RU2775059C1 - Method for constructing a constant voltage stabilizer - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering and can be used in the construction of DC voltage stabilizers. A method for constructing a constant voltage stabilizer is carried out when performing the following operations: generating a feedback voltage; formation of the reference voltage; mismatch voltage formation; mismatch voltage amplification; regulation of the output (stabilized) voltage; autocorrect feedback depth.

EFFECT: expansion of functionality.

1 cl, 7 dwg

Description

State of the art

A known method of constructing a constant voltage stabilizer [Kitaev V.E., Bokunyaev A.A., Kolkanov M.F. "Power supply of communication devices", M.: Svyaz, 1975, p. 187, fig. 8.8.a], [B.I. Artamonov, A.A. Bokunyaev. "Power sources of radio devices", M.: Energoizdat, 1982, p. 145, fig. 5.10.a], [L.F. Zakharov, M.F. Kolkanov. "Power supply of communication devices", M.: GOU "Educational and methodological center for education in railway transport", 2007, p. 128, fig. 5.9.a], which is a closed automatic control system based on a number of operations:

1) formation of feedback voltage;

2) formation of the reference voltage;

3) mismatch voltage formation;

4) amplification of the mismatch voltage;

5) regulation of the output (stabilized) voltage.

A possible implementation of this method is the circuit of a series constant voltage regulator [G.N. Gorbachev, E.E. Chaplygin. "Industrial electronics", M.: Energoatomizdat, 1988, p. 209, fig. 5.11].

The stabilizer circuit contains: a control element based on a pnp -type transistor, which performs the function of regulating the output (stabilized) voltage; a voltage divider based on two resistors, which performs the function of forming a feedback voltage; a voltage divider based on a resistor and a zener diode, which performs the function of generating a reference voltage; a mismatch signal amplifier based on an operational amplifier that performs the functions of generating the mismatch voltage and amplifying the mismatch voltage; load.

The disadvantage of this method and this variant of its implementation are limited functionality due to:

- low stability of the stabilizer as an automatic control system;

– a narrow range of allowable changes in the input voltage;

– low voltage temperature coefficient;

- low stabilization factor.

The closest in technical essence is a method for constructing a DC voltage stabilizer, including operations:

1) formation of feedback voltage;

2) formation of the reference voltage;

3) mismatch voltage formation;

4) amplification of the mismatch voltage;

5) regulation of the output (stabilized) voltage;

6) formation of the control current.

To implement this method, a constant voltage stabilizer was used (patent RU No. 2023287, IPC G05F 1/565).

The DC voltage stabilizer contains: a pnp -type regulating transistor connected between the input and output terminals, the emitter - to the input terminal, the collector - to the output terminal; an operational amplifier of the mismatch signal, the power inputs of which are connected to the input terminals of the stabilizer of the corresponding polarity, and the inverting and non-inverting inputs are connected, respectively, to the outputs of two voltage dividers; the first - consisting of two series-connected resistors; the second - consisting of a series-connected resistor and a zener diode, the cathode of which is connected to the output of the voltage divider; a blocking capacitor, together with the specified voltage dividers and load, connected between the output terminal and the common bus; a pnp -type control transistor, the base of which is connected to the output of the error signal operational amplifier, and the collector is connected to the base of the regulating transistor; a bias resistor connected between the emitter and collector of the regulating transistor; a capacitor and a zener diode connected in parallel between the emitter of the regulating transistor and a common bus, and the zener diode is connected by an anode to a common bus.

The disadvantage of this method and the variant of its implementation are limited functionality due to:

– a narrow range of allowable changes in the input voltage;

– low voltage temperature coefficient;

- low stabilization factor.

Disclosure of invention

The technical result that can be achieved using the present invention is to expand the functionality.

The technical result is achieved by the fact that in the way of constructing a constant voltage stabilizer, based on the following operations: generating a feedback voltage; formation of the reference voltage; mismatch voltage formation; mismatch voltage amplification; regulation of the output (stabilized) voltage, the operation of auto-correction of the feedback depth has been introduced.

Brief description of the drawings

Figure 1 shows a functional diagram of the DC voltage stabilizer.

