Schematic diagram of the boost converter board 3.7 5 volts. How to get custom voltage. AC voltage boost
Boost converter 3.6 - 5 volts on MC34063
There are plenty of articles about converters on the MC34063 and similar microcircuits. Why write another one? We admit honestly, we wrote it to lay out a printed circuit board. Perhaps someone will consider it successful or just too lazy to draw their own.
You may need such a converter, for example, to power a homemade product or a measuring device from a lithium battery. In our case, this is the power supply of the dosimeter from the Chinese 1.5A / h. The circuit is standard, from the datasheet, boost converter.
The printed circuit board turned out to be small, only 2 * 2.5 cm. You can do less. All parts as planned - SMD. However, finding a ceramic SMD capacitor with a capacitance of less than 1nF turned out to be not so easy, I had to put an output one. It also turned out to be difficult to find a relatively small inductor of the required inductance, which is not included in saturation at the desired current. As a result, it was decided to use an increased frequency - about 100 kHz and a 47 μH inductor. As a result, it is only a third beyond the dimensions of the board.
The voltage divider for stabilizing 5 volts was successfully obtained from 3 and 1 kΩ resistors. If you try, you can carefully solder a multi-turn potentiometer in their place, as we did in the converter on the NCP3063, in order to be able to adjust the voltage.
The scope of this circuit is not limited to the power supply of devices. It can be successfully used in homemade flashlights, chargers, power banks, in a word, wherever you want to convert one voltage value to another. This microcircuit is not very powerful, but it is able to cope with most applications.
However, when using pulse converters to power measuring instruments and sensitive equipment, one should be aware of the noise level that they create in power circuits. It is believed that for circuits that are very sensitive to such things, the solution is only to use a linear stabilizer between the converter and the circuit directly fed by it. In our case, we obtained the minimum ripple level using the maximum capacitance of the capacitor at the output of the converter, which we could find. It turned out to be tantalum at 220uF. There is room on the board to install several ceramic capacitors at the output, if necessary.
The 3.6 - 5 volt boost converter on the MC34063 showed good stable performance and can be recommended for use.
Not everyone has heard that AA lithium-ion batteries have not only the standard 3.7 volts, but there are models that give the usual one and a half, as in nickel-cadmium batteries. Yes, the very chemistry of the jars does not allow you to create 1.5-volt cells, so there is a step-down regulator inside. Thus, a classic rechargeable battery is obtained, at a standard voltage for most devices and, most importantly, toys. These batteries have the advantage that they charge very quickly and are more powerful in capacity. Therefore, we can safely assume the growth in popularity of such batteries. Let's examine the test sample and analyze its filling.
The battery itself looks like normal AA cells except for the top positive terminal. There is a recessed ring on top around it, which provides a direct connection to the Li-ion cell for .
After tearing off the label, we were faced with a simple steel case. Wanting to disassemble the cell with minimal risk of a short circuit inside, a small pipe cutter was used to carefully disassemble the weld.
The printed circuit board, which gives out 3.7 - 1.5 volts, is located inside the cover.
This converter uses a 1.5MHz DC-DC inverter to provide 1.5V output. Judging by the datasheet, this is a fully integrated converter with all power semiconductor components. The converter is designed for 2.5-5.5 volt input, that is, within the operating range of the Li-ion cell. In addition, it has its own current consumption of only 20 microamps.
The battery has a protection circuit located on a flexible board that surrounds the Li-ion cell. It uses the XB3633A chip, which, like the inverter, is a fully integrated device; there are no external MOSFETs to disconnect the cell from the rest of the circuit. In general, with all this related electronics, an ordinary full-fledged 1.5 V battery was obtained from a lithium cell.
To power electrical appliances, it is necessary to ensure the nominal values of the power supply parameters stated in their documentation. Of course, most modern electrical appliances operate on 220 Volt AC, but it happens that you need to provide power to devices for other countries where the voltage is different or to power something from the car's on-board network. In this article, we will look at how to increase the voltage of DC and AC and what is needed for this.
AC voltage boost
There are two ways to increase the alternating voltage - use a transformer or an autotransformer. The main difference between them is that when using a transformer there is a galvanic isolation between the primary and secondary circuits, but when using an autotransformer it is not.
