SU1034024A1 - Dc voltage semiconductor stabilizer - Google Patents

Abstract

l. SEMICONDUCTOR CONSTANT VOLTAGE STABILIZER containing a source of reference voltage, a unit for comparing the output stabilized voltage with a reference voltage. a control transistor connected in series to the power bus, a feedback amplifier consisting of at least two sequences. but connected amplification stages, the output stage of which is made on a transistor, have an academic conductivity opposite to that of the regulating transistor, and the previous one, the amplification stage is made on a transistor having the same conductivity as the control transistor, characterized in that stability of the output voltage and the stability of the threshold current protection operation, it introduced a current generator, the findings of which are connected to the emitters of the output and pre-output transistors the amplifier cascades are coupled and shunted by a zener diode. 2, the Stabilizer according to claim 1, characterized in that, in order to increase its reliability in operation, a starting circuit is inserted into it, consisting (L. of a resistor and a start button, the connectors of which are connected to the terminals of the resistor, and a resistor connects the collector of the pre-output cascade of the feedback amplifier with the base of the transistor of the output cascade of the feedback amplifier., from 4 oo .4

Description

The invention relates to an electrical system, in particular, to systems for regulating electrical circuits.  A compensating constant voltage regulator is known that contains a regulating element in series (a regulating transistor connected in series with a load to a power source, controlled through a feedback amplifier by a mismatch signal obtained from a comparison of the output voltage (voltage across a load with a reference til .  The disadvantage of this stabilizer is low reliability due to:. destruction of the regulating transistor during current overloads or short circuits (short-circuit at the output of the stabilizer.  The closest in technical essence to the present invention is a semiconductor constant voltage stabilizer containing a source of reference voltage, an output comparison unit. a stabilizing voltage with a reference regulating transistor connected in series to the power bus, a feedback amplifier consisting of at least two consecutive amplification junction boxes, the output stage of which is made on a transistor having a conductivity opposite to that of the regulating transistor, and you the gain driving stage is made of a transistor having a conductivity of the same type as the control transistor 2.  However, the known stabilizer has a strong dependence of the load current limiting threshold on the transistor mode of the output and pre-output cascades of the SD, as well as on the temperature of these transistors and the control transistor; - the stabilizer has a low stabilization factor for the load current, which is obtained from this stabilizer due to a change in the value of the reference voltage.  caused by shunting the power supply with the open transistor of the output stage of the SOS when it enters the saturation mode until the protection trips; complexity, almost impossibility to change the range of load currents due to the lack of paths, effective change of the threshold current of protection operation.  The purpose of the invention is to increase the stability of the output voltage and the stability of the threshold current triggered by the protection.  The goal is achieved by the fact that in a semiconductor voltage stabilizer containing a source of reference voltage, a unit for comparing the output stabilized voltage with a reference voltage regulating transistor connected in series to the power bus, a feedback amplifier at least consisting of. , - of two series-connected amplification stages, the output k-ascad of which is made on a transistor having a conductivity opposite to that of the regulating transistor, and the one that precedes the output stage of the amplification is made on. a transistor having a conductivity of the same type as the regulating transistor, a current generator, the terminals of which are connected, is inputted to the emitters of the output and pre-output transistors of the feedback amplification and shunters: the zener diode.  In addition, in order to increase its reliability in operation, a starting circuit is inserted in it consisting of a resistor and a starting button, the opening of which is i. connected to the terminals of the resistor, and the resistor connects the collector of the transistor of the pre-output stage of the feedback amplifier with the base of the transistor of the output stage of the feedback amplifier.  FIG. 1 shows a stabilizer circuit; in fig. 2 is the same in another embodiment of the stabilizer (with the same distinctive features as the stabilizer in FIG. ) in FIG. 3 is a diagram of the last two (output and pre-exit) stages of the feedback amplifier of the FBL stabilizer, which will explain the essence of the invention {this scheme is common to the two types of stabilizers shown in FIG. 1 and 2); in fig.  4 shows the characteristics of the circuit in FIG. 3; the characteristic of the zener that shunts the output of the current generator and the load characteristic of the output stage transistor at different load resistances, as well as the output characteristic of the gbix circuit. f (in) for three different values of load resistor; in fig. 5 - performance characteristics of circuit stabilizers. which are shown in FIG. 1 and 2: the dependence of the output voltage of the stabilizer on the magnitude of the input signal with an open feedback circuit for different values of the load resistor, as well as the load characteristic of the stabilizer (3n).  