Regulation of charging current through the primary winding. Charger with regulation in the primary winding of the transformer. For the "backup power supply" circuit

In stabilizers with PWM, a generator is used as a pulse element, the pulse or pause time of which varies depending on the constant signal arriving at the input of the pulse element from the output of the comparison circuit.

Operating principle of a PWM stabilizer is as follows. DC voltage from the rectifier or battery is supplied to the regulating transistor, and then through the filter to the output of the stabilizer. The output voltage of the stabilizer is compared with the reference voltage, and then the difference signal is applied to the input of a device that converts the direct current signal into pulses of a certain duration, the latter changing in proportion to the difference signal between the reference and measured voltage. From a device that converts direct current into pulses, the signal is sent to a control transistor; the latter periodically switches and the average voltage value at the filter output depends on the ratio between the time the transistor is in the open and closed states (on the pulse width - hence the name of this type of modulation), and the PWM pulse repetition rate is constant. When the voltage at the output of the stabilizer changes, the direct current signal changes, and therefore the width (duration) of the pulse (at a constant period); As a result, the average value of the output voltage returns to its original value.

In stabilizers with PFM When the signal at the output of the pulse element changes, the duration of the pause changes, but the duration of the pulse remains unchanged. Moreover, unlike stabilizers with PWM, the switching frequency of the control transistor depends on changes in the load current and output voltage, and therefore is a changing, non-constant value - hence the name of this type of modulation. The operating principle of such stabilizers is similar to the operating principle of PWM stabilizers. A change in the output voltage of the stabilizer causes a change in the pause, which leads to a change in the pulse frequency and the average value of the output voltage remains unchanged.

Operating principle of relay or two-position stabilizers are somewhat different from the principle of operation of stabilizers with PWM. In relay stabilizers, a trigger is used as a pulse element, which in turn controls a regulating transistor. When a constant voltage is applied to the input of the stabilizer, at the first moment the regulating transistor is open and the voltage at the output of the stabilizer increases, and the signal at the output of the comparison circuit increases accordingly. At a certain value of the output voltage, the signal at the output of the comparison circuit reaches a value at which the trigger is triggered, closing the control transistor. The voltage at the output of the stabilizer begins to decrease, which causes a decrease in the signal at the output of the comparison circuit. At a certain signal value at the output of the comparison circuit, the trigger fires again, opens the control transistor and the voltage at the output of the stabilizer begins to increase; it will increase until the trigger closes the control transistor again, and thus the process repeats.

Change input voltage or load current of the stabilizer will lead to a change in the open state time of the control transistor and to a change in its switching frequency, and the average value of the output voltage will be maintained (with a certain degree of accuracy) unchanged. Thus, as in PFM stabilizers, in relay stabilizers the switching frequency of the control transistor is not constant.

Advantages and disadvantages of the described stabilizers.

1. In principle, output voltage ripple in stabilizers with PWM and PWM may be completely absent, since the pulse element is controlled by the constant component of the control circuit signal; In relay stabilizers, output voltage pulsations must fundamentally take place, since periodic switching of the trigger is possible only when the output voltage periodically changes.

One of the main disadvantages of PWM and PWM stabilizers compared to relay ones is their lower operating speed.

Currently, microcircuits (domestic and imported) are widely represented on the market, which implement a different set of PWM control functions for pulse sources nutrition. Among microcircuits of this type, KR1114EU4 (manufacturer: Kremniy-Marketing JSC, Russia) is quite popular. Its imported analogue is TL494CN (Texas Instrument). In addition, it is produced by a number of companies under different names. For example, (Japan) produces the IR3M02 microcircuit, (Korea) - KA7500, f. Fujitsu (Japan) МВ3759.

The KR1114EU4 (TL494) chip is a PWM controller for a switching power supply operating at a fixed frequency. The structure of the microcircuit is shown in Fig. 1.

Based on this microcircuit, it is possible to develop control circuits for push-pull and single-cycle switching power supplies. The microcircuit implements a full set of PWM control functions: generation reference voltage, amplification of the error signal, formation of a sawtooth voltage, PWM modulation, formation of a 2-cycle output, protection against through currents, etc. Available in a 16-pin package, the pinout is shown in Fig. 2.

The built-in ramp voltage generator requires only two external components to set the frequency - Rt and Ct. The frequency of the generator is determined by the formula:

To turn off the generator remotely, you can foreign key close the RT input (pin 6) to the ION output (pin 14) or short the ST input (pin 5) to the common wire.

