SU1325637A1 - Single-cycle direct voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply systems for converting a constant voltage. The goal is to reduce weight and size by reducing the power of the control unit. The device contains a power transistor 1 connected through the primary winding of the transformer 2 to the input power terminals. Transistor 1 is connected to a damping circuit 3.4, the capacitor 4 of which is connected through the discharge transistor 5, the resistor 6 and the diode 7 to the base of the power transistor 1. The energy stored in the capacitor 4 is used in the open state of the power transistor to increase the forward voltage. base current. The discharge transistor 5 opens or closes, thereby supplying a direct base current or disconnecting it, respectively, depending on the state of the power transistor. In the interval between the open-state pulses of the power transistor, the capacitor 4 is charged from the current injected in the dissipation inductance of the transformer 2. A part of the forward base current of the power transistor is provided by the energy stored in the damping circuit and due to the presence of switching overvoltages on the collector of the power transistor 1 . 1 il .. (L soy sd and so

Description

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The invention relates to electrical engineering and can be used in secondary power supply systems for converting a constant voltage.

The purpose of the invention is to reduce the weight and size by reducing the power of the control unit.

The drawing shows a diagram of a one-time constant converter

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The single-phase converter contains a power transistor 1 with a load 2 (power transformer) connected between its collector and the positive output of the power source. The damping capacitor 4 and the emitter of the discharge transistor 5 are connected through the direct-connected damping diode 3 and the emitter of the discharge transistor 5, the collector of which - the connecting resistor 6 and the discharge diode 7 is connected to the base of the transistor 1, the base of the transistor 5. through the resistor 8 is connected to its emitter and through the base; a resistor 9 and a base diode 1 O - with a collector of the power transistor I. The control clock pulses are fed to the input C ,,, and the base of the auxiliary and PD

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11, the emitter of which is connected to the base of the transistor 1, and the collector to the positive terminal of the auxiliary power source E.

The device works as follows.

Consider the established processes of the operation of the circuit, which characterize a non-zero voltage on the damping 40 capacitor 4 by the time of opening the power transistor 1.

Suppose that earlier on the capacitor 4 there was a voltage charge due to the rate of change (decrease) of the collector current of the power transistor.1 when it is locked and the inductance of the dissipation of the primary winding of the power transformer 2. synchronization pulse U. an auxiliary transistor 1 1 is opened, and then transistor -1. This leads to a decrease in yi on his collector. The capacitor 4, which is charged with a 55-magnitude, starts to discharge through the base-emitter junction of the transistor 5, the resistor 9 and the diode 10 to the open transistor 1. Due to this

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A transistor 5 opens. The discharge capacitor 4 through the resistor 6 and the diode 7 begins to flow into the base g of the power transistor 1, and the forward base current of the latter increases. By this, the base current of transistor 1 is increased, which makes it possible to reduce the current drawn from the control circuit at the input during a positive pulse.

After the termination of a positive pulse and the arrival of a negative pulse Uj. (Y transistors 1 and 1 1

15 are locked. The voltage across the collector of transistor 1 increases, charging the damping capacitor 4, and after the arrival of the pulse b (. "" The processes are repeated,

20 In order for transistor 5 not to open when the voltage on the damping capacitor 4 exceeds the voltage on the collector of transistor 1. (after setting the switching

25 processes at its locking), the ratio of resistors 9 must be such that from this difference in voltage the voltage drop across resistor 8 is not sufficient to open the transistor of resistor 5.

In the proposed scheme, in contrast to the known one, the discharge transistor is controlled not from the control circuit, but directly from the power transistor.

og pa, while not consuming power from the control unit, which reduces its weight and size.

Claims (1)

Invention Formula A single-voltage DC-DC converter containing a power transistor connected by an emitter to the first input terminal of the transmitter, a collector through the primary winding of the power transformer, a second input terminal of the converter, and a base connected to the output of the control unit, a protective chain connected in parallel to the power transistor and consisting of a series-connected, first diode and a capacitor, the diode's output being connected to the collector of the power transistor, and the discharge transistor, which is a capacitor eat that with In order to reduce the mass and dimensions by reducing the power of the control unit, three resistors and two diodes are introduced, the power and the discharge transistors are selected 31325637 wounds with different types of conductivity, is connected to the base of the power transistor emitter of the discharge transistor, and the base is sequentially connected to the diode junction point the connected second resistor and the third capacitor protective circuit, the number of diode connected to the collector power The lecturer is connected through a series-connected transistor and through a third resistor first resistor and a second diode to its emitter.