SU770425A1 - Stabilized semiconductor converter - Google Patents

Description

Mainly copyright certificate

No. 399033 describes a semiconductor stabilized converter containing a frequency-controlled inverter with a master oscillator made according to the multivibrator circuit on two transistors with an average tap of the transformer primary winding connected between the collectors of these transistors; a regulating unit of reactive elements connected in series with the inverter output and having a maximum impedance at the lower frequency and a minimum impedance at the upper frequency of the inverter-output rectifier with a smoothing filter and a voltage measuring element connected between

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the output of the converter and the measuring input of the master oscillator of the inverter, the prototype of the master oscillator of the inverter, are made according to the circuit of a multivibrator with magnetic feedback (Royer’s generator). The frequency of the master oscillator is controlled by changing the voltage applied to its measuring input from the output of the feedback amplifier of the voltage measuring body (changing the frequency is directly proportional to the change in this voltage). One terminal of the measuring input of the master oscillator here is the midpoint of the primary winding of the multivibrator transformer, and the second terminal is the connection point of the emitters of both transistors of the multivibrator with a common converter power supply bus. In accordance with the characteristic of the frequency response of the regulating unit of reactive elements used in the converters in question, the voltage change at the output of the feedback amplifier (at the input of the Rører multivibrator) must be opposite in sign to the voltage change at the input of the amplifier (at the converter output).

The specified construction of the prototype circuit causes the need to make fundamental changes to it each time with respect to the specified polarities and the values of the input and output voltages of the designed converter. For example, in a simpler case, when the polarities of the input and output voltages of the converter according to the prototype circuit are the same, all transistors of the feedback amplifier of the voltage measuring body can be switched on using a common emitter circuit, and the collector power supply of the amplifier can be taken either from the input , or from the output of the converter (when turned on, the voltage is supplied, of course, from the input). It should be borne in mind that if the input voltage ί is much higher than the output voltage. (down converter) powering the feedback amplifier from the converter output can provide some reduction in energy consumption for regulation and facilitate the task of protecting the converter from short circuits in the load.

In another, equally probable case. tea, when the polarity of the input and you

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the input voltage of the converter according to the prototype scheme is different, there is a need to make certain changes in the scheme, because in this case it is almost impossible without introducing an additional constant-voltage converter (input or output) to a constant, to provide power to the feedback amplifier and the master generator when switched off - from the input, and in normal operating mode - from the output of the converter "If the collector power is supplied only from the input, then it is necessary to modify the amplifier circuit Able so that it can work with the input signal, the polarity of which is opposite to the polarity of the collector supply voltage.

Another - the disadvantage of the prototype is a significant additional energy consumption for regulation, also due to its circuit-constructive implementation. Basically, this energy is consumed by the output stage of the feedback amplifier, the supply voltage and the collector current of which are much higher, respectively, of the input voltage and current of the multivibrator of the master oscillator, fed from the output of the feedback amplifier. .

The first objective of the present invention is to provide the possibility of using the same type of optimal circuit with various combinations of polarities and values of the input and output voltages of the converter.

The second objective of the invention is to reduce the energy consumption for regulation "

Both goals are achieved by the fact that in a semiconductor stabilized envelope, containing: • frequency-controlled! an inverter with a master oscillator made according to the scheme of a multivibrator on two transistors with an average tap of the primary winding of a transformer connected between the collectors of these transistors, connected in series with the output of the inverter regulating unit of reactive elements, having a maximum impedance at the lower frequency and min., the minimum impedance at the top inverter frequency; output rectifier with a smoothing filter; measuring voltage organ included inter 770425

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the converter output and measuring input of the inverter master oscillator, is new, that the supply terminals of the inverter master oscillator, made according to the magnetic multivibrator circuit with resistive collector-base connections, are connected to the converter input terminals via a controlled key and the output terminals of the converter through a diode connected In the forward direction and through a stabilizing diode-resistive chain, and the measuring terminals of the master oscillator are connected to the voltage measuring body via a reg a switching transistor opposite in type of conduction of the transistor of the master oscillator, the base of the regulating transistor is connected to the midpoint of the resistive divider of the voltage measuring organ, the collector is connected to the measuring terminal connected to the base resistors of the master oscillator and (the emitter is connected to the measuring 1 terminal connected to the emitters of both 'transistors master oscillator.

FIG. 1 shows a schematic diagram of a stabilized semiconductor converter with a minus polarity of the input and plus polarity of the output voltage of the converter.

FIG. Figures 2–4 show simplified schematic diagrams of modifications of this ToT converter, corresponding to;

in fig. 2 - negative polarities of input and output voltages;

in fig. 3 ~ positive polarity of the input and negative polarity of the output voltage;

in fig. 4 - positive polarities of input and output voltages,

in fig. 5 shows the modification of the proposed scheme with reference to the low-voltage converter.