The chip has a built-in reference voltage source (Uref = 5.0 V), capable of providing a current flow of up to 10 mA to bias the external components of the circuit. The reference voltage has an error of 5% in the operating temperature range from 0 to +70°C.

The block diagram of a pulsed step-down stabilizer is shown in Fig. 3.

The regulating element RE converts the input DC voltage UBX into a sequence of pulses of a certain duration and frequency, and the smoothing filter (inductor L1 and capacitor C1 converts them again into an output constant voltage. Diode VD1 closes the current circuit through the inductor when the RE is turned off. With the help feedback The control circuit of the control system controls the regulating element in such a way that the desired stability of the output voltage Un is ultimately obtained.

Stabilizers, depending on the stabilization method, can be relay, pulse-frequency modulated (PFM) and pulse-width modulated (PWM). In stabilizers with PWM, the pulse frequency (period) is a constant value, and their duration is inversely proportional to the value of the output voltage. Figure 4 shows pulses with different duty cycles Ks.

PWM stabilizers have the following advantages compared to other types of stabilizers:

the conversion frequency is optimal (from the point of view of efficiency), determined by the internal oscillator of the control circuit and does not depend on any other factors;
the pulsation frequency at the load is a constant value, which is convenient for constructing suppression filters;
It is possible to synchronize the conversion frequencies of an unlimited number of stabilizers, which eliminates the occurrence of beats when several stabilizers are powered from a common primary DC source.

The only thing is that the circuits with PWM differ comparatively complex circuit management. But the development of integrated circuits of the KR1114EU4 type, containing inside most control units with PWM, allows you to significantly simplify pulse stabilizers.

The circuit of a pulsed step-down stabilizer based on KR1114EU4 is shown in Fig. 5.

The maximum input voltage of the stabilizer is 30 V, it is limited by the maximum permissible drain-source voltage of the p-channel field-effect transistor VT1 (RFP60P03). Resistor R3 and capacitor C5 set the frequency of the sawtooth voltage generator, which is determined by formula (1). From the reference voltage source (pin 14) D1, through a resistive divider R6-R7, part of the reference voltage is supplied to the inverting input of the first error amplifier (pin 2). The feedback signal through the divider R8-R9 is fed to the non-inverting input of the first error amplifier (pin 1) of the microcircuit. The output voltage is regulated by resistor R7. Resistor R5 and capacitor C6 carry out frequency correction of the first amplifier.

It should be noted that the independent output drivers of the microcircuit ensure operation of the output stage in both push-pull and single-cycle modes. In the stabilizer, the output driver of the microcircuit is switched on in single-cycle mode. To do this, pin 13 is connected to the common wire. Two output transistors (their collectors are pins 8, 11, emitters are pins 9, 10) are connected according to a common emitter circuit and operate in parallel. In this case, the output frequency is equal to the generator frequency. The output stage of the microcircuit through a resistive divider

R1-R2 controls the regulator regulator element - field-effect transistor VT1. For more stable operation of the stabilizer on the power supply of the microcircuit (pin 12), the LC filter L1-C2-C3 is included. As can be seen from the diagram, when using KR1114EU4 a relatively small number of external elements. It was possible to reduce switching losses and increase the efficiency of the stabilizer thanks to the use of a Schottky diode (VD2) KD2998B (Unp=0.54 V, Uarb=30 V, lpr=30 A, fmax=200 kHz).

To protect the stabilizer from overcurrent, a self-restoring fuse FU1 MF-R400 is used. The operating principle of such fuses is based on the property of sharply increasing their resistance under the influence of a certain current value or temperature environment and automatically restore its properties when these causes are eliminated.

The stabilizer has maximum efficiency (about 90%) at a frequency of 12 kHz, and the efficiency at output power up to 10 W (Uout = 10 V) reaches 93%.

Details and design. Fixed resistors are type S2-ZZN, variable resistors are SP5-3 or SP5-2VA. Capacitors C1 C3, C5-K50-35; C4, C6, C7 -K10-17. Diode VD2 can be replaced with any other Schottky diode with parameters no worse than the above, for example, 20TQ045. The KR1114EU4 chip is replaced by TL494LN or TL494CN. Choke L1 - DM-0.1-80 (0.1 A, 80 µH). Inductor L2 with an inductance of about 220 μH is made on two ring magnetic cores folded together. MP-140 K24x13x6.5 and contains 45 turns of 01.1 mm PETV-2 wire, laid evenly in two layers around the entire perimeter of the ring. Between the layers there are two layers of varnished fabric. LShMS-105-0.06 GOST 2214-78. Self-resetting fuse type MF-RXXX can be selected for each specific case.

