Pulse voltage stabilizer

Abstract

FIELD: electrical engineering.SUBSTANCE: invention relates in particular to the field of secondary power supply sources for electrical and electronic equipment, and can be used in the design and development of pulse voltage stabilizers for various purposes. The pulse voltage stabilizer contains a series key regulating transistor, an LCD filter, a Schmitt trigger containing input and output transistors, as well as the necessary resistors, a DC amplifier on an operational amplifier, a bipolar auxiliary power source on Zener diodes, a resistor divider of the output voltage, a reference voltage source and a bipolar auxiliary power source on Zener diodes, the common point of which is connected to the emitter of the key regulating transistor, the base of the key regulating transistor is connected to the collector of the output transistor of the Schmitt trigger through a matching resistor, in parallel to which an accelerating capacitor is connected. The inverting input of the operational amplifier is connected to the midpoint of the output voltage resistor divider, the non-inverting input of the operational amplifier is connected to the reference voltage source, and the output of the operational amplifier is connected to the base of the Schmitt trigger input transistor through its first base resistor.EFFECT: simplification of the stabilizer circuit, reduction in the volume and weight of the elements, and increase in efficiency.1 cl, 2 dwg

Description

[0001] The invention relates to the field of electrical engineering, in particular to the field of secondary power supply sources for electrical and electronic equipment, and can be used in the design and development of pulse voltage stabilizers for various purposes.

[0002] There are two types of pulse voltage stabilizers [1-4]: stabilizers with two-position regulation (relay) and stabilizers with pulse-width regulation. Stabilizers of the first type [1, 2] are simpler and contain a key regulation element, an LCD filter, a DC amplifier, a reference voltage source, and an output voltage divider. Stabilizers of the second type [3, 4] are more complex and contain a large number of units and components. In addition to the elements included in relay stabilizers, they contain a matching transistor, a pulse-width modulator, a master oscillator, and a comparator.

[0003] Both types of stabilizers have their advantages and disadvantages.

[0004] The main drawback of relay voltage stabilizers is the dependence of the switching frequency of the control element on the supply voltage, load current, and other destabilizing factors. As this frequency decreases, the smoothing coefficient of the reactive filter decreases accordingly. Consequently, in some cases, and under certain parameters, relay voltage stabilizers have a comparatively large volume and weight of reactive elements. However, such stabilizers have higher efficiency, as switching power losses are lower than in stabilizers of the second type.

[0005] The second type of stabilizers, with a high switching frequency and a low specified level of output voltage ripple, have a relatively small volume and weight of filter elements, however, they have large switching losses and, consequently, large dimensions of the heat-dissipating radiator and lower efficiency.

[0006] The technical characteristics of any device depend on its input and output parameters and electrical circuit.

[0007] The choice of the stabilizer type depends on the specified input and output parameters: supply voltage and its change range, output voltage, load current, output voltage ripple level, etc.

[0008] For low specified output voltage ripple, it is advisable to use pulse stabilizers of the second type, and if it is necessary to ensure higher efficiency, stabilizers of the first type.

[0009] When the output voltage ripple level is high and acceptable, relay stabilizers are preferable because they have higher efficiency and volumetric mass characteristics comparable to the second type of stabilizer.

[0010] The development of new, more advanced pulse voltage stabilizer circuits with improved volumetric, mass, and energy characteristics is an important and pressing technical task.

[0011] The closest technical solution to the proposed one, which can be taken as a prototype, is the relay-based switching voltage regulator described in [2], which contains a key regulator element based on transistors of different conductivity types, a matching transistor, an LCD filter, a DC amplifier based on an operational amplifier, a resistive output voltage divider, and a reference voltage source. The inverting input of the operational amplifier is connected to the midpoint of the output voltage divider, the non-inverting input of the operational amplifier is connected to the reference voltage source, and the output of the operational amplifier is connected to the base of the matching transistor. A disadvantage of the prototype is the large switching power losses in the transistors of the regulator element, caused by the non-optimal switching mode of the matching transistor.

