RU2262799C1 - Force key on mis-transistor - Google Patents

Abstract

FIELD: pulse equipment for use in commutation devices.

SUBSTANCE: transformer 5 has additional winding, edge contacts of which are connected to bases of transistors 1 and 2, emitters of which are connected and through resistor 9 are connected to middle point of additional winding, and collector-emitter transfers are linked by diodes 3 and 4 in locking direction. Collector T 1 is connected to start of secondary winding TP 5, end of which is connected to source of MIS-transistor 10, gate of which is connected to collector T 2.

EFFECT: higher reliability, higher efficiency, higher resistance to interference.

1 dwg

Description

The invention relates to a pulse technique and can be applied in various contactless switching devices.

A known power switch containing an isolation transformer, two complementary bipolar transistors, capacitors, resistors and diodes (High-frequency converters on high-power MOS transistors / B.V. Kabelev - ETvA, 1984, issue 15, p. 27, Fig. 5).

However, this switch does not allow switching long pulses.

The closest to the proposed technical essence is the power switch on the MOS transistor, containing a transformer, transistors, resistors and diodes, for two transistors of the same conductivity, a resistor is connected between the bases, the base-emitter junctions are shunted by the resistors, and the collector-emitter junctions are diodes, included in the locking direction, the emitters are connected to the secondary winding of the transformer, and the collectors to the gate-source junction of the MOS transistor (RF patent No. 2152127, Н 03 К 17/567), which is selected as a prototype.

The disadvantages of the prototype are not sufficiently high reliability, efficiency in the control circuit and noise immunity.

The aim of the invention is to increase reliability, efficiency and noise immunity.

This goal is achieved by the fact that an additional winding is introduced into the transformer, the extreme terminals of which are connected to the bases of transistors whose emitters are connected directly, the middle point of the additional winding is connected to the emitter connection point through a resistor, and its beginning is connected to the base of the transistor whose collector is connected to the beginning of the secondary winding of the transformer, the end of which is directly connected to the source of the MOS transistor.

The drawing shows a circuit diagram of a power switch on an MOS transistor.

The power switch on the MOS transistor contains transistors 1 and 2 of the same conductivity, the collector-emitter junctions of which are shunted by diodes 3 and 4 in the locking direction, a transformer 5 with a primary winding 6 and a secondary winding 7, the transformer 5 is made with an additional winding 8, the middle terminal of which through a resistor 9 is connected to the connection point of the emitters of transistors 1 and 2, and the extreme terminals of the additional winding are connected to the bases of transistors 1 and 2, and the beginning of the additional winding 8 is connected to the base of transistor 1, and the end - to the base of transistor 2, the beginning of the secondary winding 7 is connected to the collector of transistor 1, the end is directly to the source of the MOS transistor 10, the gate of which is connected to the collector of transistor 2.

The device operates as follows.

When applying to the input of the device on the primary winding 6 of transformer 5 short positive pulses with high duty cycle on the secondary winding 7 and additional winding 8 of transformer 5, short positive pulses with high duty cycle also appear, the small negative voltage present between the short positive pulses is small, and they can be neglected.

The positive potential from the beginning of winding 7 and the beginning of additional winding 8 enters the collector of transistor 1 and its base, respectively, along the circuit - the base of transistor 1, the beginning of additional winding 8, the middle output of the additional winding 8, resistor 9, emitter of transistor 1. Transistor 1 the positive potential opens from the beginning of the winding 7 through it and the diode 4 enters the gate of the MOS transistor 10, the negative potential from the end of the winding 7 directly goes to the source of the MOS transistor 10, a fast charge of the gate capacitance occurs the source of MOS transistor 10 and it opens.

In the pause between short positive pulses on the secondary winding 7 of transformer 5 there is a small negative voltage and its value is not enough to open the diode 3, a small positive voltage will be applied to the base of transistor 2, insufficient to open it along the circuit - base of transistor 2, end of the additional winding 8 , the middle point of the additional winding 8, the resistor 9, the emitter of the transistor 2 and it will be closed and the gate-source capacitance of the MOS transistor 10 remains charged with a positive voltage and it remains open.

When applying to the input of the device on the primary winding 6 of the transformer 5 short negative pulses with a high duty cycle, similar processes occur, because the potential transfer circuit from the beginning of the winding 7 of the transformer 5 to the gate of the MOS transistor 10 is symmetrical, while the gate-source capacitance of the MOS transistor 10 is recharged - a negative voltage is applied to the gate relative to the source and the MOS transistor 10 is closed.

In the proposed device, two elements (resistors) are less than in the prototype, therefore, its reliability is higher due to the use of fewer elements, the efficiency of the proposed device is greater due to the fact that the base circuits of the transistors are powered from an additional winding 8 with a lower transformation ratio relative to windings 7 and therefore consume less power from the control circuit. The noise immunity of the proposed device is higher due to the fact that the end of the secondary winding 7 of the transformer 5 is connected directly to the source of the MOS transistor 10, the source of which, as a rule, is grounded or connected to the common bus in the executive circuit and the interference currents acting on the secondary winding 7 of the transformer 5 flow down to ground or to a common bus.

A prototype device was assembled on a 1NT251 transistor matrix, 2D522B diodes, 2P762A MOS transistor, TIM 254 transformer.

When controlling pulses with an amplitude of 9 V, τ = 2 μs, Q = 40, the key switched a current of 20 A with a duration of edges of 35 ns, while the current consumption of the circuit forming the control pulses was 0.4 mA at U _pit = 9 V.

Of the patent information materials known to the applicant, no signs were found that are similar to the totality of the features of the claimed object.

Claims (1)

Power switch on an MOS transistor containing transistors of the same conductivity, the collector-emitter junctions of which are shunted by diodes in the blocking direction, the collector of one of the transistors is connected to the gate of the MOS transistor, a transformer, a resistor, characterized in that an additional winding is inserted into the transformer, extreme terminals which are connected to the bases of transistors, the emitters of which are connected directly, to the connection point of the emitters through the resistor is connected the middle point of the additional winding, and its beginning It is connected to the base of the transistor whose collector is connected to the beginning of the secondary winding of the transformer, the end of which is directly connected to the source of the MOS transistor.