SU410370A1 - - Google Patents

Description

one

Known regulators, for example, for DC stabilizers, containing a power transistor, an additional transistor included in the main circuit of the power transistor, a positive feedback circuit including a current transformer, and a control unit.

However, in known devices, an additional transistor located in the control circuit of the power transistor switches the power much more than the power loss of the control power of the power transistor.

In practice, this drawback often lies in the impossibility of selecting among the existing types of transistors at certain values of the supply voltage a pair of transistors consisting of a power transistor and an additional transistor.

The purpose of the invention is to reduce the switching power of the additional transistor and ultimately reduce it to the power control of the power transistor.

This is achieved in that the secondary winding of the current transformer through the auxiliary transistor is connected in parallel to the emitter – power transistor base, the emitter of the additional transistor is connected to the power base, and the power emitter and base of the additional transistors are connected to the output of the control unit.

2

The drawing shows an electrical circuit diagram of the device.

To unlock, power transistor 1 plus control signal is applied to base of additional transistor 2.

The minimum current from the control unit 3 is equal to / XX of the winding 4 of the current transformer 5, where / XX is the no-load current.

The voltage of the locking signal must be greater than the desaturation voltage of the winding 4.

For the operation of the circuit with a very large porosity, a dissipation diode 6 is placed in the collector circuit of the additional transistor. In this case, the locking signal does not necessarily exceed the saturation of the winding 4.

The saturation of the core of the current transformer is possibly doubled. Either the core is made with a gap, or a forced desaturation over any additional winding. Protection against breakdowns of the additional transistor at the first moment after it is locked (the power transistor is still open) is accomplished by shunting the winding of the current transformer with a diode or a zener diode in the forward direction, and the level of shunting voltage is greater than the operating voltage . In general, core saturation and

3

Overvoltage protection is produced in the same way as the current transistor circuit with current feedback.

The proposed current positive feedback transistor control device can be used, for example, in constant voltage regulators used in static converters for supplying stabilized voltage control circuits. Such a circuit has advantages over other transistor control circuits with positive current feedback.

This is due to the possibility of the operation of a circuit with a variable duty cycle of an open socket of a power transistor and a great simplicity of the circuit. The second is especially important for low power stabilizers of a pap (10-50 W).

Subject invention

A regulator, for example, for DC stabilizers, comprising a power transistor, an auxiliary transistor included in the base circuit of the power transistor, a positive feedback circuit including a current transformer and a control unit, characterized in that in order to reduce the control power and increase reliability, the secondary winding of the current transformer through the additional transistor is connected in parallel to the transition emitter - base of the power transistor, and the emitter of the additional transistor is connected with the base of the power, and the emitter of the power and the base of the additional transistors are connected to the output of the control unit.

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