In all the schemes presented, it is assumed that the input voltage significantly exceeds the output voltage of the converter.

The semiconductor stabilized converter (Fig. 1) contains a frequency-controlled inverter 1 with a master oscillator 2; regulating unit 3 of reactive elements connected in series with the output of inverter 1 with master oscillator 2; the control unit 3 reactive elements connected in series with the output of the inverter 1 (the primary winding 4 of the power transformer 5 of the inverter); output rectifier 6 with a smoothing filter (in Fig. 1 - choke 7 and capacitor 8); and a voltage measuring unit 9 connected between the output 10 of the converter and the measuring input ·

, 0 house 11 of the master oscillator 2. The master oscillator 2 of inverter 1 is made according to the scheme of multivibrator 12 on transistors 13 and 14, with an average tap 15 of the primary winding of the transformer 1b connected between collectors of transistors 13 and 14. The multivibrator 12 is made according to the circuit with resistive collector -base connections. The collector of each transistor of the multi-20 vibrator 12 is connected to the base of the other transistor through a resistor (resistors 17 and 18, respectively), and the bases of both transistors are connected via resistors (resistors 19 and 20 respectively) to the first terminal 21 of the measuring input 11 of the master oscillator 2. Transistor emitters 13 and 14 are connected to the second terminal 22, and through a common emitter resistor

30 23 - to the first terminal 21 of the measuring input 11 of the master oscillator 2. The middle point 15 of the transformer 1b is connected to the input 24 of the converter through a disconnecting key element 25, controlled from the output 10 of the converter,

35 and to output 10 through the diode 26 in the forward direction (in Fig. 1, the cathode of diode 2b is connected to the grounded negative output terminal of the converter).

F. The voltage measuring body 9 consists of: a series-connected zener diode 27 and a quenching resistor 28 connected to the output terminals 29 and 30 of the converter; resistive divider 31 (resistors 32 and 33),

⁴⁵ connected to the same terminals 29 and 30; and the regulating transistor 34 with the type of conductivity opposite to the type of conductivity of the transistors 13 and 14 of the multivibrator 12. The base of the regulating transistor 34 is connected to the midpoint 35 of the resistive divider 31; the collector of the transistor 34 is connected to the first terminal 21 of the measuring input 11 of the master oscillator 2 and to

55 of the electrode of the Zener diode 27 connected to the quenching resistor 28 (in Fig. 1 - to the cathode of the Zener diode 27); The emitter of transistor 34 is connected through 770425

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cut "resistor 36 to the second terminal 22

, the measuring input 11 of the master oscillator 2, to which the emitters of the transistors 13 and 14 of the multivibrator 12 are connected.

The diagrams of FIG. 2, 3, 4 are almost identical to the scheme of FIG. 1. Only the direction of turning on the diode 26 varies, as well as the conduction types of the 13th transistors.

14 multivibrator 12 and regulating

• transistor 34, depending on the polarities of the input and output voltages of the corresponding modifications of the converter according to the proposed invention.

In the diagrams ..fig. 1,2,3,4, which include: <downconverters, in series with key element 25, a resistor 37 is switched on to equalize the collector supply voltages of the multivibrator 12 from the input and output of the converter supplied to the midpoint 15 of transformer 1b “Stands in in this connection, it should be noted that understanding converters are most widely used as secondary power supplies of equipment such as electronic PBXs, supplied with a voltage of 60 V, 3 of a common station DC source.

On schemafig. 1-4 common tire ι.

The 3θ of the converter, to which its input and output terminals are connected, is connected to the housing (grounded). ·

The scheme of the proposed converter _L (Fig. 1-4) is as follows. - '· way. When the input voltage is turned on (for example, a toggle switch 39), the power supply circuit of the multivibrator 12, the master oscillator 2 from the converter input through the open (closed) key element 25 is created, and the multivibrator begins to generate oscillations of approximately rectangular shape. In the converter with bipolar input / and output (FIG. 1 ifig. 3), the collector power supply current of the multivibrator 12 is closed directly to the common bus 39 of the zener diode 27 in the forward direction directly, and in the converter with one polar input and output (Fig. 2 and Fig. 4) - inconsistent with the capacitor 8 smoothing filter. The oscillations generated by the oscillator master oscillator 2, lead

. Inverter 1 is activated, and its output voltage, rectified by rectifier b, is fed to output 10 of the converter.

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8 the transient voltage at the output 10- (at the capacitor 8 of the smoothing filter) increases to the value at which the stabilization mode of the zener diode 27 is reached, and the key element 25 locks (opens) simultaneously. Starting from this moment, the collector power of the multivibrator 12 of the master oscillator 2 produced from the output of the converter by the stabilized voltage through the diode 26 in the forward direction. ' In this case, the role of a key element can be performed, for example, by the opening contact of an electromagnetic relay, the winding of which is connected to the output 10 of the converter.

