RU2223596C2 - Power switch built around mis transistor - Google Patents

Abstract

FIELD: pulse engineering; contactless switching devices. SUBSTANCE: power switch built around MIS transistor 9 has transformer with primary winding 2 and secondary winding 3, similar-conductivity transistors 7 and 8 with resistor 6 inserted between their bases. Emitters of transistors 7 and 8 are connected to secondary winding 3 of transformer 1 and collectors, to gate-source junction of MIS transistor 9. Base-emitter junctions of transistors 7 and 8 are shorted out by diodes 4 and 5 in cut-off direction. EFFECT: enhanced reliability. 1 cl, 1 dwg

Description

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

 Known power switch containing a dividing transformer, two complementary bipolar transistors, capacitors, resistors and diodes (UDC 621.314.5: 621.382.32 High-frequency converters on high-power MOS transistors / B.V. Kabelev - ETvA, 1984, issue 15, s .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, between the bases of which a resistor is connected, 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, 2152127, Н 03 К 17/567), which is selected as a prototype .

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

 This goal is achieved by the fact that the base-emitter junctions of the transistors are shunted by the diodes in the locking direction.

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

 The power switch on the MIS transistor contains an isolation transformer 1 with a primary winding 2 and a secondary winding 3, diodes 4, 5, a limiting resistor 6, transistors 7, 8, an MIS transistor 9, diodes 4, 5 are connected in parallel with the base-emitter transistors 7 8 in the locking direction, the limiting resistor 6 is connected between the bases of the transistors 7, 8, the secondary winding 3 of the transformer 1 is connected between the emitters of the transistors 7, 8, the gate-source of the MOS transistor 9 is connected between the collectors of the transistors 7, 8.

 The device operates as follows.

 When short positive pulses with high duty cycle are applied to the input of the device to winding 2 of transformer 1, secondary positive pulses with high duty cycle also appear on the secondary winding 3 of transformer 1, the small negative voltage present between the short positive pulses is small and can be neglected.

 The positive potential from the top winding 3 of the transformer 1 through the diode 4 and the base-collector junction of the transistor 7 goes to the gate of the MOS transistor 9 and through the diode 4 and the resistor 6 to the base-emitter junction of the transistor 8, causing the base current to flow through the circuit - the upper terminal of the winding 3 of the transformer 1, diode 4, resistor 6, the base-emitter junction of the transistor 8, the lower terminal of the winding 3 of the transformer 1, the transistor 8 opens and the negative potential from the lower terminal of the winding 3 of the transformer 1 goes to the source of the MIS-tr anzistor 9, there is a fast charge of the gate-source capacitance of the MOS transistor 9, and it opens, the transistor 7 is closed.

 In the pause between short positive pulses on the secondary winding 3 of transformer 1, there is a small negative voltage, but its value is not enough to open the diode 5 and transistor 7 in the circuit - the lower terminal of the winding 3 of transformer 1, diode 5, resistor 6, base-emitter junction of transistor 7 , the upper terminal of the winding 3 of the transformer 1 and the MOS transistor 9 remains open positive voltage of the charged gate-source capacitance of the MOS transistor 9.

 When applying to the input of the device on the primary winding 2 of the transformer 1 short negative pulses with a high duty cycle, similar processes occur, because the device circuit is symmetrical, while the gate-source capacitance of the MOS transistor 9 is recharged - a negative voltage is applied to the gate-source of the MOS transistor, and it closes.

 In the proposed device, two elements are less than in the prototype, therefore, its reliability is higher due to the use of fewer elements, in addition, the overall dimensions are improved, which is essential when using a large number of keys, especially in on-board space equipment.

 A prototype device was assembled at BTIZ-61, 2T3117A, 2D522B, 2P762A. When controlling pulses of 10 V, τ = 3 μs, Q = 500, the key switched a current of 10 A with a duration of edges of 40 ns, while the current consumption of the circuit forming the control pulses was 1.5 mA at Upit = 5 V.

 Of the patent information materials known to the applicant, no features similar to the distinguishing features of the claimed object were found.

Claims (1)

The power switch on the MOS transistor, containing a transformer, diodes, transistors of the same conductivity, between the bases of which a resistor is connected, emitters are connected to the secondary winding of the transformer, and the collectors are connected to the gate-source junction of the MOS transistor, characterized in that the base-emitter junctions of the transistors are bridged diodes in the locking direction.