RU2340085C1 - Power key on mis transistor - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: power key on MIS transistor containing resistor, transistors of the same conductivity with emitter-to-base junctions bridged by diodes to close. Collector of one transistor is connected to MIS transistor switch. While collector of the other transistor is connected to input of secondary transformer winding, output of which is directly connected to MIS source. Transformer has additional secondary winding. Transistor bases are connected through resistor, and additional secondary winding is connected between transistor cathodes. Input of additional secondary winding is connected to cathode of that transistor, collector of which is connected to MIS transistor switch.

EFFECT: higher reliability and downsizing.

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Description

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

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.

Closest to the proposed technical essence is the power switch on the MOS transistor, containing a resistor, a transformer having a secondary winding and an additional secondary winding, transistors of the same conductivity, the base emitter junctions of which are shunted by diodes in the locking direction, the emitters of the transistors are connected directly, the collector of one of the transistors connected to the gate of the MOS transistor, and the collector of another transistor is connected to the beginning of the secondary winding of the transformer, the end of which is not directly connected to the source of the MOS transistor, and an additional secondary winding is connected between the bases of the transistors through a resistor, and the beginning of the additional secondary winding is connected to the base of that transistor, the collector of which is connected to the beginning of the secondary winding of the transformer (RF patent No. 2262187), which is selected as a prototype .

The disadvantage of the prototype is not sufficiently high reliability and large dimensions, because To create the necessary gate-source control voltage of the MOS transistor, only one secondary winding is used, which has to be performed with a large number of turns, which reduces reliability and increases the size.

The aim of the invention is to increase reliability and reduce the size.

This goal is achieved by the fact that the power switch on the MOS transistor contains a resistor, transistors of the same conductivity, the base-emitter junctions of which are shunted by the diodes in the locking direction, the collector of one of the transistors is connected to the gate of the MOS transistor, and the collector of the other transistor is connected to the beginning of the secondary transformer winding , the end of which is directly connected to the source of the MOS transistor, the transformer has an additional secondary winding, the base of the transistors are connected through a resistor, and tional secondary winding is connected between the emitters of transistors, a beginning of additional secondary winding is connected to the emitter of the transistor, whose collector is connected to the gate of the MISFET.

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 bases of which are connected through a resistor 3, and the base-emitter junctions are shunted by diodes 4 and 5, turned on in the locking direction, a transformer 6 with a primary winding 7, a secondary winding 8 and an additional secondary winding 9 The end of the secondary winding 8 is connected to the source of the MOS transistor 10, and the beginning to the collector of transistor 1. An additional secondary winding 9 is connected between the emitters of transistors 1 and 2, and its beginning is connected to the emitter of the transistor and 2, the collector of which is connected to the gate of the MOS transistor 10.

The device operates as follows.

When applying at the input of the device to the primary winding 7, transformer 6, short positive pulses with high duty cycle on the secondary winding 8 and an additional secondary winding 9, transformer 6, short positive pulses with high duty cycle also appear, a small negative voltage is present between short positive pulses little and can be neglected.

The positive potential from the beginning of the secondary winding 8 and from the beginning of the additional secondary winding 9 is supplied respectively to the collector of transistor 1 and to the circuit of its base through a resistor 3 - base of transistor 1 - emitter of transistor 1 - additional winding 9 - diode 5.

The transistor 1 opens, and the positive potential from the beginning of the secondary winding 8 enters the end of the additional secondary winding 9, their potentials are summed, through the diode 5 they go to the base of the transistor 2 and through its base-collector transition to the gate of the MOS transistor 10, the negative potential c the end of the additional winding 9 through the open transistor 1 goes to the beginning of the secondary winding 8, the potentials of the windings 9 and 8 are summed up and from the end of the winding 8 directly go to the source of the MOS transistor 10, a fast charge of the capacitance occurs thief-source voltage of MOS transistor 10, and it opens. In the pause between short positive pulses, on the secondary winding 8, there is a small negative voltage, but its value is not enough to open the collector-base junction of transistor 1 and diode 4. A small positive voltage will be applied to the base of transistor 2, insufficient to open it along the circuit base of transistor 2 - resistor 3 - diode 4 - additional secondary winding 9 - emitter of transistor 2, and it will be closed, the gate-source capacitance of the MOS transistor 10 remains charged with a positive voltage and, therefore indeed, it remains open.

When short negative pulses with a high duty cycle are applied to the input of the device, similar processes occur, because The potential transfer circuit from the beginning of the secondary winding 8 of the transformer 6 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 MIS transistor closes.

In the proposed device, the number of turns in the secondary winding of the transformer is less than in the prototype by the number of turns in the additional secondary winding of the transformer, which increases reliability and reduces overall dimensions.

A prototype device was assembled on a 1NT251 transistor matrix, 2D522B diodes, 2P769V MOS transistor, TIL2V transformer, 510 ohm resistor.

When controlling pulses with an amplitude of 5 V, τ = 2 μs, Q = 10, the device provided reliable opening and closing of the MIS transistor with a gate-source voltage of ± 8 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)

A power switch on an MOS transistor containing a resistor, transistors of the same conductivity, the base emitter junctions of which are diode-switched by diodes in the locking direction, the collector of one of the transistors is connected to the gate of the MOS transistor, and the collector of the other transistor 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 transformer has an additional secondary winding, characterized in that the base of the transistors are connected through a resistor, and an additional secondary The main winding is connected between the emitters of the transistors, and the beginning of the additional secondary winding is connected to the emitter of the transistor, the collector of which is connected to the gate of the MOS transistor.