Voltage stabilizer (Fig. l contains a regulating (compound or single) transistor 1, connected according to the scheme. with a common emitter (the OE / collector of which is connected to the negative terminal of the power supply source Ep, and the emitter to the common point of an additional two-pole source. 2 with one of the findings load.  And with a common point of the feedback amplifier, the source of the reference voltage Ujjn performed on the Zener diode and the ballast resistor 3, the Feedback Amplifier (SLD /, performed in series with the following cascades; the input cascade on a differential DC amplifier LUPT ) 4 types of integrated DCF K1T401A CB), pre-exit and output cascades on transistors S and b, opposite to each other conductor types, moreover, the conductivity of transistor 5 of the pre-exit stage is the same type as the conductivity of the regulating transient Stora 1.  T) the anzistor b is connected according to the scheme with OE, the collector er through a resistor 7 is connected to the base of the regulating transistor 1, and the emitter is connected to the output terminal of the current generator on the transistor 8 and the output of the zener diode 9, which shunts the output of the current generator.  Transistor 5 is switched on according to the scheme with an OE, the collector of which is connected through a resistor 10, shunted by the break contacts of button 11, to the base of transistor 6, and the emitter is connected to the positive terminal of an additional source with bias across the zener diode 12 included in the forward direction. direction.  UFT 4 is powered from an additional bipolar source E. -tCg ® ® stabilizing circuits on zener diodes and resistors 13 and 14 for negative polarity of supply voltage from source Ej and 15 and 16 - for positive polarity of supply voltage from source The device contains a feedback circuit and a comparison of the output voltage supporting resistors 17 and 18; resistor 17 is connected to a voltage source and resistor 18 connected to a common point of load resistor 19 and a positive power output and; power supply point E To the input of the control device 4, the error voltage e / the output voltage of the UL with traction voltage Ug.  The output voltage of the stabilizer is determined by the expression K Op Ri K where K, - the gain of the feedback amplifier, -.  UH is the output voltage of the stabilizer; Upn is the voltage of the reference source at the zener diode 2, the current generator is made of a transistor 8, a zener diode 20, a current-loading resistor 21 and a ballast resistor 22.  The collector of transistor 8 (in the output port - OUTPUT of the current generator) is connected to the Zener diode 9 (shunting the output of the current generator) and to the emitter of the transistor b of the output stage of the VOS. .  An additional power source, EjCo, with a midpoint, which is connected to the emitter of the regulating transistor 1 and the common point of the SIL, provides power to the SOS, the current generator on the transistor 8, and the source of the reference voltage to the Zener diode 2.  Stabilizer in stabilization mode, t. e.  at permissible load currents, it also works like a normal compensating stabilizer with a sequential regulating element: when the output voltage of the stabilizer U deviates from the nominal value, the error signal figx is generated by comparing the output voltage with the reference voltage UQ, which is amplified. or a feedback loop on the UFT and. the transistors 5 and b are fed to the input of the control transistor 1 and so changes its mode.  (or opens more. or more closes j, that the output voltage of the Stabilizer is reduced to the nominal value.  As the load increases, the output voltage of the stabilizer decreases at the first moment, and in order to bring it to its nominal value when working through the feedback circuit, the control transistor 1 opens, because it must pass a larger load current through itself, respectively, and the transistors b and 5 are opened and the pre-output stages of VOS, With an increase in load and, accordingly, the output current to the threshold value defined by the expression.  7 „RT   where E is the maximum threshold value of the load current, at which I the stabilizer is still in the stabilization mode; JP is the current value generated by the current generator on.  the transistor 8, supplying the output and pre-ESC cascades; p is the coefficient of the gain of the regulating transistor current when it is turned on according to the common emitter circuit, the transistor 6 of the output stage of the VOS enters the saturation mode and cannot already amplify the error signal with a further increase in the load.  Through the transistor b passes the maximum current equal to the current of the transistor 8, and enters the base of the regulating transistor 1.  