Interesting! Galvanic isolation is the absence of electrical contact between the primary (input) circuit and the secondary (output) circuit.
Consider frequently asked questions. If you are outside the borders of our vast country and the power grids there are different from our 220 V, for example, 110 V, then in order to raise the voltage from 110 to 220 Volts, you need to use a transformer, for example, such as shown in the figure below:
It should be said that such transformers can be used "in any direction". That is, if the technical documentation of your transformer says “the voltage of the primary winding is 220V, the secondary is 110V” - this does not mean that it cannot be connected to 110V. The transformers are reversible, and if the same 110V is applied to the secondary winding, 220V or another increased value proportional to the transformation ratio will appear on the primary.
The next problem that many people face is, this is especially often observed in private homes and garages. The problem is related to the poor condition and overload of power lines. To solve this problem - you can use LATR (laboratory autotransformer). Most modern models can both lower and smoothly increase network parameters.
Its diagram is shown on the front panel, and we will not dwell on explanations of the principle of operation. LATRs are sold in different capacities, the one in the figure is approximately 250-500 VA (volt-amperes). In practice, there are models up to several kilowatts. This method is suitable for supplying a nominal 220 volts to a specific electrical appliance.
If you need to cheaply boost the voltage throughout the house, your choice is a relay stabilizer. They are also sold in different capacities and the range is suitable for most typical applications (3-15 kW). The device is also based on an autotransformer. About that, we told in the article to which we referred.
DC circuits
Everyone knows that transformers do not work on direct current, while in such cases how to increase the voltage? In most cases, the constant is increased using a field-effect or bipolar transistor and a PWM controller. In other words, it is called a transformerless voltage converter. If these three main elements are connected as shown in the figure below and a PWM signal is applied to the base of the transistor, then its output voltage will increase by Ku times.
Ku=1/(1-D)
We will also consider typical situations.
Let's say you want to make the keyboard backlight using a small piece of LED strip. For this, the charger power from a smartphone (5-15 W) is quite enough, but the problem is that its output voltage is 5 Volts, and common types of LED strips operate from 12 V.
Then how to increase the voltage on the charger? The easiest way to boost is with a device such as a "dc-dc boost converter" or a "switching DC boost converter".
Such devices allow you to increase the voltage from 5 to 12 volts, and are sold both with a fixed value and adjustable, which in most cases will allow you to raise from 12 to 24 and even up to 36 volts. But keep in mind that the output current is limited by the weakest element of the circuit, in the situation under discussion - the current on the charger.
When using the specified board, the output current will be less than the input as many times as the output voltage has risen, without taking into account the efficiency of the converter (it is in the region of 80-95%).
Such devices are built on the basis of MT3608, LM2577, XL6009 microcircuits. With their help, you can make a device for checking the regulator relay not on the car's generator, but on the desktop, adjusting the values \u200b\u200bfrom 12 to 14 Volts. Below you can see a video test of such a device.
Interesting! Homemade lovers often ask the question “how to increase the voltage from 3.7 V to 5 V to make a Power bank on lithium batteries with your own hands?”. The answer is simple - use the FP6291 converter board.
On such boards, using silk-screen printing, the purpose of the pads for connection is indicated, so you do not need a diagram.
Also, a frequently occurring situation is the need to connect a device to a 220V car battery, and it happens that outside the city it is very necessary to get 220V. If you do not have a gasoline generator, use a car battery and an inverter to increase the voltage from 12 to 220 volts. A 1kW model can be bought for $35 and is an inexpensive and proven way to hook up a 220V drill, grinder, boiler, or refrigerator to a 12V battery.
If you are a truck driver, the above inverter will not suit you, due to the fact that your on-board network is most likely 24 volts. If you need to raise the voltage from 24V to 220V, then pay attention to this when buying an inverter.
Although it is worth noting that there are universal converters that can work from both 12 and 24 volts.
In cases where you need to get a high voltage, for example, to raise from 220 to 1000V, you can use a special multiplier. Its typical diagram is shown below. It consists of diodes and capacitors. You will get a constant current output, keep this in mind. This is the Latour-Delon-Grenachere doubler:
And this is how the circuit of an asymmetric multiplier (Cockcroft-Walton) looks like.