, напряжении

, сопротивлении нагрузки

.Figure 2 shows a model for studying the parameters of the device circuit at a temperature

, voltage

, load resistance

.

, напряжении

, сопротивлении нагрузки

.Figure 3 shows a model for studying the parameters of the device circuit at a temperature

, voltage

, load resistance

.

, напряжении

, сопротивлении нагрузки

.Figure 4 shows a model for studying the parameters of the device circuit at a temperature

, voltage

, load resistance

.

, напряжении

, сопротивлении нагрузки

.Figure 5 shows a model for studying the parameters of the device circuit at a temperature

, voltage

, load resistance

.

при сопротивлении нагрузки

и температуре

.Figure 6 shows the results of circuit simulation - the dependence of the output voltage of the stabilizer on the change in input voltage

at load resistance

and temperature

.

, при входном напряжении

и сопротивлении нагрузки

.Figure 7 shows the results of circuit simulation - the dependence of the output voltage of the stabilizer on the change in the temperature regime of the device

, at input voltage

and load resistance

.

Implementation of the invention

The essence of the proposed method is to perform the following operations:

1) formation of feedback voltage;

2) formation of the reference voltage;

3) mismatch voltage formation;

4) amplification of the mismatch voltage;

5) regulation of the output (stabilized) voltage;

6) formation of control current;

7) auto-correction of feedback depth.

The device for implementing the method for constructing a constant voltage stabilizer (figure 1) contains: a regulating transistor 1 pnp -type; control MIS transistor 2 with induced channel n -type; operational amplifier 3 error signals; resistor 4 bias; voltage dividers 5 and 6; zener diode 7; blocking capacitor 8; load 9.

The voltage divider 5 contains: resistors 10, 12 and a zener diode 11, and the upper arm is formed by a resistor 10 connected in series and a zener diode 11 connected in the forward direction, and the lower arm is formed by a resistor 12.

The voltage divider 6 contains a resistor 13 and zener diodes 14 and 15, with the upper arm formed by a resistor 13, and the lower arm by series-connected zener diodes 14, 15 connected respectively in the forward and reverse directions.

The bias resistor 4 is connected between the base and the emitter of the regulating transistor 1 pnp -type, connected between the input and output terminals of the stabilizer, the emitter - to the input terminal, the collector - to the output terminal, to which the conclusions of the upper arms of voltage dividers 5 and 6, as well as the first load terminals 9 and blocking capacitor 8; the conclusions of the lower arms of the voltage dividers 5 and 6, as well as the second conclusions of the load 9 and blocking capacitor 8 are connected to a common bus; power inputs of the operational amplifier 3 of the error signal are connected to the input terminals of the stabilizer of the corresponding polarity, and the inverting and non-inverting inputs are connected to the outputs of the voltage dividers 5, 6, respectively; the gate of the control MIS transistor 2 with an induced n -type channel is connected to the output of the operational amplifier 3 of the error signal, the source is connected to the base of the control transistor 1 of the pnp -type and the second output of the bias resistor 4, and the drain through the zener diode 7 connected in the forward direction is connected to the bus.

The device for implementing the method of constructing a DC voltage stabilizer works as follows.

Since the time of establishment and recovery of pn -junctions is finite, at the moment of supply voltage Uin _at the collector of the regulating transistor 1 pnp -type (at the output of the stabilizer), a positive polarity potential jump occurs, not exceeding the breakdown voltage of the zener diode 15, but due to the condition (1 )

, (1)

, (one)

сопротивления резисторов 10, 12, 13,where

resistance resistors 10, 12, 13,

providing excess voltage at the non-inverting input of the operational amplifier 3 error signal relative to the inverting input. As a result, the output voltage of the operational amplifier 3 of the error signal, due to its significant gain, reduces the drain-source resistance of the control MOS transistor 2 with an induced n -type channel. Which in turn provides an increase in the base current, and hence the collector current of the regulating transistor 1 pnp -type.