The stabilizer is made on a breadboard measuring 55x55 mm. The transistor is installed on a radiator with an area of at least 110 cm2. During installation, it is advisable to separate the common wire of the power part and the common wire of the microcircuit, as well as to minimize the length of the conductors (especially the power part). The stabilizer does not require adjustment if installed correctly.

The total cost of purchased stabilizer radio elements was about $10, and the cost of the VT1 transistor was $3...4. To reduce the cost, instead of the RFP60P03 transistor, you can use the cheaper RFP10P03, but, of course, this will make things worse specifications stabilizer.

The block diagram of a boost-type pulse parallel stabilizer is shown in Fig. 6.

In this stabilizer, the regulating element RE, operating in pulse mode, is connected in parallel with the load Rh. When the RE is open, current from the input source (Ubx) flows through inductor L1, storing energy in it. At the same time, diode VD1 cuts off the load and does not allow capacitor C1 to discharge through the open RE. The current to the load during this period of time comes only from capacitor C1. At the next moment, when the RE is closed, the self-induction emf of inductor L1 is summed with the input voltage, and the energy of the inductor is transferred to the load. In this case, the output voltage will be greater than the input voltage. Unlike the step-down stabilizer (Fig. 1), here the inductor is not a filter element, and the output voltage becomes greater than the input voltage by an amount that is determined by the inductance of the inductor L1 and the duty cycle of the control element RE.

The schematic diagram of a pulse boost stabilizer is shown in Fig. 7.

It uses basically the same electronic components as in the step-down stabilizer circuit (Fig. 5).

Ripple can be reduced by increasing the capacitance of the output filter. For a “softer” start, capacitor C9 is connected between the common wire and the non-inverting input of the first error amplifier (pin 1).

Fixed resistors - S2-ZZN, variable resistors - SP5-3 or SP5-2VA.

Capacitors C1 C3, C5, C6, C9 - K50-35; C4, C7, C8 - K10-17. Transistor VT1 - IRF540 (n-channel field-effect transistor with Uс=100 V, lc=28 A, Rс=0.077 Ohm) - installed on a radiator with an effective surface area of at least 100 cm2. Throttle L2 is the same as in the previous circuit.

It is better to turn on the stabilizer for the first time with a small load (0.1...0.2 A) and a minimum output voltage. Then slowly increase the output voltage and load current to maximum values.

If the step-up and step-down stabilizers operate from the same input voltage Uin, then their conversion frequency can be synchronized. To do this (if the buck stabilizer is the master and the step-up stabilizer is the slave) in the step-up stabilizer you need to remove resistor R3 and capacitor C7, close pins 6 and 14 of the D1 chip, and connect pin 5 of D1 to pin 5 of the D1 chip of the step-down stabilizer.

In a boost-type stabilizer, inductor L2 does not participate in smoothing out the ripple of the output DC voltage, therefore, for high-quality filtering of the output voltage, it is necessary to use filters with sufficient large values L and C. This, accordingly, leads to an increase in the weight and dimensions of the filter and the device as a whole. Therefore, the power density of a step-down stabilizer is greater than that of a step-up stabilizer.

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Currently, microcircuits (domestic and imported) are widely represented on the market, which implement a different set of PWM control functions for switching power supplies. Among microcircuits of this type, KR1114EU4 (manufacturer: Kremniy-Marketing JSC, Russia) is quite popular. Its imported analogue is TL494CN (Texas Instrument). In addition, it is produced by a number of companies under different names. For example, (Japan) produces the IR3M02 microcircuit, (Korea) - KA7500, f. Fujitsu (Japan) МВ3759.

The KR1114EU4 (TL494) chip is a PWM controller for a switching power supply operating at a fixed frequency. The structure of the microcircuit is shown in Fig. 1.

Based on this microcircuit, it is possible to develop control circuits for push-pull and single-cycle switching power supplies. The microcircuit implements a full set of PWM control functions: generation of a reference voltage, amplification of an error signal, generation of a sawtooth voltage, PWM modulation, generation of a 2-cycle output, protection against through currents, etc. It is produced in a 16-pin package, the pinout is shown in Fig. 2.

