Universal automobile converter (converter) "DC/DC".

This is a simple, universal DC/DC converter (converter of one DC voltage to another). Its input voltage can be from 9 to 18 V, with an output voltage of 5-28 volts, which can be changed if necessary within the range of approximately 3 to 50V. The output voltage of this converter can be either less than the input voltage or more.
The power supplied to the load can reach up to 100 W. The average load current of the converter is 2.5-3 amperes (depending on the output voltage, and with an output voltage of, for example, 5 volts, the load current can be 8 amperes or more).
This converter is suitable for various purposes, such as powering laptops, amplifiers, portable TVs and other household appliances from the car’s 12V on-board network, as well as charging mobile phones, USB devices, 24V equipment, etc.
The converter is resistant to overloads and short circuits at the output, since the input and output circuits are not galvanically connected to each other, and for example, failure of a power transistor will not lead to failure of the connected load, and only the voltage will be lost at the output (well, the protective fuse will blow).

Picture 1.
Converter circuit.

The converter is built on the UC3843 chip. Unlike conventional circuits of such converters, here, not a choke, but a transformer is used as an energy-producing element, with a turns ratio of 1:1, and therefore its input and output are galvanically isolated from each other.
The operating frequency of the converter is about 90-95 kHz.
Select the operating voltage of capacitors C8 and C9 depending on the output voltage.
The value of resistor R9 determines the current limiting threshold of the converter. The smaller its value, the greater the limiting current.
Instead of trimming resistor R3, you can install a variable one, and use it to regulate the output voltage, or install a series of constant resistors with fixed output voltage values, and select them with a switch.
To expand the range of output voltages, it is necessary to recalculate the voltage divider R2, R3, R4, so that the voltage at pin 2 of the microcircuit is 2.5 volts at the required output voltage.

Figure 2.
Transformer.

The transformer core is used from computer power supplies AT, ATX, on which the DGS (group stabilization choke) is wound. The coloring core is yellow-white, any suitable cores can be used. Cores from similar power supplies and blue-green colors are also suitable.
The transformer windings are wound in two wires and contain 2x24 turns, wire with a diameter of 1.0 mm. The beginnings of the windings are indicated by dots in the diagram.

It is advisable to use those with low open-channel resistance as output power transistors. In particular, SUP75N06-07L, SUP75N03-08, SMP60N03-10L, IRL1004, IRL3705N. And they also need to be selected with the maximum operating voltage, depending on the maximum output voltage. The maximum operating voltage of the transistor should not be less than 1.25 of the output voltage.
As a VD1 diode, you can use a paired Schottky diode, with a reverse voltage of at least 40V and a maximum current of at least 15A, also preferably in a TO-220 package. For example SLB1640, or STPS1545, etc.

The circuit was assembled and tested on a breadboard. The field-effect transistor 09N03LA, torn from a “dead motherboard”, was used as a power transistor. The diode is a paired Schottky diode SBL2045CT.

Figure 3.
Test 15V-4A.

Testing the inverter with an input voltage of 12 volts and an output voltage of 15 volts. The inverter load current is 4 amperes. The load power is 60 watts.

Figure 4.
Test 5V-8A.

Testing the inverter with an input voltage of 12 volts, an output voltage of 5V and a load current of 8A. The load power is 40 watts. Power transistor used in the circuit = 09N03LA (SMD from the motherboard), D1 = SBL2045CT (from computer power supplies), R9 = 0R068 (0.068 Ohm), C8 = 2 x 4700 10V.

The printed circuit board developed for this device is 100x38 mm in size, taking into account the installation of a transistor and diode on a radiator. Signet in Sprint-Layout 6.0 format, attached.

Below in the photographs is an assembly version of this circuit using SMD components. The signet is designed for SMD components, size 1206.

Figure 5.
Converter assembly option.

If there is no need to regulate the output voltage at the output of this converter, then the variable resistor R3 can be eliminated, and resistor R2 can be selected so that the output voltage of the converter matches the required one.

Archive for the article

Sometimes you need to get high voltage from low voltage. For example, for a high-voltage programmer powered by a 5-volt USB, you need somewhere around 12 volts.

What should I do? There are DC-DC conversion circuits for this. As well as specialized microcircuits that allow you to solve this problem in a dozen parts.