An abrupt change in the resistance of the drain-source of the control MOS transistor 2 with an induced n -type channel, which means an avalanche-like increase in the collector current of the regulating transistor 1 pnp -type and an uncontrolled jump in the output voltage at the moment the supply voltage is applied, is prevented by the presence of a zener diode 7, which forms an adjustable voltage of the additive volt , which performs the functions of negative current feedback (an increase in drain current leads to an increase in drain voltage, which in turn leads to a decrease in drain current).

An increase in the flowing collector current leads to an increase in the output voltage. And hence the voltage applied to the voltage dividers 5, 6. At the moment the output voltage exceeds the breakdown voltage of the zener diode 15, voltages are formed at the outputs of the voltage dividers 5, 6, which are fed to the inputs of the operational amplifier 3 of the mismatch signal, and taking into account the condition (2)

, (2)

, (2)

опорное (эталонное) напряжение, формируемое цепочкой стабилитронов 14, 15 (напряжение на нижнем плече делителя напряжения 6);where

reference (reference) voltage generated by a chain of zener diodes 14, 15 (voltage on the lower arm of the voltage divider 6);

напряжение падения на резисторе 12 (нижнем плече делителя напряжения 5),

voltage drop across resistor 12 (lower arm of voltage divider 5),

converting the stabilizer to a steady state of operation.

Suppose that during the operation of the device, the value of the input voltage U _in , for example, increases by a certain amount. In this case, the output current of the regulating transistor 1 also increases and, accordingly, the voltage drop across the resistor 12, voltage divider 5, and, consequently, at the inverting input of the operational amplifier 3 of the error signal, while at its non-inverting input the voltage remains unchanged and equal to reference voltage U _op removed from the chain of zener diodes 14, 15. The resulting voltage drop at the inputs of the operational amplifier 3 of the error signal leads to a decrease in the output voltage of the operational amplifier 3 of the error signal, an increase in the drain-source resistance of the control MOS transistor 2 with an induced n -type channel. Which, in turn, leads to a decrease in the base current, and hence the collector current of the regulating transistor 1 pnp -type. A decrease in the output current also leads to a decrease in the output voltage of the stabilizer U _out , thus tending to the previous, initial value.

With a decrease in the input voltage level Uin , the output current of the regulating _transistor 1 also decreases and, accordingly, the voltage drop across the resistor 12, voltage divider 5, and, consequently, at the inverting input of the operational amplifier 3 of the error signal, while at its non-inverting input the voltage remains unchanged and equal to the reference voltage U _op taken from the chain of zener diodes 14, 15. The resulting voltage drop at the inputs of the operational amplifier 3 of the error signal leads to an increase in the output voltage of the operational amplifier 3 of the error signal, a decrease in the drain-source resistance of the control MIS transistor 2 with an induced channel n -type. Which in turn leads to an increase in the base current, and hence the collector current of the regulating transistor 1 pnp -type. An increase in the output current leads to an increase in the output voltage of the stabilizer U _out , thus tending to the previous, initial value.

Under conditions of constant temperature operation of the device, the zener diodes 7, 11, 14 perform the function of an adjustable volt additive, which helps to increase the stability of the output voltage under conditions of instability of both U _in and load resistance 9 ( R _n ), Fig.2÷6.

According to condition (1), taking into account the significant input resistance of the operational amplifier 3 of the error signal, in the steady state operation of the device, relation (3) takes place

, (3)

, (3)

ток делителей напряжения 5, 6;where

voltage divider current 5, 6;

падение напряжения (вольт добавка) на стабилитронах 14, 11.

voltage drop (volt addition) on zener diodes 14, 11.

However, due to the choice of the operating point of the zener diode 14 in the linear section of the current-voltage characteristic, and the zener diode 11 in the non-linear (initial) section of the current-voltage characteristic (according to condition (3)), when changing U _in , R _n , and hence the current dividers 5, 6 from their steady-state values, the relation (4) will take place

(4)

(four)

будет значительно больше, чем степень изменения

, что в свою очередь будет приводить к изменению величины коэффициента обратной связи – увеличению. А значит, и увеличению нагрузочной способности и коэффициента стабилизации.Moreover, as the change U _in , R _n increases from their established values, the degree of change

will be much greater than the degree of change

, which in turn will lead to a change in the value of the feedback coefficient - an increase. This means an increase in load capacity and stabilization coefficient.