The built-in ramp voltage generator requires only two external components to set the frequency - Rt and Ct. The frequency of the generator is determined by the formula:

To turn off the generator remotely, you can use an external key to short-circuit the RT input (pin 6) to the ION output (pin 14) or short-circuit the ST input (pin 5) to the common wire.

The block diagram of a pulsed step-down stabilizer is shown in Fig. 3.

The regulating element RE converts the input DC voltage UBX into a sequence of pulses of a certain duration and frequency, and the smoothing filter (choke L1 and capacitor C1 converts them again into an output constant voltage. Diode VD1 closes the current circuit through the inductor when the RE is turned off. Using feedback, the control circuit of the control system controls the regulating element in such a way that the resulting stability of the output voltage Un is obtained.

PWM stabilizers have the following advantages compared to other types of stabilizers:

The conversion frequency is optimal (in terms of efficiency), determined by the internal oscillator of the control circuit and does not depend on any other factors; the pulsation frequency at the load is a constant value, which is convenient for constructing suppression filters; It is possible to synchronize the conversion frequencies of an unlimited number of stabilizers, which eliminates the occurrence of beats when several stabilizers are powered from a common primary DC source.

The only difference is that PWM circuits have a relatively complex control circuit. But the development of integrated circuits of the KR1114EU4 type, containing inside most of the control units with PWM, makes it possible to significantly simplify pulse stabilizers.

The circuit of a pulsed step-down stabilizer based on KR1114EU4 is shown in Fig. 5.

R1-R2 controls the regulator regulator element - field-effect transistor VT1. For more stable operation of the stabilizer on the power supply of the microcircuit (pin 12), the LC filter L1-C2-C3 is included. As can be seen from the diagram, when using KR1114EU4 a relatively small number of external elements is required. It was possible to reduce switching losses and increase the efficiency of the stabilizer thanks to the use of a Schottky diode (VD2) KD2998B (Unp=0.54 V, Uobr=30 V, lpr=30 A, fmax=200 kHz).

To protect the stabilizer from overcurrent, a self-restoring fuse FU1 MF-R400 is used. The operating principle of such fuses is based on the property of sharply increasing their resistance under the influence of a certain current value or ambient temperature and automatically restoring their properties when these causes are eliminated.

The stabilizer has maximum efficiency (about 90%) at a frequency of 12 kHz, and the efficiency at output power up to 10 W (Uout = 10 V) reaches 93%.

The block diagram of a boost-type pulse parallel stabilizer is shown in Fig. 6.

The schematic diagram of a pulse boost stabilizer is shown in Fig. 7.

It uses basically the same electronic components as in the step-down stabilizer circuit (Fig. 5).

Fixed resistors - S2-ZZN, variable resistors - SP5-3 or SP5-2VA.

Capacitors C1 C3, C5, C6, C9 - K50-35; C4, C7, C8 - K10-17. Transistor VT1 - IRF540 (n-channel field-effect transistor with Uсi=100 V, lc=28 A, Rсi=0.077 Ohm) - is installed on a radiator with an effective surface area of at least 100 cm2. Throttle L2 is the same as in the previous circuit.

It is better to turn on the stabilizer for the first time with a small load (0.1...0.2 A) and a minimum output voltage. Then slowly increase the output voltage and load current to maximum values.

In a boost-type stabilizer, inductor L2 does not participate in smoothing out the ripple of the output DC voltage, therefore, for high-quality filtering of the output voltage, it is necessary to use filters with sufficiently large values of L and C. This, accordingly, leads to an increase in the weight and dimensions of the filter and the device as a whole. Therefore, the power density of a step-down stabilizer is greater than that of a step-up stabilizer.

In this article you will learn about:

Each of us uses in our lives a large number of various electrical appliances. A very large number of them require low-voltage power. In other words, they consume electricity, which is not characterized by a voltage of 220 volts, but should have from one to 25 volts.

Of course, special devices are used to supply electricity with such a number of volts. However, the problem does not arise in lowering the voltage, but in maintaining its stable level.

To do this, you can use linear stabilization devices. However, such a solution will be a very cumbersome pleasure. This task will ideally perform any switching voltage stabilizer.

Disassembled pulse stabilizer

If we compare pulse and linear stabilization devices, their main difference lies in the operation of the control element. In the first type of devices, this element works like a key. In other words, it is either in a closed or open state.

The main elements of pulse stabilization devices are regulating and integrating elements. The first ensures the supply and interruption of electrical current. The task of the second is to accumulate electricity and gradually release it to the load.

