SU1654941A1 - Dc converter - Google Patents

Abstract

The invention relates to the field of electrical engineering and can be used in secondary power supply sources. The goal is to increase efficiency. The device contains a startup node 1, a control node 2, the output of which is connected via a complementary pair of transistors 3,4 with a gate of a field MOS transistor 5 connected by a drain to the primary winding of the output transformer 6. At high frequency, the control of the MOS transistor 5 is forced recharge the equivalent drain-source, drain-gate, gate-source capacitances. The connection of the transistor 3 of the complementary pair of transistors 3, 4 through the diode 9 with the drain of the field MIS transistor 5 allows recharging the gate-source capacitance of the field MIS transistor 5 due to the energy stored in the drain-source capacitance .. 1 Il. w Ё

Description

The invention relates to the field of electrical engineering and can be used in the sources of secondary power supply systems of radio engineering, automation and computer technology. .

The aim of the invention is to increase the efficiency of a dc voltage converter by reducing losses in a field-switching transistor.

The drawing shows an electrical circuit of a DC converter.

The DC / DC converter contains a starting node 1, a control node 2, a complementary pair of transistors 3,4, a field MIS transistor 5, an output transformer 6, an additional rectifier 7, a capacitor 8 and a diode 9.

The Converter operates as follows. When the input voltage is connected, the control unit 2 is provided with the supply voltage through the start-up node 1 and starts producing control pulses. At this point in time, the MIS field-effect transistor 5 is locked while the capacitance between the gate and the source is released and the voltage on the drain-source capacitors and the drain gate is equal to the input voltage. When a positive voltage arrives at the base of the transistor 3, it begins to unlock, and the drain-capacitor of the MIS transistor 5 discharges through the diode 9 and the equivalent resistance of the transistor 3 and simultaneously the charge accumulated in the drain-source capacitance charges the gate capacitance source through the same unlocking transistor 3 and diode 9.

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At this point in time, the current flowing through the primary winding of the transformer b is limited by the scattering inductance and is much less than the recharge current of the capacitances of the MIS transistor 5.

As the capacitance of the gate-WTO of the field MIS transistor 5 is unlocked and the voltage across its drain decreases. When the voltage on the drain of the field MOS transistor 5 decreases below the voltage level at the base of the transistor 3, the diode 9 is closed and further charging of the capacitance gate of the field MOS transistor 5 m to maintain the required gate voltage in the open state occurs - DIT on the base-emitter circuit of the transistor 3 from the control node 2,

When the positive voltage is removed from the output of the control unit 2, the transistor 4 is unlocked, recharging the gate-source capacitance l. It locks the MIS transistor 5.

8 further, the converter operation cycle is repeated. In steady state operation, the control unit 2 is powered from the output of the additional rectifier 7, the output of which is shunted by the filter capacitor 8.

Experimental studies of a DC converter have shown that, compared with a device of similar purpose, this converter has a higher efficiency, and the power consumed by the control circuit is reduced 5-10 times (depending on the parameters of the MIS FET 5) by using the energy stored in the equivalent capacitances of the field MOS transistor 5.

Claims (1)

Claims A DC / DC converter containing a startup node connected in series with the control node between the input terminals, an output transformer, the secondary winding of which is connected to the output terminals, the primary winding is connected between the first input terminal and the drain of the MIS transistor, the source of which is connected to the second input terminal, and the gate is connected to the connection point of the emitters of the complementary pair of transistors, the bases of which are connected and connected to the output of the control unit, the point The connection of which with the start node is connected to the first output of the additional rectifier, the output of which is bridged by a capacitor, and the second output is connected to the second input output, to which the collector of the first transistor of the complementary pair is connected, in order to increase efficiency, a diode is connected between the drain of the MOSFET transistor and the collector of the second transistor of the complementary pair, + Ubx & -