Principle of operation
So, how do you make, for example, five volts something more than five? You can come up with many ways - for example, charge capacitors in parallel, and then switch them in series. And so many many times per second. But there is a simpler way, using the properties of inductance, to maintain current strength.

To make it very clear, I will first show an example for plumbers.

Phase 1

The damper closes abruptly. The flow has nowhere else to go, and the turbine, being accelerated, continues to push the liquid forward, because cannot get up instantly. Moreover, it presses it with a force greater than the source can develop. Drives the slurry through the valve into the pressure accumulator. Where does part of it (already with increased pressure) go to the consumer? From where, thanks to the valve, it no longer returns.

Phase 3

And again the damper closes, and the turbine begins to violently push liquid into the battery. Making up for the losses that occurred there in phase 3.

Back to diagrams
We get out of the basement, take off the plumber's sweatshirt, throw the gas wrench into the corner and, with new knowledge, begin to construct the diagram.

Instead of a turbine, inductance in the form of a choke is quite suitable for us. An ordinary key (in practice, a transistor) is used as a damper, a diode is naturally used as a valve, and a capacitor takes on the role of a pressure accumulator. Who else but he is capable of accumulating potential. That's it, the converter is ready!

Phase 1

The key opens, but the coil cannot be stopped. The energy stored in the magnetic field rushes out, the current tends to be maintained at the same level as it was at the moment the key was opened. As a result, the voltage at the output from the coil jumps sharply (to make way for the current) and, breaking through the diode, is packed into the capacitor. Well, part of the energy goes into the load.

Phase 3

The key opens and the energy from the coil again breaks through the diode into the capacitor, increasing the voltage that dropped during phase 3. The cycle is completed.

As can be seen from the process, it is clear that due to the greater current from the source, we increase the voltage at the consumer. So the equality of power here must be strictly observed. Ideally, with a converter efficiency of 100%:

U source *I source = U consumption *I consumption

So if our consumer requires 12 volts and consumes 1A, then from a 5 volt source into the converter you need to feed as much as 2.4A. At the same time, I did not take into account the losses of the source, although usually they are not very large (the efficiency is usually about 80-90%).

If the source is weak and is not able to supply 2.4 amperes, then at 12 volts there will be wild ripples and a drop in voltage - the consumer will eat the contents of the capacitor faster than the source will throw it there.

Circuit design
There are a lot of ready-made DC-DC solutions. Both in the form of microblocks and specialized microcircuits. I won’t split hairs and, to demonstrate my experience, I’ll give an example of a circuit on the MC34063A that I already used in the example.

• SWC/SWE pins of the transistor switch of the chip SWC is its collector, and SWE is its emitter. The maximum current it can draw is 1.5A of input current, but you can also connect an external transistor for any desired current (for more details, see the datasheet for the chip).
• DRC - compound transistor collector
• Ipk - current protection input. There, the voltage is removed from the shunt Rsc; if the current is exceeded and the voltage on the shunt (Upk = I*Rsc) becomes higher than 0.3 volts, the converter will stall. Those. To limit the incoming current to 1A, you need to install a 0.3 Ohm resistor. I didn’t have a 0.3 ohm resistor, so I put a jumper there. It will work, but without protection. If anything, it will kill my microcircuit.
• TC is the input of the capacitor that sets the operating frequency.
• CII is the comparator input. When the voltage at this input is below 1.25 volts, the key generates pulses and the converter operates. As soon as it gets bigger, it turns off. Here, through a divider on R1 and R2, the feedback voltage from the output is applied. Moreover, the divider is selected in such a way that when the voltage we need appears at the output, there will be exactly 1.25 volts at the input of the comparator. Then everything is simple - is the output voltage lower than necessary? We're threshing. Did you get what you needed? Let's switch off.
• Vcc - Circuit Power
• GND - Ground

All formulas for calculating denominations are given in the datasheet. I will copy from it here the most important table for us:

Etched, soldered...

Just like that. A simple scheme, but it allows you to solve a number of problems.

