RU2640745C2 - Blocking-generator for working in autogenerator mode - Google Patents

Abstract

FIELD: electricity.SUBSTANCE: generator contains a key transistor and a transformer, the primary winding of which is connected between the collector of the key transistor and the power source, the secondary winding is connected to the base of the key transistor, and also contains a regulating transistor, the first, the second, the third, and the fourth resistors and a capacitor. The first resistor is connected between the emitter of the key transistor and the common ground, the emitter junction of the regulating transistor is switched on parallel to this resistor, the emitter of the regulating transistor is connected to the common ground, and its base is connected to the emitter of the key transistor, and the collector of the regulating transistor is connected to the base of the key transistor. The end of the secondary winding, which is not connected to the base, is connected through the second resistor to the bias circuit from the voltage divider on the third and the fourth resistors and the capacitor.EFFECT: optimisation of the efficiency ratio and dimensions of the blocking-generator operating in an auto oscillatory mode by reducing the saturation boundary of the magnetic circuit of the transformer.1 dwg

Description

The invention relates to a pulse technique. It can be used to form rectangular pulses with an optimal ratio of efficiency and dimensions of a blocking generator operating in a self-oscillating mode.

Known blocking generator containing a transistor, periodically connecting the primary winding of the transformer to a constant current source with a specific switching frequency, due to the parameters of the bias circuit [1].

The disadvantage of this device is that the transformer core is likely to become saturated, which leads to a sharp increase in current consumption and lower efficiency, or it is necessary to increase the mass of the transformer, i.e. its dimensions.

To increase the efficiency, a blocking generator was proposed containing a pulse transformer, the two primary windings of which are connected to the minus of the power source, its second ends are connected to the collectors of the key transistors through the windings of an additional transformer, the secondary winding of which is connected via the bias circuit to the bases of the key transistors [2] .

However, protection is also not provided here for the transformer core to become saturated, which will then lead to a decrease in efficiency.

This blocking generator is taken as a prototype.

The invention is proposed, the use of which avoids saturation of the core of the transformer.

A schematic diagram of the proposed blocking generator is shown in the drawing.

The proposed blocking generator for operation in the oscillator mode consists of a key transistor 1, the collector of which is connected to the primary winding 3 of the transformer, the second end of which is connected to the plus of the power source, the base of the transistor 1 is connected to the secondary winding of the transformer 4, the second end of which is connected to the bias circuit on resistors 5, 6, 7 and capacitor 8, the emitter of the key transistor 1 is connected directly to the base of the regulating transistor 2 and through the resistor 9 to the minus of the power source, the emitter of the regulating trans ora 2 is connected to a minus power source and regulating the collector of transistor 2 is connected to the base of transistor.

The device works like this.

In the initial state, the capacitor 8 is discharged and the key transistor through the resistor 5 and the winding 4 is closed. The capacitor 8 is charged from the divider on the resistors 6 and 7. When the voltage on the capacitor 8 reaches the opening threshold of the transistor 1, it will open slightly, a part of the supply voltage is applied to the primary winding, which is transformed into the secondary winding of the transformer and applied to the base of the transistor 1 in the opening direction, which leads to an even greater opening of transistor 1. Due to this positive feedback, the process develops avalanche up to the saturation of the key transistor 1, while to the primary ke is applied nearly all of the power supply voltage, which is transformed into the opening 1 voltage transistor. The base current of the open key transistor discharges the capacitor 8. This is a metastable position, due to the applied voltage, the current linearly increases through the winding 3 and transistor 1. This current causes a voltage drop across the resistor 9, and when the current, and accordingly this voltage rises to the threshold opening transistor 2, this transistor, opening, shunts the voltage opening the transistor 1, and the avalanche process of closing the transistor 1 with positive feedback through the transformer begins. The process is then repeated.

Protection against saturation of the transformer magnetic circuit is achieved by the fact that the induction in the core directly depends on the current of the winding, and the current cutoff just below the saturation boundary guarantees the circuit from core saturation and high through currents. Thus, the circuit adjusts the pulse width of the blocking generator so that under any conditions the core accumulates maximum energy in the pulse, but is not saturated.

The technical result of the invention is to optimize the ratio of efficiency and dimensions of a blocking generator operating in a self-oscillating mode.

List of sources used

1. Bobrov I.I. Electronic generators. Perm .: Publishing house Perm. state tech. University, 2008.218 s.

2. Patent RU 2028720.

Claims (1)

A blocking generator for operating in an oscillator mode, comprising a key transistor and a transformer, the primary winding of which is connected between the collector of the key transistor and the power source, the secondary winding is connected to the base of the key transistor, characterized in that it contains a control transistor, first, second, third and fourth resistors and a capacitor, the first resistor being connected between the emitter of the key transistor and the common ground, an emitter junction of the regulatory transformer is connected in parallel with this resistor of the torus, the emitter of the control transistor is connected to the common ground, and its base is connected to the emitter of the key transistor and the collector of the control transistor is connected to the base of the key transistor, the end of the secondary winding, which is not connected to the base, is connected through a second resistor to the bias circuit from the voltage divider to third and fourth resistors and capacitor.

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