SU748812A1 - Emitter-coupled unlike-conductivity transistorized trigger - Google Patents

Description

The invention relates to a pulse technique and can find application in electronic equipment with a low level of energy consumption from power sources.

Known trigger with emitter coupling, ⁵ assembled on transistors of different types of conductivity £ 1]> This device contains input and output transistors of opposite conductivity, an emitter follower, resistors, the collector of the input transistor connected to the base of the output transistor and to the collector of the emitter follower transistor. This device is characterized in that the emitter of the output transistor is connected directly to the emitter of the transistor of the emitter follower, whereby emitter coupling is realized. The device has two response thresholds set using variable resistors, one of which is included in the base circuit of the emitter follower, and the other in the emitter circuit of the input transistor. The known device ensures the absence of a signal at the output when the amplitude of the input signal is greater than the upper level or less than the lower level.

The disadvantage of this trigger is its low efficiency.

By technical nature and circuit design, the closest to the proposed device is a trigger with emitter coupling, which contains input and output stages assembled on transistors having a mutually opposite type of conductivity {2]. In this case, the collector of the input stage transistor is connected to the base of the output stage transistor, from which the output signal is taken from the collector load resistor. The emitters and base of the input and output stage transistors are connected to the opposite busbars of the power supply through resistors. The emitter coupling is implemented using a communication resistor connected between the emitters transistors. In the initial state, both transistors are closed, and the input signal supplied to the base circuit of the input transistor causes the transistors to unlock and tilt the device over a period of time until the input signal level exceeds the threshold of the circuit ”. In this case, a rectangular pulse is generated in the collector circuit ^{5 of the} output transistor .

The main disadvantage of the known device is its consumption of energy from the source of power. condition.

The purpose of the invention is to ensure the absence of energy consumption from power sources in the initial state.

"The goal is achieved in that a trigger with ₁₅ emitter coupling on transistors of different types of conductivity!" containing input and output transistors, emitters and bases of which are connected through resistors to the corresponding buses of the pit-.jo source, and the collector of the input transistor is connected to the base of the output transistor, a collector load resistor connected between the power supply bus and the collector of the output transistor, the resistor is connected 25 hey, one output of which is connected to the emitter of the output transistor, an additional transistor and an isolation diode are introduced, and the emitter of the additional transistor is connected to the bus of the pi source voltage, the base - to the collector of the output transistor, and the collector - to the connection point of the second output of the coupling resistor with the first electrode of the isolation diode, the other electrode of which is connected to the input transistor emitter-35 ·.

The device diagram is shown in the drawing.

The device contains an input transistor 1, an output transistor 2, an additional transistor 3, an isolation diode 4, resistors 5-10.

The device operates as follows 748812 so that when the input signal exceeds the threshold level of the circuit due to the amplification of the input signal by transistors 1-3, a supporting voltage is applied to the diode 4, the diode is biased in the forward direction, and the positive feedback circuit closes, an avalanche-like develops in the circuit process, causing the circuit to tip over. In this case, transistors 1-3 go into a saturation state.

In the process of decreasing the input signal to a threshold level, transistor 1 exits the saturated state, the potential of its collector increases, leading to a decrease in the base current of transistor 2, which in turn leads to a decrease in the potential of its collector and blocking of transistor 3. Since the diode is isolated at this stage of operation, it is shifted in the forward direction, the positive feedback circuit is closed, and when transistor 1 exits saturation, an avalanche-like reverse rollover process develops in the circuit. This process continues until the locking of diode 4, after which the positive feedback circuit is broken, and the circuit returns to its original state.

Since the emitter of transistor 3 is directly connected to the bus of the power source, and the operating point of this transistor moves during the operation of the circuit from the cut-off region to the saturation region, the pulse amplitude on the collector of this transistor practically coincides with the voltage of the power source and the utilization factor of the supply voltage is little different from one, turning out to be significantly larger than in the known device.

zones.

In the initial state, the transistors 45 1-3 are closed, and the isolation diode 4, turned on in the opposite direction, prevents the current from flowing through the divider formed by the resistors 7-9. There is no energy consumption from power supplies 50 in the initial state accurate to the thermal currents of transistors and a diode isolation. When a positive polarity input signal is supplied to the base circuit of transistor 1, this transistor 55 opens, causing the opening of transistor 2, and then the opening of transistor 3. The values of resistors 7-9 are selected

Claims (2)

1. USSR author's certificate number 464069, cl. H 03 K 5/08, 1975. 2. Perlov B, V. Pulse devices on transistors with different types of conductivity. M., Energie, 1972, p. 7O, Fig. 2-1 d (prototype).