Today we will look at several circuits of simple, one might even say simple, pulsed DC-DC voltage converters (converters of direct voltage of one value to direct voltage of another value)

What are the benefits of pulse converters? Firstly, they have high efficiency, and secondly, they can operate at an input voltage lower than the output voltage. Pulse converters are divided into groups:

• - bucking, boosting, inverting;
• - stabilized, unstabilized;
• - galvanically isolated, non-insulated;
• - with a narrow and wide range of input voltages.

To make homemade pulse converters, it is best to use specialized integrated circuits - they are easier to assemble and not capricious when setting up. So, here are 14 schemes for every taste:

This converter operates at a frequency of 50 kHz, galvanic isolation is provided by transformer T1, which is wound on a K10x6x4.5 ring made of 2000NM ferrite and contains: primary winding - 2x10 turns, secondary winding - 2x70 turns of PEV-0.2 wire. Transistors can be replaced with KT501B. Almost no current is consumed from the battery when there is no load.

Transformer T1 is wound on a ferrite ring with a diameter of 7 mm, and contains two windings of 25 turns of wire PEV = 0.3.

Push-pull unstabilized converter based on a multivibrator (VT1 and VT2) and a power amplifier (VT3 and VT4). The output voltage is selected by the number of turns of the secondary winding of the pulse transformer T1.

Stabilizing type converter based on the MAX631 microcircuit from MAXIM. Generation frequency 40…50 kHz, storage element - inductor L1.

You can use one of the two chips separately, for example the second one, to multiply the voltage from two batteries.

Typical circuit for connecting a pulse boost stabilizer on the MAX1674 microcircuit from MAXIM. Operation is maintained at an input voltage of 1.1 volts. Efficiency - 94%, load current - up to 200 mA.

Allows you to obtain two different stabilized voltages with an efficiency of 50...60% and a load current of up to 150 mA in each channel. Capacitors C2 and C3 are energy storage devices.

8. Switching boost stabilizer on the MAX1724EZK33 chip from MAXIM

Typical circuit diagram for connecting a specialized microcircuit from MAXIM. It remains operational at an input voltage of 0.91 volts, has a small-sized SMD housing and provides a load current of up to 150 mA with an efficiency of 90%.

A typical circuit for connecting a pulsed step-down stabilizer on a widely available TEXAS microcircuit. Resistor R3 regulates the output voltage within +2.8…+5 volts. Resistor R1 sets the short circuit current, which is calculated by the formula: Is(A)= 0.5/R1(Ohm)

Integrated voltage inverter, efficiency - 98%.

Two isolated voltage converters DA1 and DA2, connected in a “non-isolated” circuit with a common ground.

The inductance of the primary winding of transformer T1 is 22 μH, the ratio of turns of the primary winding to each secondary is 1: 2.5.

Typical circuit of a stabilized boost converter on a MAXIM microcircuit.

DC/DC converters are widely used to power various electronic equipment. They are used in computer devices, communication devices, various control and automation circuits, etc.

Transformer power supplies

In traditional transformer power supplies, the voltage of the supply network is converted, most often reduced, to the desired value using a transformer. The reduced voltage is smoothed out by a capacitor filter. If necessary, a semiconductor stabilizer is installed after the rectifier.

Transformer power supplies are usually equipped with linear stabilizers. Such stabilizers have at least two advantages: low cost and a small number of parts in the harness. But these advantages are eroded by low efficiency, since a significant part of the input voltage is used to heat the control transistor, which is completely unacceptable for powering portable electronic devices.

DC/DC converters

If the equipment is powered from galvanic cells or batteries, then voltage conversion to the required level is possible only with the help of DC/DC converters.

The idea is quite simple: direct voltage is converted into alternating voltage, usually with a frequency of several tens or even hundreds of kilohertz, increased (decreased), and then rectified and supplied to the load. Such converters are often called pulse converters.

An example is a boost converter from 1.5V to 5V, just the output voltage of a computer USB. A similar low-power converter is sold on Aliexpress.

Rice. 1. Converter 1.5V/5V

Pulse converters are good because they have high efficiency, ranging from 60..90%. Another advantage of pulse converters is a wide range of input voltages: the input voltage can be lower than the output voltage or much higher. In general, DC/DC converters can be divided into several groups.

