SU1750047A1 - Magnetic and resistor switch - Google Patents

Abstract

The invention relates to a pulse technique and can be used as a high-speed magnetic transistor switch with current equalization of transistors connected in parallel. The purpose of the invention is to increase the speed and reliability by ensuring the accuracy of the current leveling. The magnet-transistor switch contains the current transformer 1 with the first and second primary windings 2-1 and 2-2, the load circuit bus 3 for the power transistors 4, 5, the secondary winding 6 of the transformer 1, the magnetic conductor 7 of which is made closed with a middle hole. The secondary winding 6 is located on the magnetic core 7, through which the built-in magnetic fluxes of the pair of windings 2-1 and 2-2 pass. Features of the magnetic core 7 and the corresponding connection of the primary windings allow to ensure the accuracy of the alignment of currents, which at high speed determines increased reliability. 1 il. fe

Description

The invention relates to a pulse technique and can be used in contactless switching equipment as high-speed magneto-transistor switches with equalization of the currents of several parallel-connected transistors.

The purpose of the invention is to increase speed and reliability by ensuring the accuracy of current equalization.

The drawing shows a circuit diagram of the proposed device.

The device contains a current transformer 1 with the first and second primary windings 2-1 and 2-2, respectively, the combined outputs of which are connected to the bus 3 of the load circuit, two power transistors 4 and 5, the secondary winding 6 of the current transformer 1. The magnetic core 7 of the transformer 1 current is made closed with a middle hole. The bases of the power transistors 4 and 5 are connected to the control bus 8 through the corresponding resistors 9 and 10, and the emitters are connected to the common bus 11 of the power supply. The secondary (leveling) winding 6 is located on the magnetic core 7, through which the opposing magnetic fluxes of the pair of primary windings 2-1 and 2-2 pass.

The device works as follows.

When the control signal arrives on the device bus 8, the process of turning on the transistor switch begins. In this case, one of the transistors, for example, transistor 4, is faster, and the current in its power circuit appears earlier than in the power circuit of the other transistor. This current, flowing through the winding 2-1 of the current transformer 1, causes the appearance of magnetic flux in the magnetic core 7. This varying magnetic flux causes the current in the secondary equalizing winding 6 to appear in such a direction that the opening speed of transistor 4 decreases and . Thus, the secondary equalization winding 6 causes the redistribution of currents to the control terminals of the transistors (or changes the potentials at the control terminals of the transistors). In the case of using bipolar transistors, the voltage applied to the secondary leveling winding 6 is a fraction of a volt and is determined by the difference in voltage between the shifted base-emitter junction. As a result, the magnetizing inductance can be significantly reduced. In the open state of the transistors occurs

also balancing their currents. Moreover, if transistors with the same allowable gok are used, the windings 2-1 and 2-2 have the same number of turns. Winding 6

may have a different number of turns from windings 2-1 and 2-2.

It should also be noted that in such a key it is possible to use transistors with different permissible currents. Wherein

The number of turns of the windings 2-1 and 2-2 should be inversely proportional to the permissible current of the transistor in the power circuit of which it is connected. In this case, it becomes possible to use a higher-frequency device as one of the transistors, but with a lower permissible current device, which accelerates the on and off times of the entire key as a whole. The operation of the key in this variant is nothing

differs from the previously described, except that the currents are equal in their relative value to the maximum allowable current for this transistor. Now consider the process of turning off the key. When the gate control signal arrives at the bus 8, the process of turning off the fastest transistor begins. However, a decrease in the current in the power circuit of this transistor causes a current in the secondary equalizing winding 6 to appear in such a direction that the process of turning off this switch slows down. another transistor. Thus, during the turn-off process, the dynamic alignment of the currents of the power circuits of the transistors is maintained.

Operation transistor key

with the alignment of the currents N of parallel-connected transistors is no different from that described.

But for the organization of normal operation in this case, the shape of the magnetic circuit

the current transformer must be such that the secondary leveling windings of the current transformer cover only part of the magnetic circuit. along which the opposite magnetic fluxes of the pair of primary windings included in the power circuits of the transistors pass.

Claims (1)

The invention of the magnet-transistor switch containing two power transistors whose emitters are connected to a common power supply bus, the collector of the first power transistor is connected to the first terminal of the first power transistor through the corresponding first winding of the current transformer. connected to the second primary winding, swarm the output of the second primary winding sub-secondary winding of the current transformer to the collector of the second transistor by the first output is connected to the base of the primary of the primary windings of the power transistor, distinguishing - to the load circuit bus that, in order to increase the speed of the 5-rd winding of the current transformer of the connection and reliability due to the provision of a single voltage with the base of the second power leveling current, a two transistor is inserted, and each resistor is switched on stories and magnitoprovodtransformato-between the tire and the corresponding control current pa closed base is formed, the Auto-stvuyuschego power transistor.