The voltage of the collector of the transistor b is close to the value of the voltage on the Zener diode 8 (differs by the value of the saturation voltage of the transistor 6J.  With a further increase in the load, the output voltage of the stabilizer decreases, the voltage of the VC mismatch signal input to the AOC input increases, and the amplified ASM must go to the input (base) of the control transistor 1 in order to open it even more.  But this does not occur, since the transistor b of the output stage of the FBM is in saturation mode, and only the transistor 5 of the pre-output stage of the FBM is opened even more.  The transistor 5, when opened, begins to shunt the output of the transistor 8 and part of the current of the current generator until now fully passing through the transistor 6, begins to pass through the transistor 5.  Current. through the transistor 6 decreases, respectively, the base current of the regulating transistor 1 decreases; -1 starts to close, the output voltage of the stabilizer decreases even more, the voltage of the error signal increases, is amplified by the amplifier, and the transistor 5 of the output stage of the ASD opens up more, shunt output current stabilizer.  The current through the transistor 5 increases, and accordingly, the current through the transistor 6 decreases even more, the control transistor 1 closes even more, which leads to a further decrease in the output voltage and so on. d.  There is an avalanche process; the control transistor 1 is locked, the output voltage of the stabilizer is reduced to a value. close to zero, the stabilizer goes to steady state — automatically, turns off.  The effect of automatic shutdown without side effects (for example, shorting the output of an additional power supply E-, Sdbedet exist in the stabilizer only if the pre-output and output stages of the SOS are performed on transistors of the opposite type of conductivity, and transistor / and the power of these transistors is provided by a current generator.  This part of the stabilizer circuit is presented separately in FIG. This also explains the essence of the invention.  The output characteristic of this circuit, 0x (), the output voltage versus input voltage at various load values 19 of the output stage is shown in. When the input voltage increases from zero to a value at which the output transistor 6 goes into saturation, the output voltage also increases to values of I and or output voltages at R With a further increase in the input voltage and AUr, the transistor of the 5th oh of the OL amplifier gain stage opens up more and shifts the load of the output stage of the gain transistor b which is in saturated mode. and, the output voltage begins to decrease.  Finally, the input voltage Ug reaches such a value that the transistor 5 of the pre-output amplifier enters the ENVIRONMENT mode and completely short-circuits (shunts) the common transistor 6 load to the common point, as a result of which the output voltage of the load becomes close to zero.  As a result, in this circuit, with a constant increase in the input voltage Ugjj, the output voltage first rises, reaches its maximum value and then again, decreases to zero.  The output characteristic of the stabilizer in FIG. 1 having a feedback amplifier as indicated in FIG. In the scheme, with an open feedback circuit, it has the same appearance as the output characteristic for the circuit in FIG. H.  The output characteristic of the stabilizer at different values of the load resistance and as a function of the voltage of the DCF 4. (voltage mismatch) EK is represented in FIG. 3 left.  On the same graph, a characteristic of the feedback is constructed, determined by the expression (. } The output characteristic intersects with direct feedback at three points A, B W B.  The intersection point A determines the value of the output voltage of the stabilizer at a given load of 19 and the value of the error voltage Bgx at the input of the DCF 4 when the stabilizer is in stabilization mode / the intersection point B determines the condition of the stabilizer in the Off mode when self-protection is triggered; the intersection point B (the unstable state of the stabilizer) determines the value of the critical error voltage, de for a given load value: when the stabilizer is turned on with the load connected, if the error voltage is lower than the value ABgjj. The stabilizer will tend to enter stabilization mode (point A on chart J, if the error mismatch is greater than 46 r, then stabilizer will tend to enter Off mode (point B on chart) t. e.  Immediately the stabilizer self-defense worked.   load resistance 19 (graph of FIG. 5) is critical,. so only one steady state point remains to the stabilizer; the stabilizer point is in the Off mode.  This shows that with an increase in the load, the stabilizer is above the critical value (a decrease in the load resistance / 19 below the value Rf j, the stabilizer protection operates cstMO and it will only be in the Off mode.  