Classification of converters

Lowering, in English terminology step-down or buck

The output voltage of these converters, as a rule, is lower than the input voltage: without any significant heating losses of the control transistor, you can get a voltage of only a few volts with an input voltage of 12...50V. The output current of such converters depends on the load demand, which in turn determines the circuit design of the converter.

Another English name for a step-down converter is chopper. One of the translation options for this word is interrupter. In technical literature, a step-down converter is sometimes called a “chopper”. For now, let's just remember this term.

Increasing, in English terminology step-up or boost

The output voltage of these converters is higher than the input voltage. For example, with an input voltage of 5V, the output voltage can be up to 30V, and its smooth regulation and stabilization is possible. Quite often, boost converters are called boosters.

Universal converters - SEPIC

The output voltage of these converters is maintained at a given level when the input voltage is either higher or lower than the input voltage. Recommended in cases where the input voltage can vary within significant limits. For example, in a car, the battery voltage can vary within 9...14V, but you need to get a stable voltage of 12V.

Inverting converters

The main function of these converters is to produce an output voltage of reverse polarity relative to the power source. Very convenient in cases where bipolar power is required, for example.

All of the mentioned converters can be stabilized or unstabilized; the output voltage can be galvanically connected to the input voltage or have galvanic voltage isolation. It all depends on the specific device in which the converter will be used.

To move on to a further story about DC/DC converters, you should at least understand the theory in general terms.

Step-down converter chopper - buck converter

Its functional diagram is shown in the figure below. The arrows on the wires show the directions of the currents.

Fig.2. Functional diagram of chopper stabilizer

The input voltage Uin is supplied to the input filter - capacitor Cin. The VT transistor is used as a key element; it carries out high-frequency current switching. It can be either. In addition to the indicated parts, the circuit contains a discharge diode VD and an output filter - LCout, from which the voltage is supplied to the load Rн.

It is easy to see that the load is connected in series with elements VT and L. Therefore, the circuit is sequential. How does voltage drop occur?

Pulse width modulation - PWM

The control circuit produces rectangular pulses with a constant frequency or constant period, which is essentially the same thing. These pulses are shown in Figure 3.

Fig.3. Control pulses

Here t is the pulse time, the transistor is open, t is the pause time, and the transistor is closed. The ratio ti/T is called the duty cycle duty cycle, denoted by the letter D and expressed in %% or simply in numbers. For example, with D equal to 50%, it turns out that D=0.5.

Thus, D can vary from 0 to 1. With a value of D=1, the key transistor is in a state of full conduction, and with D=0 in a cutoff state, simply put, it is closed. It is not difficult to guess that at D=50% the output voltage will be equal to half the input.

It is quite obvious that the output voltage is regulated by changing the width of the control pulse t and, in fact, by changing the coefficient D. This regulation principle is called (PWM). In almost all switching power supplies, it is with the help of PWM that the output voltage is stabilized.

In the diagrams shown in Figures 2 and 6, the PWM is “hidden” in rectangles labeled “Control circuit,” which performs some additional functions. For example, this could be a soft start of the output voltage, remote switching on, or short circuit protection of the converter.

In general, converters have become so widely used that manufacturers of electronic components have started producing PWM controllers for all occasions. The assortment is so large that just to list them you would need a whole book. Therefore, it never occurs to anyone to assemble converters using discrete elements, or as they often say in “loose” form.

Moreover, ready-made low-power converters can be purchased on Aliexpress or Ebay for a low price. In this case, for installation in an amateur design, it is enough to solder the input and output wires to the board and set the required output voltage.

But let's return to our Figure 3. In this case, the coefficient D determines how long it will be open (phase 1) or closed (phase 2). For these two phases, the circuit can be represented in two drawings. The figures DO NOT SHOW those elements that are not used in this phase.

Fig.4. Phase 1

When the transistor is open, the current from the power source (galvanic cell, battery, rectifier) ​​passes through the inductive choke L, the load Rн, and the charging capacitor Cout. At the same time, current flows through the load, capacitor Cout and inductor L accumulate energy. The current iL GRADUALLY INCREASES, due to the influence of the inductance of the inductor. This phase is called pumping.

After the load voltage reaches the set value (determined by the control device settings), the VT transistor closes and the device moves to the second phase - the discharge phase. The closed transistor in the figure is not shown at all, as if it does not exist. But this only means that the transistor is closed.