Operating principle of pulse converters

Operating principle of a pulse stabilizer

The main principle of operation is that when the regulating element is closed, electrical energy is accumulated in the integrating element. This accumulation is observed by increasing voltage. After the control element is switched off, i.e. opens the electricity supply line, the integrating component releases electricity, gradually reducing the voltage. Thanks to this method of operation, the pulse stabilization device does not consume a large amount of energy and can have small dimensions.

The regulating element can be a thyristor, a bipolar transient or a field-effect transistor. Chokes, batteries or capacitors can be used as integrating elements.

Note that pulse stabilization devices can operate in two different ways. The first involves the use of pulse width modulation (PWM). The second is a Schmitt trigger. Both PWM and Schmitt trigger are used to control the switches of the stabilization device.

Stabilizer using PWM

A switching DC voltage stabilizer, which operates on the basis of PWM, in addition to the switch and integrator, contains:

generator;
operational amplifier;
modulator

The operation of the switch directly depends on the input voltage level and the duty cycle of the pulses. The last characteristic is influenced by the frequency of the generator and the capacitance of the integrator. When the switch opens, the process of transferring electricity from the integrator to the load begins.

Schematic diagram of a PWM stabilizer

In this case, the operational amplifier compares the levels of the output voltage and the reference voltage, determines the difference and transmits the required gain to the modulator. This modulator converts the pulses produced by the generator into rectangular pulses.

The final pulses are characterized by the same duty cycle deviation, which is proportional to the difference between the output voltage and the reference voltage. It is these impulses that determine the behavior of the key.

That is, at a certain duty cycle, the switch can close or open. It turns out that main role impulses play in these stabilizers. This is actually where the name of these devices comes from.

Schmitt trigger converter

Those pulse stabilization devices that use a Schmitt trigger no longer have such a large number of components as in the previous type of device. Here the main element is the Schmitt trigger, which includes a comparator. The task of the comparator is to compare the voltage level at the output and its maximum permissible level.

Stabilizer with Schmitt trigger

When the output voltage exceeds its maximum level, the trigger switches to the zero position and opens the key. At this time, the inductor or capacitor is discharged. Of course, the characteristics of the electric current are constantly monitored by the aforementioned comparator.

And then, when the voltage drops below the required level, phase “0” changes to phase “1”. Next, the key is closed, and electricity goes to the integrator.

The advantage of such a pulse voltage stabilizer is that its circuit and design are quite simple. However, it cannot be applied in all cases.

It is worth noting that pulse stabilization devices can only work in certain directions. What we mean here is that they can be either purely downward or purely upward. There are also two more types of such devices, namely inverting and devices that can arbitrarily change the voltage.

Scheme of a reducing pulse stabilization device

In the future, we will consider the circuit of a reducing pulse stabilization device. It consists of:

Regulating transistor or any other type of switch.
Inductors.
Capacitor.
Diode.
Loads.
Control devices.

The unit in which the supply of electricity will be accumulated consists of the coil itself (inductor) and a capacitor.

While the switch (in our case, the transistor) is connected, current flows to the coil and capacitor. The diode is in the closed state. That is, it cannot pass current.

The initial energy is monitored by a control device, which at the right moment turns off the key, that is, puts it in the cut-off state. When the switch is in this state, there is a decrease in the current that passes through the inductor.

Buck pulse stabilizer

In this case, the direction of the voltage in the inductor changes and, as a result, the current receives a voltage, the value of which is the difference between the electromotive force of the self-induction of the coil and the number of volts at the input. At this time, the diode opens and the inductor supplies current to the load through it.

When the supply of electricity is exhausted, the key is connected, the diode is closed and the inductor is charged. That is, everything repeats itself.
A step-up switching voltage stabilizer works in the same way as a step-down voltage regulator. An inverting stabilization device is characterized by a similar operating algorithm. Of course, his work has its differences.

The main difference between a pulse boost device is that its input voltage and coil voltage have the same direction. As a result, they are summed up. In the pulse stabilizer, a choke is first placed, then a transistor and a diode.

In an inverting stabilization device, the direction of the EMF of the self-induction of the coil is the same as in a step-down device. While the switch is connected and the diode closes, the capacitor provides power. Any of these devices can be assembled with your own hands.

Helpful advice: instead of diodes, you can also use switches (thyristor or transistor). However, they must perform operations that are the opposite of the primary key. In other words, when the main key closes, the key should open instead of the diode. And vice versa.

