DC voltage converter. DC-DC converters MAXIM. Capacitor conversion voltages

DC-DC converters (Convertors)– modular electronic devices, intended for supplying life buses in circuits with galvanic isolation. Installed with ready-made devices that convert constant voltage into constant voltage, vikonans in hermetically sealed housings with connectors for mounting on a separate board. Converters are distinguished by their weight, design, number of output channels, range of input and output voltages.

The companies presented a line of highly productive germs TRACO ELECTRONICі AIMTEC. The converters have high reliability and productivity, operate over a wide range of input voltages, and ensure high output flow, either one or two output channels. The small dimensions of the vibrator housings allow them to be installed in modern microelectronics with high installation density. Virobiv series TMA 0505 D, 0512 D, 0515 D It is driven by switches with a bipolar output voltage, and an output stream sufficient to power the operating power of various portable equipment with battery life.

A Japanese company presented an assortment of high-tech DC/DC transformers MURATA POWER, the possibility of a great drink looming in the various galoozes of industrial electronics. Specialized compact devices are produced in both closed, hermetically sealed housings and in open modular units for mounting on a board. A special line of modular devices are stabilized, isolated DC/DC converters with a fixed input and output voltage, which are especially required by medical technology and telecommunications equipment.

The specificity of the company's products PEAK Electronics There are unique designs of miniature DC/DC converter modules for cost-effective portable electronics. Modular devices are produced in closed, hermetic housings, with one or two non-insulated outputs, and bipolar output voltage, as well as modules that operate in voltage multiplying mode, for example , P10CU-0512ZLF, P6CU-0512ZLF.

You can admire and buy goods in our stores in the following places: Moscow, St. Petersburg, Volgograd, Voronezh, Yekaterinburg, Izhevsk, Kazan, Kaluga, Krasnodar, Krasnoyarsk, Minsk, Naberezhny Chovni, Nizhny Novgorod, Novosibirsk, Omsk, Perm, Ro stov- on the Don, Ryazan, Samara, Tver, Tomsk, Tula, Tyumen, Ufa, Chelyabinsk. Delivery by mail, through the Pickpoint delivery system or through Euroset salons to the following places: Tolyatti, Barnaul, Ulyanovsk, Irkutsk, Khabarovsk, Yaroslavl, Vladivostok, Makhachkala, Tomsk, Orenburg, Kemerovo, Novokuznetsk, Astrakhan, Penza, Lipetsk, Kirov , Cheboksary, Kaliningrad, Kursk, Ulan-Ude, Stavropol, Sochi, Ivanovo, Bryansk, Bilgorod, Surgut, Volodymyr, Nizhny Tagil, Arkhangelsk, Chita, Smolensk, Kurgan, Orel, Vladikavkaz, Grozny, Murmansk, Tambov, Petrozavodsk, Kostroma, Ni Zhnyovartov , Novorossiysk, Yoshkar-Ola and in.

You can buy products from the “DC-DC converters (Convertors)” group in bulk or in bulk.

LM2596 reduces the input voltage (up to 40 V) - the output is regulated, 3 A power. Ideal for LEDs in the car. Very cheap modules - about 40 rubles from China.

The Texas Instruments company produces clear, reliable, affordable and cheap, manual DC-DC controllers LM2596. Chinese factories produce low-cost stepdown converters on this basis: the price of a module for LM2596 is approximately 35 rubles (including delivery). I would like to buy a batch of 10 pieces at once - for them there will always be a shortage, at which the price will drop to 32 rubles, and less than 30 rubles if 50 pieces are ordered. A report about the design of microcircuits, flow and voltage regulation, its operation and the disadvantages of the converter.

A typical method of vibration control is to stabilize the voltage. On the basis of this stabilizer it is easy to create a pulse life block, which I describe as a simple and reliable laboratory life block that is visible to a short circuit. The stench has added to the steel of the yakness (it seems that all the stench is produced at one plant - it’s easy to make decisions on five parts), and the datasheet and stated characteristics have become more consistent.

Another area of stagnation - pulse stabilizer for life of light-emitting diodes. The module on this microcircuit allows you to connect a 10-watt automotive LED matrix, further ensuring short-circuit protection.

I highly recommend buying a dozen of them - you will definitely need them. The stinks are unique in their own way - the input voltage is up to 40 volts, and only 5 external components are required. This is easy - you can increase the voltage on the power supply bus of a smart phone to 36 volts by changing the cable girders. At living points we install such a module and configure it to require 12, 9, 5 volts or as needed.

Let's take a look at their report.

