SU961133A1 - Pulse-width regulator with current feedback - Google Patents

Description

(54) PULSE-PULSE REGULATOR WITH CURRENT FEEDBACK The invention relates to a pulsed technique and can be used in the construction of constant-voltage regulators with a wide range of variation of -load. A device containing two power transistors, a current transformer with two power, two base, one control windings, two start-up transistors, a control unit and an AC switch of two diodes and two transistors is known. 1. The disadvantage of the device is that the reliability is low due to the occurrence of high-frequency oscillations in the windings of the current transformer at the time of the control winding with an AC switch causing spurious switching on the power transistors. The closest in technical terms to the proposed1 1у is a current-feedback controlled pulse-width modulator containing a current transformer with two power, two base volts, control and start windings, the first and second power transistors, between the bases and the emitters of which include the base windings of the current transformer, the first and second transistors of stall, the first and second diodes, the control unit, the load 2. A disadvantage of the known device is low reliability due to parasitic inclusions of power transistors when the transistors close the control winding. The purpose of the invention is to increase the reliability of the device by eliminating the parasitic inclusions of power transistors. The goal is achieved by the fact that in a pulse-width regulator with a current feedback, containing a current transformer with two power, two basic and control windings, the first and second power transistors, the base and emitters of which are included in the base windings of the current transformer, the first and the second break transistors, the first and second diodes, the control unit, the load, the collectors of the power transistors are connected to the common bus through the load, and the emitters are connected to the power bus through the power windings of the current transformer The emitters of the stall transistors are connected to the power bus, and the bases are connected through resistors to the first output of the control unit, the second output of which is connected to the power bus, between the collectors of the transistor and the power transistors, the cathodes to the latter are connected to the first and second diodes, with anodes which are connected to the control winding of the current transformer and triggering the outputs of the control bdok ..

FIG. 1 shows a diagram of the proposed device; in fig. 2 - timing diagrams for the device operation

The pulse width regulator contains two power transistors 1 and 2, a transformer for current 3 with base 4 and 5, power 6 and 7, and control 8 windings, and the opposite outputs of the corresponding power 6 and 7 and base windings 4 and 5 are connected to . The same electrode electrodes of transistors 1 and 2. Load 9 is connected to the connection point of the collectors of transistors 1 and 2. The cathodes of diodes 10 and 11 are connected to the bases of power transistors 1 and 2, and the stresses of transistors 12 and 13, respectively, are connected to their anodes. control winding 8 and pins skayuschego output 14 of the control unit 15. To the bases of the transistors 12 and 13 stall, through the isolating resistors 16. And 17, and to the emitters of these transistors are connected the outputs of the 18th terminal of the control unit 15. FIG. 2a shows pulses J San of triggering output 14 of control unit 15, and FIG. 2 5 shows the output pulses from the output 18 of the control unit 15.

Pulse width controller works as follows.

 At the moment t-, from the output 14 of the control unit 15, a triggering pulse arrives at the control winding 8 and an electromotive force is induced in the base windings of the current transformer 3. At the transition, the emitter-base of a single power transistor, for example, 1, the EMF has such a polarity that transistor 1 opens. At the same time to

the emitter junction, the base of the transistor 2 is applied to the EMF of the locking polarity and the transistor 2 remains locked. The busbar – winding 6 –– transistor 1 –– load 9 –– common bus circuit begins to flow a current that induces an emf in the windings of a current transformer of such a sign that transistor 1 is kept open and load 9 is connected to a power source. In this state, the circuit is from time t- to t. At this time (the emitter-base transition of transistors 12 and 13 is applied, a blocking voltage is applied and these transistors are locked. At time t from output 18 of control unit 15, a stall pulse Ucp comes in which unlocks transistors 12 and 13. It results in 4 and 6 are connected through transistor 13 by a multi-turn winding 8, current starts to flow through diode 1O, as a result, the base current of transistor 1 decreases and transistor 1 closes. Starting from time 2 to tj, the transistors 1 and 2 are locked and the load is disconnected from the power supply Currently ij, comes trigger pulse to the transistor 2, and it is turned on. Thus, transistors 1 and 2 are turned on alternately and provide a load connection to the power supply, the time off state is determined srsha pulses.

The pulse-width current feedback regulator is simpler in terms of device design and possesses higher reliability than known devices due to the absence of parasitic switching on of power transistors.

Claims (2)

Invention Formula A current feedback feedback pulse width controller containing a current transformer with two power, two base and control windings, the first and second power transistors, between the bases and emitters of which are included the base windings of the current transformer, the first and second transistors of the current, first and second A second diode, a control unit, a load, characterized in that, in order to increase reliability, the collectors of the power transistors are connected to the common length through the load, and the emitter is connected to the bus through the power windings of the current transformer power, the emitters of the stall transistors are connected to the power bus, and the bases are connected through resistors to the first stall output of the control unit, the output of which is connected to the power bus, between the collectors of the stray transistors and the bases of the power transistors, the first and second diodes are connected to the latter, the anodes of which are connected to the control 9 36 winding of the current transformer and the triggering outputs of the control unit. Sources of information taken into account during the examination 1. USSR author's certificate N9 817991, cl. H 03 K 7 / O8, 11.05.79. 2. USSR author's certificate. No. 766000, cl. H 03 K 3/08; 11/15/78. Z / 0 z 12 1B 18 15 FI -G -ff // d V / j P g Fi.g. one i t. I P IG