[0012] The invention solves the problem of reducing power losses during switching of the control transistor and increasing the efficiency of the stabilizer, as well as reducing the volume and weight of its elements by reducing the size of the heat-dissipating radiator of the key control transistor.

[0013] To achieve the technical result, a Schmitt trigger is introduced into the control circuit of the proposed pulse voltage stabilizer, connected between the base of the regulating transistor and the output of the operational amplifier, as well as a bipolar auxiliary power source on zener diodes.

[0014] What is new in the invention is the use of a bistable relaxation circuit with positive feedback (Schmitt trigger) in the stabilizer control circuit, which ensures a reduction in the duration of switching transient processes and, as a result, a reduction in power losses in the stabilizer elements.

[0015] Based on the above, it can be concluded that the proposed device allows for a positive result.

[0016] The invention is new, since when analyzing available sources of information, no analogs with a similar set of essential features were found.

[0017] The invention is industrially applicable, since it can be used in the design and development of pulse voltage stabilizers for various purposes.

[0018] The electrical circuit diagram of the proposed pulse voltage stabilizer is shown in Fig. 1.

[0019] The pulse voltage stabilizer contains a simple or compound regulating transistor 1 connected to the positive output bus, an LCD filter consisting of a filter choke 2, an output capacitor 3 and a reverse diode 4, a Schmitt trigger containing an input 5 and output 6 transistors, the first 7 and second 8 collector resistors, the first 9 and second 10 base resistors, as well as a DC amplifier on an operational amplifier 11, an auxiliary power source on zener diodes 12 and 13, the common point of which is connected to the emitter of the regulating transistor 1, a resistor divider of the output voltage 14 and a reference voltage source 15. The base of the key regulating transistor 1 is connected to the collector of the output transistor 6 of the Schmitt trigger through a matching resistor 16, in parallel to which an accelerating capacitor 17 is connected.The inverting input of operational amplifier 11 is connected to the midpoint of the resistor divider of output voltage 14, the non-inverting input of operational amplifier 11 is connected to the reference voltage source 15, and the output of operational amplifier 11 is connected to the base of input transistor 5 of the Schmitt trigger through its first base resistor 9.

[0020] The proposed switching voltage regulator operates as follows. The stabilizer's operation in steady-state mode with a continuous filter inductor current is considered.

[0021] The time diagrams of currents and voltages on the stabilizer elements are shown in Fig. 2, where the following designations are adopted: U П - supply voltage (input voltage); U ВСП - voltage of auxiliary power source; u кэ , ΔU кэ - instantaneous value of the collector-emitter voltage of the regulating transistor and the voltage drop across it in saturation mode; ΔU д - voltage drop across the diode; uф - voltage at the filter input; i к - collector current of the key control transistor; i др - filter choke current; u н , U н - instantaneous and average value of voltage on the stabilizer load (output voltage); I н - average value of load current; t - current time; T - switching period; i и - pulse time; t п - pause time.

[0022] The output voltage of the stabilizer is regulated by switching the key regulating transistor from the open (closed) state in one part of the switching period to the closed (open) state in the other part of the period.

[0023] When the key control transistor 1 is closed, the voltage at the filter input is (U п -ΔU кэ), the filter choke current increases, the output voltage of the stabilizer is less than its average value and increases, the voltage at the inverting input of the operational amplifier 11 also increases. The voltage at the non-inverting input of the operational amplifier 11 remains unchanged. During this part of the period, the operational amplifier is in the first stable state, in which its output voltage has a maximum value. As a result, the input transistor 5 is open, the output transistor 6 is closed, and the key transistor 1 is opened by the current flowing through the second collector resistor 8 and the matching resistor 16. When the input voltage of the operational amplifier 11 reaches the response level, it switches to another stable state, in which its output voltage has a minimum value. As a result, the input transistor 5 of the Schmitt trigger opens, and its output transistor 6 closes. The key regulating transistor 1 opens at this moment, becauseA positive voltage pulse from the cathode of zener diode 12 is applied to its base circuit. When the key control transistor 1 is open, the voltage at the filter input is equal to ΔU. д , the current of filter 2's inductor and the regulator's output voltage begin to decrease. During this period, operational amplifier 9 is in its second stable state with a minimum output voltage. Input transistor 5 of the Schmitt trigger is off, its output transistor 6 is on, and the key control transistor 1 is off, as a negative voltage pulse from the cathode of zener diode 13 is applied to its base circuit.