Microchip characteristics:

Input voltage – 2.4 to 40 volts (up to 60 volts for the HV version)
Output voltage - fixed or regulated (from 1.2 to 37 volts)
Output flow – up to 3 amperes (with good cooling – up to 4.5A)
Conversion frequency – 150 kHz
Housing - TO220-5 (door mounting) and D2PAK-5 (top mounting)
ECC - 70-75% at low voltages, up to 95% at high voltages

Dzherelo stabilized voltage
Redesign scheme
Datasend
USB charger based on LM2596
Stabilizer struma
Zastosuvannya at self-built outbuildings
Regulation of output flow and voltage
Improved analogs of LM2596

History - linear stabilizers

For starters, I’ll explain why the standard linear transformer voltages on the LM78XX (for example 7805) or LM317 are bad. The yoga axis is simplified diagram.

The main element of such a converter is a hard-wired bipolar transistor, which switches on at its “end-to-end” value like a hardened resistor. This transistor is connected to the Darlington bet (to increase the coefficient of transmission of the current and reduce the voltage required to process the circuits). The base flow is set by the operational booster, which amplifies the difference between the output voltage and the one set by the auxiliary ION (reference voltage resistor), then. vin inclusions following the classic scheme of booster milking.

In this way, the operator simply turns on the resistor in series with the voltages, and supports it with a support so that, for example, exactly 5 volts are extinguished at the voltage. It is not important to note that when the voltage is reduced from 12 volts to 5 (even a frequent occurrence of the 7805 microcircuits being stagnant), the 12 volt inputs are distributed between the stabilizer and the settings of up to 7 volts per stabilizer izatori + 5 volts on the vantage.” On a half-ampere stream, 2.5 W is visible on the vantage, and as much as 3.5 W on the 7805.

It turns out that the “signal” of 7 volts is simply extinguished on the stabilizer, turning into heat. In the first place, problems with cooling arise through this process, and in another way, a lot of energy comes from the source of life. With a power outlet, it’s not at all scary (although it’s still a concern for the ecology), but with a battery or rechargeable battery, you can’t help but remember.

Another problem is that with this method it is impossible to transform what is going on. Often such a need arises, and if you try to figure it out twenty or thirty times you will be surprised by how complex the synthesis and development of such schemes is. One of the simplest circuits of this kind is a 5-15V push-pull switch.

It is necessary to know that in order to ensure galvanic isolation, the protection does not effectively vikorist transformer - at the same time, only half of the primary winding is covered.

Let's forget this bad dream and move on to the current circuit design.

Dzherelo voltage

Scheme

Micro -grinding is a zruchnaya jacket step -drin converter: the attachment of the bipolar key is known to be a worship, the component of the regulator - Shvidsky dioD, INDIDENT, INDYKENTY IN VIHID CANDADER, I can put it on the wxid condenser - VXID CANTASION - VSIA - her.

The LM2596ADJ version also requires an output voltage setting circuit, either two resistors or one variable resistor.

Scheme of a voltage reduction switch based on LM2596:

The whole scheme at once:

Here you can download datasheet for LM2596.

The principle of operation: when a PWM signal is applied to a pressed key in the middle of the device, voltage pulses are applied to the inductance. At point A x% of the hour the voltage is equal, and (1–x)% of the hour the voltage is equal to zero. The LC filter smoothes the vibration, showing a stable warehouse, which is older than x * life voltage. The diode switches off if the transistor is switched on.

Detailed description of the work

The inductance is repaired by changing the flow through it. When voltage appears at point A, the throttle creates a large negative self-induction voltage, and the voltage at the point becomes equal to the difference between the life voltage and the self-induction voltage. The inductance flow and voltage at the desired stage gradually increase.

After the voltage drops at point A, the throttle fails to save the excess current that flows from the capacitor and shorts it through the LED to ground - the voltage gradually drops. Thus, the voltage at the input voltage is less than the input voltage and lies under the impulse tension.

Output voltage

The module is available in four versions: with voltage 3.3V (index –3.3), 5V (index –5.0), 12V (index –12) and regulated version LM2596ADJ. It’s almost painful to note the version itself that is being adjusted, as there are a lot of leftovers in the warehouses of electronic companies and you are unlikely to face a shortage of them - and they only cost an additional two kopecks The original resistor. Well, of course, the 5 volt version is also gaining popularity.

The quantity in stock is in constant storage.

You can determine the output voltage at the DIP switch view, a good example of this guidance is here, or at the rotary switch view. In both cases, a battery of precision resistors is required - then you can adjust the voltage without a voltmeter.

Frame

There are two housing options: a housing for planar mounting TO-263 (model LM2596S) and a housing for mounting in a door TO-220 (model LM2596T). I give preference to the stock planar version of the LM2596S, since the board itself is the heatsink, and there is no need to buy an additional external heatsink. In addition, the mechanical resistance of the device is rich, in addition to the TO-220, which requires that it be screwed as far as possible in order to install it before payment - otherwise it is easier to install the planar version. I recommend using the LM2596T-ADJ microcircuit in life blocks, since it is easier to transfer a lot of heat to the body.