Fig.5. Phase 2

When the VT transistor is closed, there is no replenishment of energy in the inductor, since the power source is turned off. Inductance L tends to prevent changes in the magnitude and direction of the current (self-induction) flowing through the inductor winding.

Therefore, the current cannot stop instantly and is closed through the “diode-load” circuit. Because of this, the VD diode is called a discharge diode. As a rule, this is a high-speed Schottky diode. After the control period, phase 2, the circuit switches to phase 1, and the process repeats again. The maximum voltage at the output of the considered circuit can be equal to the input, and nothing more. To obtain an output voltage greater than the input, boost converters are used.

For now, we just need to remind you about the amount of inductance, which determines the two operating modes of the chopper. If the inductance is insufficient, the converter will operate in the breaking current mode, which is completely unacceptable for power supplies.

If the inductance is large enough, then operation occurs in the continuous current mode, which makes it possible, using output filters, to obtain a constant voltage with an acceptable level of ripple. Boost converters, which will be discussed below, also operate in the continuous current mode.

To slightly increase the efficiency, the discharge diode VD is replaced with a MOSFET transistor, which is opened at the right moment by the control circuit. Such converters are called synchronous. Their use is justified if the power of the converter is large enough.

Step-up or boost converters

Boost converters are used mainly for low-voltage power supply, for example, from two or three batteries, and some design components require a voltage of 12...15V with low current consumption. Quite often, a boost converter is briefly and clearly called the word “booster”.

Fig.6. Functional diagram of a boost converter

The input voltage Uin is applied to the input filter Cin and supplied to the series-connected L and switching transistor VT. A VD diode is connected to the connection point between the coil and the drain of the transistor. The load Rн and the shunt capacitor Cout are connected to the other terminal of the diode.

The VT transistor is controlled by a control circuit that produces a control signal of a stable frequency with an adjustable duty cycle D, just as was described just above when describing the chopper circuit (Fig. 3). The VD diode blocks the load from the key transistor at the right times.

When the key transistor is open, the right output of the coil L according to the diagram is connected to the negative pole of the power source Uin. An increasing current (due to the influence of inductance) from the power source flows through the coil and the open transistor, and energy accumulates in the coil.

At this time, the diode VD blocks the load and output capacitor from the switching circuit, thereby preventing the output capacitor from discharging through the open transistor. The load at this moment is powered by the energy accumulated in the capacitor Cout. Naturally, the voltage across the output capacitor drops.

As soon as the output voltage drops slightly below the set value (determined by the settings of the control circuit), the key transistor VT closes, and the energy stored in the inductor, through the diode VD, recharges the capacitor Cout, which energizes the load. In this case, the self-induction emf of the coil L is added to the input voltage and transferred to the load, therefore, the output voltage is greater than the input voltage.

When the output voltage reaches the set stabilization level, the control circuit opens the transistor VT, and the process repeats from the energy storage phase.

Universal converters - SEPIC (single-ended primary-inductor converter or converter with an asymmetrically loaded primary inductance).

Such converters are mainly used when the load has insignificant power, and the input voltage changes relative to the output voltage up or down.

Fig.7. Functional diagram of the SEPIC converter

Very similar to the boost converter circuit shown in Figure 6, but with additional elements: capacitor C1 and coil L2. It is these elements that ensure the operation of the converter in the voltage reduction mode.

SEPIC converters are used in applications where the input voltage varies widely. An example is 4V-35V to 1.23V-32V Boost Buck Voltage Step Up/Down Converter Regulator. It is under this name that the converter is sold in Chinese stores, the circuit of which is shown in Figure 8 (click on the figure to enlarge).

Fig.8. Schematic diagram of SEPIC converter

Figure 9 shows the appearance of the board with the designation of the main elements.

Fig.9. Appearance of the SEPIC converter

The figure shows the main parts according to Figure 7. Note that there are two coils L1 L2. Based on this feature, you can determine that this is a SEPIC converter.

The input voltage of the board can be within 4…35V. In this case, the output voltage can be adjusted within 1.23…32V. The operating frequency of the converter is 500 KHz. With small dimensions of 50 x 25 x 12 mm, the board provides power up to 25 W. Maximum output current up to 3A.