[0024] When the stabilizer's output voltage reaches the trigger voltage, the operational amplifier switches back to its first stable state with maximum output voltage. Input transistor 5 of the Schmitt trigger opens, its output transistor 6 closes, and the key control transistor 1 opens.

[0025] The introduction of a Schmitt trigger stabilizer into the circuit, as well as a bipolar auxiliary power supply based on zener diodes, reduces switching power losses in the key regulating transistor 1 during switching, as it is turned on by a positive voltage, and turned off by a negative voltage. These power losses consist of the power losses during turn-on and turn-off. The switching (rollover) process of the circuit occurs abruptly due to the presence of positive feedback in the Schmitt trigger. When the voltage at its input reaches the response threshold, its output voltage abruptly changes from a positive value to a negative one and vice versa. Acceleration capacitor 17, connected parallel to terminating resistor 16, also reduces the duration of transient switching processes and reduces power losses in the key regulating transistor 1.

[0026] In the proposed stabilizer, output voltage ripple smoothing is achieved not only by the reactive filter but also by switching operational amplifier 11 and key regulating transistor 1 at times when the stabilizer's output voltage is close to its maximum or minimum value. Consequently, the amplitude of the stabilizer's output voltage ripple depends not only on the reactive filter parameters but also on the gain of the DC amplifier. Increasing the gain reduces the amplitude of the output voltage ripple. This reduces the inductance, volume, and mass of the inductor and capacitor for a given output voltage ripple amplitude.

[0027] The reactive filter parameters (choke inductance and capacitor capacitance), as well as the input and output parameters of the stabilizer, determine the range of its operating frequency. Optimal values ​​for these stabilizer parameters can be determined during its design and calculation based on the criteria of minimum volume and weight or maximum efficiency for given input and output data.

[0028] Literature

[0029] 1. Aleksandrov F.I., Sivakov A.R. Pulse semiconductor converters and voltage stabilizers. - L.: Energy, 1970, 118 p.

[0030] 2. Aleksenko A.G., Shagurin I.I. Microcircuitry. - M.: Radio and Communications, 1982, pp. 379-381.

[0031] 3. Titze U., Schenk K. Semiconductor circuit technology. - M.: Mir, 1983, pp. 271-275.

[0032] 4. Polikarpov A.G., Sergienko E.F. Single-ended voltage converters in electronic power supply devices. - M.: Radio and Communications, 1989, pp. 9-15, pp. 107-111.

Claims

A pulse voltage stabilizer comprising a series key regulating transistor included in the positive output bus, an LCD filter, a DC amplifier on an operational amplifier, a reference voltage source, a resistor divider of the output voltage and an auxiliary power source, the inverting input of the operational amplifier is connected to the midpoint of the divider of the output voltage, the non-inverting input of the operational amplifier is connected to the reference voltage source, characterized in that a Schmitt trigger is introduced, containing input and output transistors, first and second collector resistors, first and second base resistors, as well as an auxiliary bipolar power source on zener diodes, the base of the input transistor of the Schmitt trigger is connected to the output of the operational amplifier through the first base resistor and to the collector of the output transistor of the Schmitt trigger through the second base resistor,the base of the output transistor is connected to the collector of the input transistor, the collector of the output transistor is connected to the base of the key control transistor through a matching resistor, in parallel to which an accelerating capacitor is connected, the common point of the auxiliary power supply is connected to the emitter of the key control transistor.

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