Smoothing by pulsating input voltage

It can be used as an effective intelligent stabilizer after straightening the struma. The fragments of the microcircuit follow the value of the output voltage, the fluctuation of the input voltage results in a proportional change in the conversion coefficient of the microcircuit, and the voltage will be normal.

This means that with the LM2596 as a step-down converter after the transformer and rectifier, the input capacitor (the same as the one that costs after the diode bridge) can have a small capacitance (about 50-100 microns) F).

Output capacitor

Due to the high frequency of reversal of the output capacitor, it is also due to its high capacitance. However, a hard-working person will not be able to significantly plant this capacitor per cycle. Let’s carry out the design: take a 100 µF capacitor, 5 V output voltage and a voltage that equals 3 amperes. The additional charge of the capacitor is q = C * U = 100e-6 µF * 5 = 500e-6 µC.

In one cycle of reversal of the voltage taken from the capacitor dq = I * t = 3 A * 6.7 µs = 20 µC (that’s only 4% of the total charge of the capacitor), a new cycle begins, and a new portion of energy is transferred into the capacitor.

Above all, do not use tantalum capacitors as input and output capacitors. They write right in the datasheets - “do not vikorist in life cycles”, which is why it is really bad to endure short-term voltage fluctuations, and do not like high impulse streams. Vikorist original aluminum electrolytic capacitors.

Efficiency, efficiency factor and heat loss

The CCD is not so high, since the bipolar transistor is damaged as the key is pressed, and there is a non-zero voltage drop, about 1.2V. Increases and decreases efficiency at low voltages.

As a matter of fact, maximum efficiency is achieved when the difference between the input and output voltage is approximately 12 volts. If you need to change the voltage to 12 volts, it will heat up with a minimum amount of energy.

What is the effectiveness of transformation? This is the value that characterizes strum losses - the heat generated on the surface of an open pressure key according to the Joule-Lenz law and similar losses during transition processes - if the key is open, perhaps, by less than half. The effects of both mechanisms can be equalized depending on the magnitude, so do not forget about the ways of spending. There is little effort involved in the transformation of the “brains” themselves.

Ideally, when the voltage is reversed from U1 to U2 and the output stream I2, the output voltage is equal to P2 = U2 * I2, the input voltage is equal to it (ideal voltage). Then, the input stream becomes I1 = U2/U1*I2.

In our type of transformation, the efficiency is less than one, so some of the energy will be lost in the middle of the process. For example, when η is effective, the output pressure becomes P_out = η*P_in, and the input P_loss = P_in-P_out = P_in*(1-η) = P_out*(1-η)/η. Naturally, the distortion will increase the input stream in order to maintain the desired output stream and voltage.

It can be noted that when the 12V is converted -> 5V and the output current is 1A, the consumption in the microcircuits adds up to 1.3 Watt, and the input current is equal to 0.52A. In any case, it is better for any linear converter, which will give at least 7 watts of expenditure, and the output from the input limit (including the one on the right) is 1 ampere - twice as much.

Before speaking, the LM2577 microcircuit has a lower frequency of operation, and it is more efficient, and there are fewer costs in transient processes. However, they require higher ratings of the inductor and the output capacitor, and at the cost of money and the size of the payment.

Increased output stream

It doesn’t matter if you need a large output stream of microcircuits, sometimes you need an even larger stream. How to get out of this situation?

You can parallelize a number of transformations. Of course, the stench of the culprits was tuned to exactly the same voltage. In this case, you cannot get by with simple SMD resistors in the Feedback voltage setting; you need to adjust the resistors with an accuracy of 1%, or manually set the voltage with a changeable resistor.

There is no harm in a small voltage difference - rather than paralleling it through a small shunt, about a few tens of miles. Otherwise, everything that needs to be done will rest on the shoulders of the driver with great tension and may not turn back. 2. You can use good cooling - a large radiator, a large-area board with a large surface area. This gives the ability to [raise the strings](/lm2596-tips-and-tricks/ “The installation of LM2596 in devices and the dilution of the board”) up to 4.5A. 3. You can [insert a strong key](#a7) behind the microcircuit housing. This makes it possible to freeze the field-effect transistor with even small voltage drops and increase both the output flow and the CCD.

USB charger for LM2596

You can create an even handy portable USB charger. For this you need to adjust the regulator to a voltage of 5V, provide it with a USB port and ensure the life of the charger. I recommend purchasing a radio-model lithium-polymer battery from China that will provide 5 ampere-years at a voltage of 11.1 volts. This is very rich - enough for that 8 times charge your original smartphone (not the CCD). Z urahuvannyam KKD viyde schonaymenshe 6 times.

Do not forget to close the contacts D+ and D- of the USB socket to inform the phone that there are no connections to the charger and no connection. Without any doubt, the phone will not be connected to a computer, and will be charged with a 500mA supply - for a long time. Moreover, such a charge may not compensate for the cost of the phone, and the battery will not be charged at all.