But a remark should be made here. If the output voltage is set at 10V, then the output current cannot be higher than 2.5A (25W). With an output voltage of 5V and a maximum current of 3A, the power will be only 15W. The main thing here is not to overdo it: either do not exceed the maximum permissible power, or do not go beyond the permissible current limits.

Thanks to the development of modern electronics, specialized current and voltage stabilizer microcircuits are produced in large quantities. They are divided according to functionality into two main types, DC DC step-up voltage converter and step-down converter. Some combine both types, but this does not affect the efficiency for the better.

Once upon a time, many radio amateurs dreamed of pulse stabilizers, but they were rare and in short supply. The assortment in Chinese stores is especially pleasing.

• 1. Application
• 2. Popular conversions
• 3. Boost voltage converters
• 4. Examples of boosters
• 5. Tusotek
• 6. For XL4016
• 7. On XL6009
• 8.MT3608
• 9. High voltage at 220
• 10. Powerful converters

Application

I recently purchased many different LEDs in 1W, 3W, 5W, 10W, 20W, 30W, 50W, 100W. All of them are of low quality, to compare them with high quality ones. To connect and power this whole bunch, I have 12 V and 19 V power supplies from laptops. I had to actively look through Aliexpress in search of low-voltage LED drivers.

Modern step-up voltage converters DC DC and step-down voltage converters were purchased, 1-2 Amperes and powerful ones 5-7 Amperes. In addition, they are perfect for connecting a laptop to 12V in a car; they will pull 80-90 watts. They are quite suitable as a charger for 12V and 24V car batteries.

In Chinese online stores, voltage stabilizers are a little more expensive.

Popular microcircuits for step-up switching stabilizers are:

1. LM2577, obsolete with low efficiency;
2. XL4016, 2 times more efficient than 2577;
3. XL6009;
4. MT3608.

Stabilizers are designated thus AC-DC, DC-DC. AC is alternating current, DC is direct current. This will make the search easier if you specify it in the request.

It is not rational to make a DC DC boost converter with your own hands; I will spend too much time on assembly and configuration. You can buy it from the Chinese for 50-250 rubles, this price includes delivery. For this amount I will receive an almost finished product that can be finalized as quickly as possible.

These switching ICs are used in conjunction with others, wrote the characteristics and datasheet for popular ICs for power supply,.

Popular conversions

Stabilizers-boosters are classified into low-voltage and high-voltage from 220 to 400 volts. Of course, there are ready-made blocks with a fixed boost value, but I prefer custom ones, they have wider functionality.

The most commonly requested transformations are:

1. 12V - 19V;
2. 12 - 24 Volts;
3. 5 - 12V;
4. 3 - 12V
5. 12 - 220V;
6. 24V - 220V.

Boosters are called car inverters.

Boost Voltage Converters

My laboratory power supply runs from a laptop unit at 19V 90W, but this is not enough to test series-connected LEDs. A series LED string requires 30V to 50V. Buying a ready-made unit for 50-60 Volts and 150W turned out to be a bit expensive, about 2000 rubles. Therefore, I ordered the first step-up stabilizer for 500 rubles. with an increase to 50V. After checking, it turned out that it reaches a maximum of 32V, because there are 35V capacitors at the input and output. I convincingly wrote to the seller about my indignation, and a couple of days later they returned my money.

I ordered a second one up to 55V under the Tusotek brand for 280 rubles, the booster turned out to be excellent. From 12V it easily increases to 60V, I didn’t turn the construction resistor higher, it would suddenly burn out. The radiator is glued with heat-conducting glue, so it was not possible to see the markings of the microcircuit. The cooling is done a little incorrectly, the heat sink pad of the Schottky diode and the controller is attached to the board, and not to the heatsink.

Examples of boosters

XL4016

..

Let's look at the 4 models that I have in stock. I didn’t waste time on photos; I took the sellers too.

Characteristics.

