SU1480057A1 - Single-clock dc converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power sources. The purpose of the invention is to simplify by combining the functions of starting and regulating with a simultaneous increase in efficiency over a wide range of load variations. The converter contains a power switch 1, a current transformer 2, an output transformer 3 with a diode 5 and a capacitor 4. The control circuit is combined with the pulse switching circuit of the power switch and is performed on a blocking generator with a widely varying oscillation frequency, the power circuit of the control transistor 8 the blocking generator is connected to the source of the error signal, for example, between the divider 6 and the source of the reference voltage 12. 3 Cp, f-crystals, 1 sludge.

Description

The invention relates to a conversion technique and can be used in the development of electrolyte sources.

The purpose of the invention is to simplify by combining the functions of start-up and regulation with a simultaneous increase in efficiency in a wide range of load changes, providing an external start-up.

The drawing shows a schematic diagram of a converter.

The converter contains a transistor key element 1, the collector-emitter junction of which is connected to the input terminals through the primary current winding of the current transformer 2 and the primary winding of the output transformer 3. The secondary winding of the output transformer 3 is connected to a half-wave rectifier with a filter capacitor 4, made according to the circuit with a reverse connection of the diode 5., A feedback voltage divider 6 is connected to the output terminals of the rectifier, the output of which is connected through a timing capacitor 7 to the emitter of the control transistor 8 of the blocking generator with transformer 9, the primary winding of which is connected between the collector of the control transistor and the common output of the converter, the base winding between the base of the control ranzistora and output feedback voltage divider and the output winding through diode 10 and resistor 11 is connected to the control transition of the power transistor, which is also connected to the secondary winding 2 of the transformer current. The emitter of the control transistor is connected to the output of the reference voltage source 12 ·;

The device operates as follows.

When applying the reference voltage of the element 12 to a blocking generator made on the control transistor. Re 8, the latter produces short pulses that produce (through the diode 10 and resistor 11) the inclusion of the transistor switch 1. Due to the positive feedback through the current control transformer 2, the switch 1 is blocked in the on state for a time determined by the saturation of the core of this transformer. Thus, the switch periodically changes the state of its conductivity. In this case, a voltage appears on the capacitor 4 and the output of the midpoint of the divider 6. When it increases so that it is equal to the voltage of the reference element 12, the transistor 8 closes and the blocking generator stops working. It will generate the next pulse only after the discharge of the capacitor 4 (due to the flow of current through the divider or the load), when a decrease in voltage at the midpoint of the divider leads to the opening of the transistor 8. Thus, the output voltage is stabilized, and the blocking frequency increases with an increase in the load current -generator.

The implementation of the primary and secondary windings of the transformer of the blocking generator on the core of the current transformer 2 does not change the essence of the processes. In this case, the output winding of the transformer 9 and the elements connected to it can be excluded.

Thus, the introduction of a blocking generator with a widely varying oscillation frequency made it possible to significantly simplify the converter circuit by combining the control and start-up functions in one node and to ensure a converter operating mode in which its own losses (switching losses and switching losses) are reduced proportionally load current (by reducing the switching frequency), which allows for high efficiency in a wide range of load current changes.

Claims (4)

Claim 1. A single-ended DC-voltage converter containing an output transformer, the primary winding of which is connected to the input terminals through the current winding of the current transformer and the collector-emitter junction of the power transistor, the secondary winding of the current transformer is connected to the control junction of the power transistor and the secondary winding of the output transformer is connected to a rectifier with a filter, to the output terminals of which a feedback voltage divider is connected, as well as a control transistor and a support a different element, characterized in that, in order to simplify by combining the start and control functions with a simultaneous increase in efficiency, a self-oscillating blocking generator is introduced, made on the specified control transistor, the base-emitter junction of which is connected between the feedback voltage divider and the reference element. 2. The converter according to claim 1, characterized in that the primary and control windings of the transformer of the blocking generator are located on the magnetic circuit of said current transformer. 3. The converter according to claim 1, characterized in that the primary and control windings of the blocking generator transformer are located on an additional magnetic circuit, while its output winding is connected to the control junction of the power transformer through a diode and a resistor. 4. The converter according to paragraphs. 1-3, characterized in that, in order to ensure external start, the supporting element is connected to the control transition of the transistor of the blocking generator through an additional controlled key.