You can also transfer the 12V input from a car battery to the cigarette lighter socket - and re-micerate the device as a re-mitter. Please install a LED that signals when the device is turned off, so that you don’t forget to turn the battery on after charging again - otherwise you will spend a lot of time recharging the backup battery for a few days.

Such a battery does not need to be suitable, because there are no risks at high rates - you can try to find a smaller high-current battery, and you will have a smaller size and voltage.

Stabilizer struma

Regulation of the output stream

Only the version with an output voltage that can be adjusted is available (LM2596ADJ). Before speaking, the Chinese are purchasing this version of the board, with voltage regulation, flow and all indications - a ready-made stabilizer module for the power supply on LM2596 with short-circuit protection, can be purchased under the name xw026fr4.

If you don’t want to put together a ready-made module and want to create this circuit yourself - there’s nothing complicated, with one caveat: the microcircuit does not have the ability to control the strum, protection can be added. I’ll explain how to do it, and I’ll explain the difficult points clearly.

Zastosuvannya

A struma stabilizer is a thing that is needed to revive the light-emitting diodes (before speaking, this is my microcontroller project) Dimming LED drivers), laser diodes, galvanics, battery charge. As with voltage stabilizers, there are two types of such devices – linear and pulse.

The classic linear stabilizer is the LM317, and it is very high in its class - but its limiting strum is 1.5A, which is not enough for rich high-voltage LEDs. However, if you combine this stabilizer with an external transistor, the costs are simply unpleasant. The whole world is burning a barrel for energy-saving light bulbs, but here LM317 works with a CCD of 30%. This is not our method.

And the axis of our microcircuit is a manual driver of a pulse voltage converter, which has many operating modes. Spend minimally, the remains will not stagnate in the same linear modes of operation of transistors, except the key one.

It was originally intended for voltage stabilization circuits, using a number of elements to transform them into a stabilizer current. On the right is that the microcircuit relies heavily on the “Feedback” signal as a turning link, and the axis that feeds the new one is already ours on the right.

In the standard switching circuit, voltage is supplied to this leg from the resistive output voltage. 1.2V is more equal, since the Feedback is smaller, the driver increases the impulse distortion, and if it is larger, it changes. You can also apply voltage to this input from the struma shunt!

Shunt

For example, for a 3A circuit, it is necessary to take a shunt with a nominal value of a little more than 0.1 Ohm. On such a support, this power supply is close to 1W, which is also quite a lot. It is better to parallelize three such shunts, with a reference voltage of 0.033 Ohm, a voltage drop of 0.1 V and a heat generation of 0.3 W.

However, the Feedback input draws a voltage of 1.2V - but we can only draw 0.1V. It is irrational to install a larger support (there is 150 times more heat), which means you will not be able to increase the voltage. Try to get help from the surgical assistant.

Pіdsiluvach, which does not invert, on the op-amp

It’s a classic scheme, what can we do to make it simpler?

Ob'ednuyemo

Now we create a primary circuit that converts the voltage and power supply to the LM358 op-amp, and connects the strum shunt to the input of which.

A tightened resistor 0.033 Ohm is a shunt. This can be created with three 0.1 Ohm resistors connected in parallel, and to increase the permissible voltage that is dissipated - vikorist SMD resistors in the 1206 package, place them with a small gap (not squeezing) and try to keep the media ball as much as possible from the resistors. A small capacitor is connected to the Feedback output to prevent possible transition to oscillator mode.

Adjustable both flow and voltage

Let's introduce offensive signals to the Feedback input - both flow and voltage. To connect these signals, we use a high-speed electrical wiring diagram “I” on the diodes. If the flow signal is more than a voltage signal, it will dominate and be the result.

A few words about the stagnation of the circuits

You cannot adjust the output voltage. If you want to regulate both the output flow and the voltage at the same time, they are proportional to each other, with a coefficient of “opportunity”. And if the life block implements the scenario on the command “the voltage is constantly output, but when the current is moved, the voltage begins to change,” then. CC/CV is also a charging device.

The maximum operating voltage of the circuit is 30V, circuit breakers for LM358. You can expand the range up to 40V (or 60V with the LM2596-HV version) to use an op-amp from a zener diode.

In the remaining option, to sum up the diodes, it is necessary to separate the same assembly, since it contains the result of generation within the same technological process on one silicon wafer. The range of their parameters will be much smaller than the range of parameters of other discrete diodes - which will therefore result in a high accuracy of value estimation.

You also need to be careful so that the op-amp circuit does not wake up and go into generation mode. For this purpose, please change the voltage of all conductors, especially the track connected to pin 2 of the LM2596. Do not move the op-amp near this track, but move the SS36 diode and filter capacitor closer to the LM2596 case, and ensure a minimum area of the ground loop connected to these elements - it is necessary to ensure and the minimal dovezhna way of the gate struma "LM2596 -> VD/C -> LM2596".

