as an active on the repeater, quickly transferring “roughly the parameter value, and then, switching to the passive mode, transmits its exact value. Since the amplitude difference between

the amplitudes of the naked signal transmitted in the active and passive modes are small, the transition process is much shorter than the transition process with a purely passive mode of operation of the key built according to the known

scheme (i / o in Fig. 2).

Subject invention

Diode-trapzistorny key on author. St. No. 320934, characterized in that, in order to improve speed when working on a capacitive load, the base of a compensated transistor chopper is connected to the key input via a source follower, the drain of which is connected to a common busbar, and the load resistor is connected via a diode to an additional source of switching voltage.

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