SU875633A1 - Electronic switch - Google Patents

Description

(54) ELECTRONIC KEY

I

This invention relates to automation electronics. and can be used for switching DC circuits.

An electronic switch is known comprising a power transistor, an input transistor, a control circuit and an additional voltage source 1.

Its disadvantage is the complexity caused by the presence of an additional voltage source connected between the collectors of the power and input transistors.

The closest technical solution to the invention is an electronic key containing a transistor, the emitter of which is connected to the base, and the collector to the collector of the transistor is a Darlington circuit 2.

The disadvantage of this electronic key is low efficiency in steady state due to the fact that the power transistor cannot be in saturation mode.

The purpose of the invention is to increase the DPD of the electronic key when operating in the steady state mode.

The goal is achieved by the fact that in the electronic key containing the first transistor, the emitter of which is connected to

the base of the second transistor, the collector of which is connected via a resistor to the power supply bus, and the emitter is connected to another power supply bus, a diode is connected, the cathode of the diode is connected to the collector of the first transistor, and the anode to the collector of the second

 transistor.

In such an electronic key, the power transistor operates in the current mode at a steady-state load current.

The drawing shows the principle10 on the electronic circuit of the electronic key.

The electronic key contains a transistor 1, the emitter of which is connected to the base of transistor 2, the collector of transistor 2 is connected to the diode 3 channel and the resistance

1 load 4. The power supply is connected to another load terminal 4 and to the emitter of transistor 2. Transcendor 1 is supplied with an INPUT signal.

To switch the key into the base of the transistor 1, an input current is supplied equal to the ratio of the starting current of load 4 and the product of the current gain factors for the transistor I and 2. The residual voltage on the key at the starting current of load 4 is equal to the sum of the voltages on diode 3, base emig, p of transistor 2 and collector-emitter pins of transistor 1. After the start-up mode is completed, the load current 4 decreases and the input current is sufficient to saturate transistor 2. Turning on the diode between collectors of transistors 1 and 2 provides p bench saturation of the power transistor 2, which leads to increased efficiency of the key under steady load current without complicating the circuit and a high coefficient usnleni current at starting load currents. This makes it possible to increase the ratio of the starting current to the steady-state in the switching devices.

4-0

Claims (2)

- About the invention The electronic key containing the first transistor, the emitter of which is connected to the base of the second transistor, the collector of which is connected via a resistor to the power supply bus, and the emitter is connected to another power supply bus, characterized in that in order to increase the efficiency in the established mode The collector of the first transistor is connected to the cathode of the diode, the anode of which is connected to the collector of the second transistor. Sources of information taken into account during the examination 1. USSR author's certificate No. 632086, cl. H 03 K 17/00, 1978. 2. Stepanenko I.P. Fundamentals of the Theory of Trans. resistors and transistor circuits. M., “Energie, 1973, p. 221.