Zastosuvannya LM2596 at annexes and independent dilution of payment

About the storage of microcircuits in my devices, not looking like a finished module, I reported to Other statistics, including: selection of diode, capacitors, inductor parameters, as well as information about the correct wiring and many additional tricks.

Possibility of further development

Improved analogs of LM2596

The easiest way is to go to LM2678. In essence, this is the same stepdown conversion, only with a field-effect transistor, in which case the CCD rises to 92%. True, there are 7 instead of 5, and it’s not pin-to-pin crazy. This microcircuit is very similar, and will be a simpler option due to increased efficiency.

L5973D- Add the old microcircuit, which will provide up to 2.5A, and a little more CCD. It also has a twice as high conversion frequency (250 kHz) - therefore, smaller inductance and capacitor ratings are required. However, I’m sure that I’ll have to deal with it if I put it directly in the car’s lane - it’s often interrupted by wrong codes.

ST1S10- Highly efficient (CCD 90%) DC-DC stepdown conversion.

Requires 5-6 external components;

ST1S14- High-voltage (up to 48 volts) controller. The operating frequency is high (850 kHz), the output stream is up to 4A, the output is Power Good, the high efficiency factor (not higher than 85%) is the circuit that protects the flow of the stream from the need to break it, melodiously, in the best way for the life of a server using a 36-volt device.

If you need maximum CCD, you will have to resort to non-integrated DC-DC controllers. The problem with integrated controllers is that they do not contain high-quality power transistors - the typical channel input is no more than 200 mOhm. However, if you take a controller without a built-in transistor, you can select any transistor, even AUIRFS8409-7P with support for the channel in the memory

DC-DC conversion from an external transistor

The part is coming

Technical characteristics
● Input voltage range: 4-32V (maximum 36V)
● Output voltage range: 1.2-32V (adjustable, optional - 5V)
● Output flow: 0-15A
● Conversion coefficient: 98%
● Operating temperatures: -40 to +85 °C
● Operating frequency: 150KHz

Vart_st at the time of order 10/28/2016:

Supplied sealed in an antistatic bag

Structurally, the viconica is without a body,

Installation is double-sided, most elements are placed on the top side. There are not a lot of elements on the bottom, and its height does not exceed the installation of the converter into the housing.

The dimensions of the extension are 5 cm

At 6 cm

Strum 15 A surrounding the fusible igniter at the converter input

At the output there is an LED that indicates the supply of input voltage to the converter, and an adjusting resistor for setting the output voltage. It is not possible to cut off the output stream on this converter

Electricity for 470 mf 35 V

Diode SS 54

Installation of the markings is very difficult and photographing the markings of the elements is difficult. If there are a lot of circuits for such and similar converters, I will be more focused on testing and testing.

I have tested a life block and a converter from two of my past reviews, sent to what kind of equipment I have, as well as 60 watts of electronic equipment.

The first time it was turned on, there was no change in the converter adjustment, the voltage was 0.5 A. The converter had a voltage of 5.5 Volts

With an input voltage of 14 Volts, the converter reaches a maximum of 13.84 V, which makes the claims 98%

At 21.91 At the input - the maximum became 21.67 At - the maximum 99%

Now for the stability test. A 2A voltage supply is installed, the voltage is set to 12 V. The input voltage is gradually reduced from 22 to 13 V. At which the output parameters have not changed at all

Even when the input voltage was reduced to 12 V, a drawdown appeared - 11.76 V - the same as 98%

For testing at 15 A, I will select a stand practically similar to testing high-strength batteries. As a result, an assembly of 10 parallel-connected ceramic resistors of 2 Ohms, 10 Watts has been designed. The ground support is collected at approximately 0.2 Ohm - it is protected under voltage. The voltage on the converter is set to a minimum of 1.2 Volts.

When the navigation is turned on, 1.2 sits about 1.09. Strum - 5.54 A

I smoothly raise it to 15 A

For beauty, I set it to 3 V, for power - 15.66 A. I left it like this until the resistors became noticeably stinky due to overheating:) The converter itself is slightly warm. Trival test for 50 watts - the video has a lower one.

As I said, a converter is not required to create a power supply unit at 5 V. Therefore, it is important to use it in various applications in the voltage range of 4.7-5.2 V.

The converter is adjusted to exactly 5 V at a voltage of 1 A. Smoothly moving the voltage to 10 A and I am careful about the drawdown.

As can be seen in the photo below, at 10 A, the voltage is out of the permissible range - 4.79 V

In the video below you can see the heating rate of the converter at a one-year voltage of 50 Watts - 5 V, 10 A. To make it easier to watch, the video is sped up 10 times, so no one cares to scroll through it.

During the first 10 weeks, the DC-DC converter heats up to 40 degrees, and until the end of the test it practically does not change the temperature, at the end of the test the temperature drops to 42-43 degrees.