According to the output characteristics of the stabilizer U, f (egx) and the feedback characteristic (U ;; on the right of FIG. 5, the load characteristic of the stabilizer is constructed. The load current NSR -NPOR corresponding to the load resistance R is critical; when it reaches its value, the self-defense of the stabilizer is triggered, and the output current of the stabilizer, as well as the voltage at the output of the stabilizer, decreases to values close to zero. , made according to the scheme (FIG. 1, is high, usually the same order of magnitude, which determines the stability value of the output voltage; conventional compensatory stabil  congestion, since it is mainly determined by the stability of the voltage of the reference source 2 and the drift of the input stage of the ASD cascade (drift of the DCF 4 J, the coefficient of stabilization of the output voltage with respect to the load current is increased by increasing the allowable value of the feedback amplifier, and accordingly , the output resistance of the stabilizer is reduced.  The output resistance of the stabilizer is inversely proportional to the gain of the SAL.  The stability of the stabilizer is also great due to its inherent effect of the sag “protection against overcurrent and short circuit at the output.  The value of the threshold current of self-defense is strictly determined by the value of the current generator,. feeding the output and the pre-exit cascades of the SIL, which also increases the reliability of the stabilizer.  The threshold current is triggered.  self-defense can be easily adjusted by changing the current of the current generator on the transistor 8.  When the stabilizer operates on load, depending on the magnitude of the de-strang-eliminating factors (voltage of the supply voltage of the current source to the load, the power dissipates at the control transistor, the temperature pa of the control transistor also changes accordingly.  In addition, it is necessary to take into account the change in ambient temperature, also leading to a change in temperature of the control transistor 1.  A change in the temperature of the control transistor leads to a change in its characteristics of the gain of the current fbf-leakage current, and so on. d.  which, in turn, leads to a change in the threshold current response of self-defense, since the threshold current triggered is determined by the product of generator current 3 and the gain p of control transistor 1 n f Ti-rTemperature instability of the trigger current can be reduced if instead of current supply a resistor 21 in the current generator, turn on a thermistor with a positive temperature coefficient of resistance and install it on a control transistor radiator to ensure change the threshold current response to temperature.  The efficiency of the stabilizer is increased due to the fact that the load current sensor and the load current resistor are excluded from the stabilizer power circuit, which reduces the minimum voltage between the load and the power source and, accordingly, increases efficiency The adjusting stabilizer is proportional to the ratio of the output voltage of the stabilizer to the voltage of the power supply source.  As can be seen from the characteristics of the stabilizer shown in FIG. 5, the self-defense stabilizer has two stable states (therefore, it is analogous to a trigger J.  The first steady state is the mode of stabilizing or adjusting the output voltage to its nominal value, and the second is the Off mode when the voltage at the output of the stabilizer is close to zero.  When you turn a hundred. setting the equalization of any of the two indicated modes, if the stabilizer load is less than the critical value.  Therefore, after switching on the stabilizer, it must still be entered into the stabilization mode of the output voltage.  There are several ways to enter the stabilizer into the stabilization mode, of which two are practically used: shunting the resistance of the regulating transistor with a small resistor or connecting through a resistor to the base of the regulating transistor of a power supply voltage source.  With such methods of starting, the action of the stabilizer self-propagating is eliminated, the currents through the connected load and through the regulating transistor are allowed above the trigger current, therefore, if the causes of the overload are not detected and it is not eliminated, either the regulator transistor of the stabilizer or connected load, or both.  In addition, when the stabilizer is started up through the regulating port; the passage through the passage, the starting charging currents of the parallel-connected capacitors of the stabilizer and the load to the nominal voltage at the stabilizer output.  These inrush currents transcend the trigger current and contribute to the formation and development of microdefects in the transitions of the regulating transistor, which leads to the destruction of the regulating transistor and a decrease in the reliability of the stabilizer as a whole.  Hence the need to start up in such a way that BJU currents could never occur in the stabilizer power circuit.  threshold current values.  To do this, it is sufficient at the time of the start of the stabilizer to exclude in it the possibility of the occurrence of positive feedback; in the stabilizer (FIG. 1) it is possible to exclude positive feedback if the transistor 5 of the pre-output cascade of the VOS is put in such a mode that it does not bypass the current generator.  For this purpose, it is sufficient between the collector of the transistor 5 of the pre-output stage of the VOS circuit and the base of the transistor 6 of the output stage of the VOS circuit to turn on the resistor 10, which in the stabilization mode will be short-circuited with the break contacts of the stabilizer start button 11.  