“At the stage of switching on the circuit from Zener diode 27 and quenching resistor 28 provides a more stable transition from unsteady to quasi-steady state operation of the device. Under certain conditions, for example, a sufficiently large capacitance value of the smoothing filter capacitor 8, the circuit from Zener diode 27 and resistor 28 may be absent, and The clamp 21 of the measuring input 11 of the master oscillator 2 can be directly connected to the corresponding output terminal of the converter = In this case, the power of the collector circuit of the master oscillator in the quasi-steady state, its operation will be carried out directly by the stabilized output voltage of the converter.

Due to the fact that the voltage of the collector power supply of the multivibrator 12 of the master oscillator 2 is stable during operation, the necessary regulation of the frequency of generation of the multivibrator is provided only by the output of the measuring voltage 9 to the measuring input 11 of the master oscillator 2. This effect is due to the change in the collector current of the regulating transistor 34 depending on the change in the potential of its base. The latter, for its part, is directly dependent on the magnitude of the output the voltage of the converter (the voltage transfer ratio from the output 10 of the converter to the base of the transistor 34 is determined by the division factor. resistive divider 31). The limit value directly depends on the values of the collector current of the transistor 34

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the magnetizing current of the transformer 16 of the multivibrator 12, and hence the duration of the half-period of self-oscillations of the multivibrator. Thus, with an increase in the output voltage of the converter and an increase in the collector current of transistor 34 caused by it, the period of self-oscillations of the multivibrator 12 increases and the frequency decreases. By reducing the output voltage of the converter, the frequency of self-oscillations of the multivibrator 12 (master oscillator 2 of inverter 1) increases accordingly. This dependence of the frequency of the master oscillator 2 on changes in the output voltage of the converter allows for automatic adjustment of the output of the inverter necessary to stabilize the output voltage of the converter. For this, the working range of adjustment of the frequency of the master oscillator 2 must be set within the working section by the frequency of the characteristic of the regulating unit 3 reactive elements.

3 of the proposed converter of FIG. 1-4) the upper and lower thresholds of generation of the multivibrator 12 of the master oscillator 2 (frequency control range of inverter 1) are determined by the release of the resistance values of resistors 23 and 36 "A change in the control potential based on the control transistor 34 causes the required change in the frequency of the master oscillator 2 to those until the transistor 34 is in one of two limiting states: the saturation mode or the locked mode. In the first case, the equivalent resistance in the emitter circuit of the multivibrator 12 is formed parallel to a connection of resistors 23

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and 36; the limit value of the collector current of the transistors 13 and 14 is the maximum, and the frequency of the master oscillator 2 - the minimum. On the contrary, in the locked state of the transistor 34, the limiting value of the collector current of transistors 13 and 14 becomes minimal (only one resistor 23 remains in the emitter circuit), and the frequency of the master oscillator 2 is maximum. Thus, the required limits of the frequency control of the inverter 1 in the working area of the characteristics of the unit 3 of reactive elements are provided.

Due to the relatively narrow relative frequency change, the converter’s adjustment characteristic can be considered as approximately linear.

In the case of using the proposed converter to obtain very low output voltages (less than 5 ~ 6 V), it may present a certain difficulty to ensure the necessary mode of the master oscillator 2 when it is powered from the output 10 of the converter according to the scheme of FIG. 1-4. For such low-voltage converters, it is proposed to use a series-connected zener diode 27 and a quenching resistor 28 to be connected to the output 10 of the converter in series with an additional boost voltage amplifier 40 connected to the auxiliary output of inverter 1 (for example, the winding 41 of the power transformer 5), as shown in FIG. 5. It should be noted that in the diagrams of FIG. 1-5 it is possible to use the key element 25 at the same time and to give an alarm signal (by introducing an additional contact into it).

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Claims (1)

SEMI-CONDUCTOR STABILIZED CONVERTER according to the author's certificate 399 '399033, characterized in that, with the purpose of unifying the structure of the device for different polarities and values of the input and output voltages while increasing the efficiency of the control circuit that supplies the inverter master oscillator designed according to the magnetic circuit multivibrator , with resistive collector-base connections, are connected to the output terminals of the converter through a controlled key and to the output terminals of the converter through a diode connected in the forward direction and through a stabilizing diode-resistive chain, and the measuring terminals of the master oscillator are connected to the voltage measuring unit through an adjusting a transistor opposite in conductivity type to the transistors of the master oscillator, with the base of the regulating transistor connected to the midpoint of the resistive divider measuring Voltage collector, the collector is connected to the measuring terminal connected to the base resistors of the master oscillator, and the emitter is connected to the measuring terminal connected to the emitters of both transistors of the master oscillator. (Ζ) WITH . The proposed semiconductor stabilized converter is intended for use in power supply devices for various radio-electronic equipment, in particular, as a secondary, power source (VIN) of control complexes of electronic automatic telephone exchanges.