	Tusotek	XL4016	Driver	MT3608
Input, V	6 – 35V	6 – 32V	5 – 32V	2-24V
Input current	up to 10A	up to 10A	—	—
Output, V	6 – 55V	6 – 32V	6 – 60V	up to 28V
Output current	5A, max 7A	5A, max 8A	max 2A	1A, max 2A
Price	260rub	250rub	270rub	55rub

I have a lot of experience working with Chinese goods, most of them have shortcomings right away. Before use, I inspect and modify them to increase the reliability of the entire structure. These are mainly assembly problems that arise when quickly assembling products. I am finalizing LED spotlights, lamps for the home, car low and high beam lamps, controllers for controlling daytime running lights (DRL). I recommend that everyone do this; with a minimum of time spent, the service life can be doubled.

Be careful, not all have protection against short circuit, overheating, overload and improper connection.

The actual power depends on the mode; the specifications indicate the maximum. Of course, the characteristics of each manufacturer will be different; they install different diodes, and wind the inductor with wires of different thicknesses.

Tusotek

In my opinion, the best of all boosting stabilizers. Some elements do not have a reserve of characteristics or they are lower than those of PWM microcircuits, which is why they cannot provide even half of the promised current. Tusotek has a 1000mF 35V capacitor at the input and 470mF 63V at the output. The heat sink side with a metal plate is soldered to the board. But they are soldered poorly and askew, only one edge lies on the board, there is a gap under the other. Without looking at it, it is not clear how well they are sealed. If it’s really bad, then it’s better to dismantle them and put this side on the radiator; cooling will improve by 2 times.

A variable resistor sets the required number of volts. It will remain unchanged if you change the input voltage, it does not depend on it. For example, I set 50V at the output, increased it from 5V to 12V at the input, the set 50V did not change.

On XL4016

This converter has such a feature that it can only boost up to 50% of the input volts. If you connect 12V, then the maximum increase will be 18V. The description stated that it can be used for laptops that are powered by a maximum of 19V. But its main purpose turned out to be working with laptops from a car battery. Probably the 50% limitation can be removed by changing the resistors that set this mode. The output volts directly depend on the number of inputs.

Heat removal is much better, the radiators are installed correctly. Only instead of thermal paste there is a heat-conducting gasket to avoid electrical contact with the radiator. At the input there is a capacitor 470mF 50V, at the other end 470mF at 35V.

On XL6009

A representative of modern efficient converters, like outdated models on the LM2596, is available in several options, from miniature to models with voltage indicators.

Efficiency example:

• 92% when converting 12V to 19V, 2A load.

The datasheet immediately indicates the scheme for using as power supply for a laptop in a car from 10V to 30V. Also on the XL6009 it is easy to implement bipolar power supply at +24 and -24V. As with most converters, the efficiency decreases the higher the voltage difference and the greater the ampere.

MT3608

Miniature model with good efficiency up to 97%, PWM frequency 1.2 MHz. Efficiency increases as input voltage increases and decreases as current increases. On the MT3608 boost converter you can count on a small current, internally limited to 4A in case of a short circuit. In terms of volts, it is advisable not to exceed 24.

High voltage at 220

Conversion units from 12.24 volts to 220 are widespread among car enthusiasts like. Used to connect devices powered by 220V. The Chinese mainly sell 7-10 models of such modules, the rest are ready-made devices. Price from 400 rub. Separately, I would like to note that if, for example, 500W is indicated on a finished unit, then this will often be a short-term maximum power. Real long-term will be about 240W.

Powerful converters

For special cases, powerful DC-DC boost converters of 10-20A and up to 120V are needed. I will show you several popular and affordable models. They mostly do not have markings or the seller hides them so as not to buy them elsewhere. I haven’t personally tested them; in terms of voltage, they coexist according to the promised characteristics. But the ampere will be a little less. Although products in this price category always hold the stated load, I bought similar devices only with LCD screens.

600W

Powerful #1:

1. power 600W;
2. 10-60V converts to 12-80V;
3. price from 800 rub.

You can find it by searching “600W DC 10-60V to 12-80V Boost Converter Step Up”

400W

Powerful #2:

1. power 400W;
2. 6-40V converts to 8-80V;
3. output up to 10A;
4. price from 1200 rub.

To search, enter in the search engine “DC 400W 10A 8-80V Boost Converter Step-Up”

B900W

Powerful #3:

1. power 900W;
2. 8-40V converts to 10-120V;
3. output up to 15A.
4. price from 1400 rub.

The only unit that is designated as B900W and can be easily found.