A stabilizer with self-defense, the scheme of which is shown in FIG. 1 is not uniquely constructed by introducing the one shown in FIG. 3 devices: a two-stage amplifier with transistors of the opposite conductivity type, powered by a current generator, the output of which is shunted by a zener diode.  FIG. 2 shows another variant of the stabilizer circuit having the same characteristics as the stabilizer in FIG. one.  A stabilizer circuit of which is shown in FIG. 2 comprises a control transistor 1 connected in series with the load to the output from the local power source.  The collector of the regulating transistor 1 is connected to the load and the emitter is connected to the positive terminal of the power source -.  : neither; feedback amplifier containing the following stages of amplification: input cascade — DIFT 4 differential on transistors, pre-output cascade on transistor 5 and output cascade on transistor b, current generator On transistor b with current carrying circuit, resistor 21, zener diode 20 and ballast resistor 22.  The output of the current generator (collector of the transistor 8) is shunted by the Zener diode 9 and connected to the emitter of the transistor b of the output stage of the SOS; the source of the reference voltage and, performed on the Zener diode 2 and the current generator on the transistor 23, the Zener diode 24 and the resistors 25 and 26.  The power of the feedback amplifier, the current generator on the transistor 8 of the voltage source on Zener diode 2 and the current generator on the transistor 23 is powered by the voltage of the power supply source.  The stabilizer according to the scheme in FIG. 2 is similar to the stabilizer in FIG. one.  The stabilizer is protected against overcurrent by saturating the transistor b of the output stage and switching to automatic stabilizer mode is ensured by entering into the saturation mode of the transistor 5 of the output stage at which the current generator at transistor 8 shunts to the potential stabilizer bus: a power source Eop connected to the emitter of the control transistor 1.  Stabilizers. have the same characteristics and parameters, except that in the stabilizer in FIG. 2, the stability of the output voltage across the input voltage (the voltage of the power supply) is slightly reduced due to the influence of the change in the voltage of the power supply on the input stage of the VOS; Differential UFT 4 on transistors.  The stabilizer in FIG. H does not have an additional power source, which is an advantage when building stabilizers, fixed connections of the power source and load.  The stabilizer in FIG. 1 is convenient for building power supplies with adjustable output voltage stabilization (laboratory or programmable test power supply).  In the stabilizers according to the scheme in FIG. 1, the output voltage can be varied over a wide range: the control circuit, including the VOS and the ION, does not impose any limitations on the output coupling, the limits are determined by the permissible power dissipation and the voltage across the control transistor.

In the stabilizers according to the scheme in Fig. 2, for a specifically made stabilizer, the output voltage of the stabilization is constant, since the voltage variation of the power source is allowed only within strictly limited limits: restrictions are imposed both by the regulating transistor and by elements of the stabilizer control circuit: ION and URS.

The stabilizer according to the circuits of FIGS. 1 and 2 is easily performed on different stabilization voltages and load currents and can be standardized, separated by characteristics and parameters. In addition, the stabilizers according to the proposed schemes can be manufactured in an integrated design.

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Claims (2)

-1. A DC SEMICONDUCTOR STABILIZER, comprising a reference voltage source, a stabilized output voltage reference comparing unit, a regulating transistor connected in series to the power bus, a feedback amplifier consisting of at least two consecutive but connected amplification stages, the output stage of which is made on a transistor having a conductivity opposite to that of the regulating transistor, and the previous output stage of amplification is performed on the transistor having conductivity of the same type as the control transistor, characterized in that, in order to increase the stability of the output voltage and the stability of the threshold protection current, a current generator is introduced into it, the outputs of which are connected to the emitters of the output and pre-output transistors of the reverse amplifier communications and are shunted by a zener diode. 2. The stabilizer according to claim 1, characterized in that, in order to increase its reliability in operation, a start-up circuit is made into it, consisting of a resistor and a start button, the opening contacts of which are connected to the terminals of the resistor, and the resistor connects the collector of the transistor of the amplifier pre-output stage feedback from the base of the transistor of the output stage of the feedback amplifier. . 'ah ... 1da.4D24_.