Based on the above-defined structure of voltage stabilizers with pulse regulation, it is possible to determine those features that are considered advantages and which are disadvantages.

Advantages

The advantages of these devices are:

It is quite easy to achieve such stabilization, which is characterized by a very high coefficient.
High level efficiency. Due to the fact that the transistor operates in a switch algorithm, low power dissipation occurs. This dissipation is significantly less than in linear stabilization devices.
The ability to equalize voltage, which at the input can fluctuate over a very wide range. If the current is constant, then this range can be from one to 75 volts. If the current is alternating, then this range can fluctuate between 90-260 volts.
Lack of sensitivity to input voltage frequency and power supply quality.
The final output parameters are quite stable even if very large changes in current occur.
Ripple voltage that comes out of pulse device, is always within the millivolt range and does not depend on the power of the connected electrical appliances or their elements.
The stabilizer always turns on softly. This means that the output current is not characterized by jumps. Although it should be noted that when turned on for the first time, the current surge is high. However, to level out this phenomenon, thermistors are used that have a negative TCR.
Small values of mass and size.

Flaws

If we talk about the disadvantages of these stabilization devices, they lie in the complexity of the device. Due to the large number various components, which can fail quite quickly, and the specific method of operation, the device cannot boast of a high level of reliability.
He constantly faces high voltage. During operation, switching occurs frequently and complex temperature conditions for a diode crystal. This clearly affects the suitability for current rectification.
Frequent switching of switches creates frequency interference. Their number is very large and this is a negative factor.

Helpful advice: to eliminate this shortcoming you need to use special filters.

They are installed both at the entrance and at the exit. In the case when repairs need to be made, they are also accompanied by difficulties. It is worth noting here that a non-specialist will not be able to fix the breakdown.
Repair work can be carried out by someone who is well versed in such current converters and has the required number of skills. In other words, if such a device burns out and its user does not have any knowledge about the features of the device, then it is better to take it to specialized companies for repair.
It is also difficult for non-specialists to configure switching voltage stabilizers, which may include 12 volts or another number of volts.
If a thyristor or any other switch fails, very complex consequences may arise at the output.
The disadvantages include the need to use devices that will compensate for the power factor. Also, some experts note that such stabilization devices are expensive and cannot boast of a large number of models.

Areas of application

But despite this, such stabilizers can be used in many areas. However, they are most used in radio navigation equipment and electronics.

In addition, they are often used for LCD TVs and LCD monitors, power supplies digital systems, as well as for industrial equipment that needs a current with a low number of volts.

Helpful advice: pulse stabilization devices are often used in AC networks. The devices themselves convert such current into direct current even if it is necessary to connect users who need alternating current, then you need to connect an anti-aliasing filter and a rectifier at the input.

It is worth noting that any low-voltage device requires the use of such stabilizers. They can also be used to directly charge various batteries and power high-power LEDs.

Appearance

As noted above, current converters pulse type characterized by small size. Depending on the range of input volts they are designed for, their size and appearance depend.

If they are designed to operate with very low input voltages, they may consist of a small plastic box from which a certain number of wires extend.

Stabilizers, designed for a large number of input volts, are a microcircuit in which all the wires are located and to which all components are connected. You have already learned about them.

The appearance of these stabilization devices also depends on functional purpose. If they provide a regulated (alternating) voltage output, then the resistor divider is placed outside the integrated circuit. In the event that a fixed number of volts comes out of the device, then this divider is already located in the microcircuit itself.

Important Features

When selecting a switching voltage stabilizer that can produce constant 5V or another number of volts, pay attention to a number of characteristics.

The first and most important characteristic are the values of the minimum and maximum voltage that will enter the stabilizer itself. The upper and lower limits of this characteristic have already been noted.

The second important parameter is the most high level current at the output.

The third important characteristic is the nominal output voltage level. In other words, the spectrum of quantities within which it can be found. It is worth noting that many experts claim that the maximum input and output voltages are equal.

However, in reality this is not the case. The reason for this is that the input volts are reduced at the switch transistor. The result is a slightly smaller number of volts at the output. Equality can only occur when the load current is very small. The same applies to minimum values.

An important characteristic of any pulse converter is the accuracy of the output voltage.

Helpful advice: you should pay attention to this indicator when the stabilization device provides an output of a fixed number of volts.

The reason for this is that the resistor is located in the middle of the converter and its exact operation is determined in production. When the number of output volts is adjusted by the user, the accuracy is also adjusted.