For my purposes, a modern power supply for one-hour charging and life of many gadgets allows it to fit perfectly, does not overheat, stability when changing the input voltage and increased current flow - in admin.

Thank you for your respect, I’m willing to look around and look brown.

I plan to buy +46 Dodati in attire Look around worthy +31 +69

MAXIM Integrated Products is today a leading light leader in the development and production of a wide range of integrated circuits for the most demanding areas of microelectronics. The company uses the technology of transformation of tension to make a personal decision. The range of manufactured microcircuits-converters covers almost the entire totality of current electronics needs in this area. The article will look at the possibilities of various constant voltage transformers from the MAXIM company.

Apparently, the basis of the operation of a pulse converter is the process of transferring energy from the input to the output through the recommutation of the reactive element with a singing frequency. In this case, the converters are divided into two groups - inductive and capacitor (Fig. 1).

Inductive reversal voltages

Inductive DC/DC converters are represented by the MAXIM company in the widest range. 218 different inductive converter microcircuits are produced:

move (Step-Up);
step-down;
moving/lowering (Step-Up/Down);
inverting (Inverter).

Inductive converters MAX1724 and MAX1709, which will advance.

The MAX1724 is a high-efficiency (efficiency efficiency up to 90%) converter that moves, available in a thin 5-pin SOT23 package. It has a uniquely low level of quiet current - about 1.5 µA. This device is specially developed by MAXIM for use in portable portable devices powered by one or two alkaline or NiMH batteries. The lower range of the input voltage of the microcircuits is set to 0.8 V. The demand converter is based on a synchronous rectifier circuit, which turns off the need for an external Schottky diode. Therefore, to ensure a successful transformation, it is necessary to have only 3 external elements (Fig. 2). To reduce electromagnetic disturbances, the MAX1724 uses a high-voltage noise reduction circuit that is generated. The built-in switches on N-channel field-effect transistors will ensure the output flow of up to 150 mA at the output voltage of 2.7 to 5 (depending on the type of microcircuit). Okremia visnovok/SHDN (Fig. 2) allows you to robotically recreate it. The flow in Shutdown mode does not exceed 0.1 µA.

In cases where it is necessary to ensure the life of a tight demand, the MAXIM company offers another solution - MAX1709. This device provides an output voltage of up to 4 A with an input voltage of 3.3 V. The input voltage range lies between 0.7 and 5 V. This ensures the ability to use MAX1709 microcircuits in the device to live in One battery for 1, 2 V. The fixed frequency of the re-micrification will ensure that the robot switches at the frequency of the fundamental harmonic, which is higher than 600 kHz. Selecting a specific frequency allows you to use simple noise reduction filtering circuits. In addition, the frequency of the switching is increased, which reduces the size of the inductor that is vicorized. If necessary, the converter can operate at the frequency of an external generator (from 350 kHz to 1 MHz), which is connected to the CLK pin (Fig. 3). By changing the values of external components, it is possible to program the robot in the “soft start” mode, as well as limit the maximum flow of pressure. It is important for us to install batteries in the minds of life.

It should be noted that, despite the fact that the above devices can operate with a reduced input voltage of up to 0.7 -0.8 V, they can provide greater efficiency to the operation of various portable devices powered by batteries, etc. driving their very lively jabs.

Minimum inductive converter MAX1917

It is urgently possible, prior to the miniaturization and decrease in the yield of the terminal virus, to encourage the breeders to continuously optimize the characteristics of their developments. For example, you can use the MAX1917 DC/DC converter, which is used for complex storage of DDR memory. This transformation of needs is based on the Quick-PWM™ architecture developed by MAXIM. It allows you to ensure even a short hour of activating the circuits that it controls by changing the control circuit. As a result, the volume and capacitance of the capacitors at the output of the converter decreases. Figure 4 shows the circuit diagram for turning on the converter.

The MAX1917 microcircuit provides control of N-FET switches, allowing the implementation of a step-down synchronous rectifier with a flow that flows in or out, in a voltage of up to 25 A at a voltage of up to 3.6 V. The maximum efficiency factor can reach values and 96% with a flow of one ampere. The advanced QCD combines, simultaneously, reading information about the strut near the drain-turn junction of the lower field-effect transistor in the arm. This allows you to do without the need for a special resistor as a flow sensor that turns off your heat loss.

The frequency of mixing of MAX1917 microcircuits can be selected from the 200th row; 300; 400; 550 kHz. During the process of stabilization of the output voltage, the frequency changes to fall between the input voltage and the input voltage.

The output voltage is set via the DDR input. With additional external elements, parameters are set for the implementation of maximum flow and “soft start” circuits.

In Fig. 5, the readings show a graph of voltage changes on the struma applied at different times from 2.5 to 18 A. The oscillogram shows that the voltage change time when changing the struma does not exceed 20 µs.