The introduction of zener diodes 11, 14 into the structure of the device circuit contributes to the implementation of the operation of auto-correction of the feedback depth.

When operating the device in the temperature range, the zener diodes 7, 11, 14 perform the function of both a volt addition and thermal stabilization. In this case, as zener diodes 7, 11, 14, 15, it is necessary to use zener diodes with an avalanche type of breakdown, characterized by a positive temperature coefficient of voltage (see P. Horowitz, W. Hill. “The Art of Circuitry”, M .: Mir, 1998, p. 351), with reverse connection and a negative coefficient (see Kitaev V.E., Bokunyaev A.A., Kolkanov M.F. “Power supply of communication devices”, M .: Svyaz, 1975, p. 184) when connected directly.

Then the zener diode circuit 14, 15 provides partial compensation of the stabilization voltage coefficients, contributing to the fulfillment of condition (5):

, (5)

, (5)

температурные коэффициенты напряжения стабилитрона 14 и цепи соединения стабилитронов 14, 15.where

temperature coefficients of the voltage of the zener diode 14 and the connection circuit of the zener diodes 14, 15.

And due to condition (6)

, (6)

, (6)

ТКН регулирующего транзистора 1 p-n-p-типа и стабилитрона 11;where

TKN regulating transistor 1 pnp -type and zener diode 11;

ТКН цепи соединения регулирующего транзистора 1 p-n-p-типа и стабилитрона 11,

TKN connection circuit of the regulating transistor 1 pnp -type and zener diode 11,

и 6

будут характеризоваться положительным ТКН с выполнением условия (7)output voltages of voltage dividers 5

and 6

will be characterized by a positive TKN with the fulfillment of condition (7)

, (7)

, (7)

thereby providing with an increase in the temperature regime of the device, a decrease in voltage at the output of the operational amplifier 3 of the mismatch signal. This means that the increase in the resistance of the drain-source of the control MIS transistor 2 with an induced channel n -type. Which in turn leads to a decrease in the base current of the regulating transistor 1 pnp -type and bringing the output voltage of the stabilizer U _out to the original value.

In this case, it should be taken into account that the direct inclusion of the MIS transistor 2 with an induced channel of the n -type zener diode 7 into the drain circuit, due to its negative TCR, along with negative current feedback, additionally generates the formation of negative voltage feedback, which generally contributes to an increase in temperature stability of the output voltage of the device.

, при входном напряжении

и сопротивлении нагрузки

.Figure 3 shows the results of circuit simulation - the dependence of the output voltage of the stabilizer on the change in the temperature regime of the device

, at input voltage

and load resistance

.

Formation of a combined negative feedback in the drain circuit of the MIS transistor 2 with an induced n -type channel due to the introduction of a zener diode 7 into the device circuit, and taking into account the use of MIS transistor 2 as a control transistor, characterized by a normalized TKN (due to the presence of a thermally stable operating point) , contributes to the implementation of the operation of auto-correction of the feedback depth.

In general, the proposed method and variant of its implementation has more functionality in comparison with the prototype.

Claims (1)

A method for stabilizing a constant voltage, including operations: forming a feedback voltage; formation of the reference voltage; mismatch voltage formation; mismatch voltage amplification; regulation of the output stabilized voltage, characterized in that it introduced the operation of auto-correction of the feedback depth, which is implemented by forming a non-linear nature of the mismatch voltage and combined negative feedback, while to form a non-linear characteristic of the mismatch voltage, the specified voltage is formed at the outputs of two output voltage dividers , the upper arm of one of which is formed by a resistor, and the lower arm by two zener diodes connected in series, one of which is connected in the forward direction and the other in the reverse direction, the upper arm of the other voltage divider is formed by a series-connected resistor and a zener diode connected in the forward direction, and the lower arm another resistor, in addition, the combined negative feedback is formed in the drain circuit of the control transistor, the source of which is connected to the base of the control transistor, and the drain is connected through zener diode connected in the forward direction is connected to a common bus.

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