SU900450A1 - Transistorized switching device - Google Patents

Description

I

The invention relates to a pulse technique and can be used in automation systems, telemechanics, in particular, in high-speed wide-range electrically conducting wires and tracking systems.

Known transistor switch, the contents of the device overload protection 1.

However, the known device has no protection when the transistor leaves the saturation.

The closest to the invention to the technical essence is a transistor switch containing a power transistor, the base of which is connected via a resistor to the input bus and through a collector-emitter junction of the protection transistor to a common bus, a current limiter in the power circuit, a delay element and a threshold element connected through diode to the combined terminals of the power transistor and the load 21.

However, this device has a delay in the operation of the protection node, which reduces reliability.

The aim of the invention is to increase reliability.

For this, a transistor switch containing a power transistor, the base of which is connected via a resistor to the input bus and through the collector-emitter junction of the protection transistor to a common bus, current limiter in the power circuit, delay element and threshold element connected via a diode and a combined output the power transistor and the load, an additional key is introduced on the transistor, the base of the transistor of the additional key is connected to the output of the delay element, and the electromotive-emitter circuit is connected hydrochloric combined bus terminals of the threshold element and the diode. 39 The drawing shows a circuit diagram of the proposed device. The device contains power transistors 1TZ, connected in parallel, resistors 4t6 and diode 7 are connected to the emitters circuit of each power transistor 1TZ. The base resistor 8 is connected to the common point of the collectors of power transistors 1-3. The collector of transistor 9 is connected to the common collector point of power transistors 1-3 The emitter of which is connected to the bases of power transistors. The input resistor 10 is connected between the base of the composite transistor, torus 9 and the control signal source Uvnp, and the base resistor 11 is connected between the same base and the common bus. The power transistors are connected in series with the load 12 to the EIJCT power supply. The protection node contains a transistor 13c with a base divider on resistors 14 and I5i, the collector of transistor 13 and resistor D being connected to a control signal source. and the free end of the resistor 15 to the common bus. Parallel to the resistor 15 including the capacitor 16. The emitter of the transistor 13 is connected to the anode of diode 17 and the cathode of Zener diode 18. The cathode of diode I7 is connected to a common point collector of power transistors. The anode of the Zener diode 18 is connected to the base transistor 19 and the base resistor 20. The collector-emitter junction of the transistor 19 is parallel to the resistor 11. Scha "and works as follows. The voltage drop in the UKII saturated key can be approximated as R, + AUg UKH. Uckn + - where Ujjj is the average value of the voltage at the emitter-collector junction of a saturated power transistor} Hz is the current of the switch; RJ is the resistance value in the emitter circuit; DCD - voltage drop per day p - the number of power transistors in the key. Thus, the value can be used to control the current of the I.C I R key (component) and control the saturated state of the power transis- tion. (component) Since the use of a composite transistor circuit in a transistor switch increases the turn-on time of a transistor switch, there is a need to delay the power protection device from being turned on by the amount of delay of the transistor switch. When applying the wy signaling signal Uynp. to the input of the transistor switch with a time delay t, determined by the circuit design and frequency properties of the power transistors, the transistor switch opens and a current flows through it, determined by the source voltage value. and a load value of 12. Transistor 13 also turns off with a time delay Xj determined by capacitor 16 and resistor 14. T is set equal to or greater than T. At (i Ucrte IK -1, the transistor 19 is closed. At Ucr 13 (i.e. at 1 1, or when the key transistors exit from the national) Zener diode 18 is punctured, the transistor 19 opens and shunts the input of the transistor key, thereby eliminating the possibility of power transistors being tripped. and the transistor 19 remains open until the control signal is applied to the input of the transistor switch.Thus, the proposed device does not have a delay to turn off the power transistors, which increases the reliability of operation. Invention formula A transistor switch containing a power transistor, the base of which through a resistor is connected to the input Pasha and through the collector-1st 1st transition of the protection transistor to the common bus, current limiter in the power circuit, delay element and a threshold element connected through a diode

to the combined terminals of the power transistor and the load, characterized in that, in order to increase the reliability, an additional switch is introduced on the transistor; moreover, the base of the transistor of the additional switch is connected to the output of the delay element, and the collector-emitter circuit is connected between the input bus and the conclusions of the pore element and the diode. Yu

Sources of information taken into account in the examination

1. Author's certificate of the USSR 617841. cl. H 03 K 17/08. 1976.

2. USSR author's certificate number 438114, cl. H 03 K 17/60, 1974 (prototype).

Claims (1)

Claim A transistor switch containing a power transistor, the base of which is connected through a resistor to the input pvc and through the collector-emitter junction of the protection transistor to a common bus, a current limiter in the power circuit, a delay element and a threshold element connected through a diode 5 900 450 to the combined terminals of the power transistor and the load, characterized in that, in order to increase reliability, an additional key is introduced on the transistor, moreover, the base of the transistor of the additional key is connected to the output of the delay element, and the collector-emitter circuit is connected between the input bus and combined with the findings of the pore element and the diode. ίο