Regardless of those descriptions of the devices of the creations, first of all, for stagnation in the system of living DDR-memory, they can be used as a lower conversion of the hidden value of the alternating frequency of the intercom.

Currently, the MAXIM company produces a large number of specialized reduction converters for various drying applications:

mobile phone life systems (MAX1820-1821, MAX1958-1959);
Peltier module drivers (MAX1968-1969, MAX8520-8521);
laptop life systems (MAX1534, MAX1710-1712, MAX1717-1718, MAX1791, MAX1844);
living systems for current CPUs (MAX797798, MAX1624-MAX1625, MAX1638-1639).

The low-voltage converters that are available now support a range of output currents up to 60 A (MAX5041). Many devices operate at very high intermic frequencies - 1.2 MHz (MAX1734, MAX1921), 1 MHz (MAX1821), which allows you to increase the tension of the life blocks due to the reduction in the size of the reactive elements, so transmit energy.

Up/down converter MAX1672

Perhaps the MAX1672 is the most functional MAXIM converter of this type. Available in a very small QSOP package, it provides an output voltage in the range of 1.25 to 5.5 at a current of 300 mA without an external transistor (Fig. 6). The conversion is effective at an input voltage of 1.8 to 11 V. The typical CCD when operating in the "Step-Up" mode becomes 85%.

The MAX1672 converter is a device that combines two different voltage conversion methods and is not the classic Cook converter. To move the voltage to the storage unit, a converter is included, which is based on a built-in N-channel MOSFET transistor and a miniature external inductance coil (10 μH). The decrease in voltage is determined by the use of a linear "low-drop" regulator behind the help of a P-FET transistor.

There are 3 different operating modes for the MAX1672:

The input voltage is lower than the output voltage - the converter is working, which is moving.
The input voltage is a little more than the output voltage - at the most efficient operating mode - use a converter that moves and a linear regulator. In this mode, the controller that moves automatically boosts the voltage at the input of the linear regulator, which is necessary for its operation. The graph of the CCD ratio versus the input voltage (Fig. 7) shows that at this moment the peak efficiency is reached - the CCD is over 94% (with an input voltage of 10 mA). In addition, the active linear regulator effectively filters the high-frequency noise of the converter, which is moving.
The input voltage is significantly greater than the output voltage - only the linear regulator operates, and the efficiency drops as the input voltage increases.

The output voltage can be either changeable (with the help of external resistors) or fixed - the change in value (3.3 or 5 V) is carried out at the “3/5” input. The microcircuit contains a low voltage detector (PGO), the parameters of which can be set with the help of a voltage sensor connected to the PGI circuit. In the Shutdown mode, the voltage is switched on at the input, and the current consumption of the microcircuits is reduced to 0.1 µA.

The system implemented in the application protects against overheating, the pass-through transistor is switched off when the crystal temperature is raised to +150 °C and turns on again when cooled to +20 °C. A circuit for exchanging the maximum flow through the inductance coil has been created that allows you to select two values: 0.5 and 0.8 A.

Voltage inverters MAX774, MAX775 and MAX776

The group of MAX774-MAX776 microcircuits is a set of inverters that are characterized by consistently high efficiency over a wide range of current flows. They differ only from the values of the output voltage, so it is enough to look at the features of one converter - MAX774 with a negative output voltage of -5 Art.

The microcircuit is designed to drive voltage inverters from the viscosity of the external P-FET transistor and provide an efficiency factor of 85% in the voltage range of 5 mA to 1 A. This has become possible in future implementations Adopt a unique control circuit that leverages the benefits of Pulse Frequency Modulation (PFM) pulse skipping (ultra-low flow rate), and high efficiency converter with pulse width modulation (PWM) at high pressures.

Capacitor conversion voltages

To liven up low-voltage applications, such as LCD, VCO (voltage-cooled generators), and even tuning, it is already necessary to reverse the voltages on the capacitors that are switched. The installation of such devices does not require inductive (winding) components; they allow the creation of cheap and small-sized life modules. The MAXIM company produces a large number of similar converters that can be either fixed input voltage or adjustable.

Figure 8 shows a typical connection circuit for a MAX889T regulated capacitor converter. VIN will ensure a stabilized voltage at the vantage point in the range of -2.5 to -Vin at a flow of 200 mA. This device operates at a frequency of 2 MHz, which allows even small external capacitors to be used, and thus improves its current flow. The circuit board /SHDN allows the operation of microcircuits with the help of external logic (control flow no more than 0.1 µA).

As in most other DC/DC converters from MAXIM, this device has a “soft start” function, circuit breaker at the time of startup, protection circuits against short circuits and overheating of the crystal.

There are also bipolar capacitor converters at different voltage values (MAX768, MAX864, MAX865), sub-voltages (MAX680, MAX681) and so on.

Convert to bipolar voltage (Balanced)

Most of the specialized unipolar voltage converters from the bipolar MAXIM company are available on various versions of capacitor converters. However, it is important for them to be victorious in order to live up to their desires. Therefore, there is a need to create a tight bipolar reversal switch after applying pressure to the MAX742 and MAX743 microcircuits. The first one uses two external transistors and ensures a voltage of up to 60 W, while the other has internal field-effect transistors and allows the connection of a voltage of up to 3 W.

The MAX742 DC/DC converter is suitable for power supply units ranging from 3 to 60 W. By replacing two independent inductance coils, this device (in addition to the version with a transformer) ensures separate voltage regulation at the skin level with an accuracy of 4%. The conversion operates at a frequency of 100 or 200 kHz with PWM switches. VIN converts the input voltage (from 4.2 to 10 V) to the output voltage ±12 or ±15 V (the voltage must be installed behind an additional special output). The CCD at an intermic frequency of 100 kHz is the highest - up to 92%. The maximum value of the struma in the area of the skin shoulder is ±2 A.

Richly functional DC/DC converters

The process of advanced stage of integration and natural degradation of a large number of discrete components in the terminal virus leads to the appearance of a variety of richly functional microcircuits, including in the sphere of voltage conversion. The MAXIM company produces a wide range of richly functional life controllers for modern sectors of the economy:

digital cameras and video cameras (MAX1800-MAX1802);
RC monitors TFT (MAX1880-MAX1885, MAX1889, MAX1998);
CPU/GPU (MAX1816, MAX1994);
main controllers of the life system in laptops (MAX1901, MAX1997, MAX1999);
xDSL/cable modems (MAX1864, MAX1865);
satellite phones (MAX888, MAX1863);
Kishenkov computer PDA (MAX781);
life of CCFT backlight lamps and LCD controllers (MAX753,MAX754).

The main feature of these devices is the stagnation in a specific area, and the identification of several outputs from different voltage levels. The butt may be the MAX1800 microcircuit, intended for use in the life system of a digital camera or video camera. The VON operates at an input voltage of 0.7 to 5.5 V. A whole range of voltages vibrates at the outputs of the converter (CCD up to 95%):

+3.3 (up to 1.5 A) - head output, logic control;
+15 and -7.5 V - vitalization of the CCD matrix;
+18 and +12 V - life of the LCD module;
+7 - CCFL life;
+1.8 V – MCU grub (CORE).

In addition, the MAX1800 controller (Fig. 10) can be combined with one or more additional MAX1801 microcircuits to power miniature electric motors.

The table shows low characteristics of current DC/DC converters from MAXIM.

Table. Main characteristics of DC/DC converters from MAXIM

Name	Function	Minimum input voltage, V	Maximum input voltage, V	Fixed output voltage, V	Minimum output voltage, V	Maximum output voltage, V	Typical output stream, which is provided by a micro-circuit, A	Intermic frequency, kHz	Frame
MAX680	Balanced	2	6	-2xVin +2xVin	-	-	0,01	8	8/PDIP-300 8/SO-150
MAX768	Balanced	2,5	5,5	±5	±1.25	±11	0,005	240	16/QSOP
MAX889	Capacitor Regulated	2,7	5,5	-Vin	–2,5	–5.5	0,2	2000	8/SO.150
MAX1044	Capacitor Unregulated	1,5	10	-Vin +2xVin	-	-	0,02	20	8/PDIP.300 8/SO.150 8/µMAX
MAX1774	Step-Down	2,7	28	1,8 3,3	1	5.5	2	600	28/QSOP
MAX1917	Step-Down	4,5	22	-	0,4	5	25	200–550	16/QSOP
MAX765	Inverter	3	16,5	–12	–1	–16	0,12	300	8/PDIP.300 8/SO.150
MAX776	Inverter	3	16,5	–15	0	–100	1	300	8/PDIP.300 8/SO.150
MAX1724	Step-Up	0,8	5,5	2,7; 3; 3,3; 5	-	-	0,15	-	5/SOT23-Thin
MAX1709	Step-Up	0,7	5	3,3; 5	2,5	5,5	4	600	16/SO.150
MAX711	Step-Up/Down	1,8	11	-	2,7	5,5	0,25	300	16/SO.150
MAX1672	Step-Up/Down	1,8	11	3,3; 5	1,25	5,5	0,26	-	16/QSOP
MAX1800	Multifunction	0,7	5,5	-	-	-	-	1000	32/TQFP-5.5

Literature

MAXIM full-line CD-Catalog, 2002 Edition.
Yeranosyan S.A.Merezhevi living blocks with high-frequency conversion.L.: Energoatomizdat. Leningr.vdd-nya. 1991.
Integrated microcircuits: Microcircuits for pulse generators for life and their stagnation. Vidannya 2-ge.M.: DODEKA.2000.
International Rectifier. Power transmission devices. Translation from English per ed. V.V. Tokariova. Pershe vidannya. Voronizh. 1995.