With it, you can increase the voltage as many times as you need. This device is built in cascades, the number of which determines how many volts you get at the output. The following video describes how the multiplier works.
In addition to these circuits, there are many others, below are the circuits of a quarter, 6- and 8-fold multipliers, which are used to increase the voltage:
In conclusion, I would like to remind you about safety precautions. When connecting transformers, autotransformers, as well as working with inverters and multipliers, be careful. Do not touch live parts with bare hands. Connections should be made with the device powered off and should not be operated in damp areas where water or splashing may occur. Also, do not exceed the current of the transformer, converter or power supply declared by the manufacturer, if you do not want it to burn out. We hope that the tips provided will help you increase the voltage to the desired value! If you have any questions, ask them in the comments below the article!
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I present an overview of a micropower voltage converter, which is of little use.
Assembled pretty well, compact size 34x15x10mm 
Declared:
Input voltage: 0.9-5V
With one AA battery output current up to 200mA
With two AA batteries output current 500 ~ 600mA
Efficiency up to 96%
Real converter circuit 
A very small capacitance of the input capacitor immediately catches the eye - only 0.15 microfarads. Usually they put it more than 100 times, apparently they naively count on the low internal resistance of the batteries :) Well, they put this one and God bless it, if necessary, you can change it - you immediately set 10 microfarads for yourself. Below in the photo is a native capacitor. 
The throttle dimensions are also very small, which makes you think about the veracity of the declared characteristics.
A red LED is connected to the input of the converter, which starts to glow when the input voltage is more than 1.8V
Tested for the following stabilized input voltages:
1.25V - Ni-Cd and Ni-MH battery voltage
1.5V - voltage of one galvanic cell
3.0V - voltage of two galvanic cells
3.7V - Li-Ion battery voltage
At the same time, I loaded the converter until the voltage dropped to a reasonable 4.66V
Open circuit voltage 5.02V
- 0.70V - the minimum voltage at which the converter starts to idle. At the same time, the LED naturally does not glow - there is not enough voltage.
- 1.25V no-load current 0.025mA, the maximum output current is only 60mA at a voltage of 4.66V. The input current is 330mA, the efficiency is about 68%. The LED at this voltage naturally does not glow. 
- 1.5V no-load current 0.018mA, maximum output current 90mA at 4.66V. The input current is 360mA, the efficiency is about 77%. The LED does not light up at this voltage. 
- 3.0V no-load current 1.2mA (consumes mainly LED), maximum output current 220mA at 4.66V. The input current is 465mA, the efficiency is about 74%. The LED at this voltage glows normally. 
- 3.7V no-load current 1.9mA (consumes mainly LED), maximum output current 480mA at 4.66V. The input current is 840mA, the efficiency is about 72%. The LED at this voltage glows normally. The converter starts to heat up slightly. 
For clarity, I summarized the results in a table. 
Additionally, at an input voltage of 3.7V, I checked the dependence of the conversion efficiency on the load current
50mA - efficiency 85%
100mA - efficiency 83%
150mA - efficiency 82%
200mA - efficiency 80%
300mA - efficiency 75%
480mA - efficiency 72%
As you can see, the lower the load, the higher the efficiency.
Not up to the declared 96%
Ripple output voltage at a load of 0.2A 
Output voltage ripple at a load of 0.48A 
As it is easy to see, at the maximum current, the ripple amplitude is very large and exceeds 0.4V.
Most likely this is due to the output capacitor of a small capacitance with high ESR (measured 1.74 ohms)
Working conversion frequency about 80kHz
I additionally soldered 20 uF ceramics to the output of the converter and received a 5-fold reduction in ripple at maximum current! 
Conclusion: the converter is very low-power - this must be taken into account when choosing it to power your devices
With this voltage converter, you can get 220 volts from a battery with a voltage of 3.7 volts. The circuit is not complicated and all the details are accessible, these converters can power an energy-saving or LED lamp. Unfortunately, more powerful devices cannot be connected, since the converter is low-power and cannot withstand heavy loads.
So, to assemble the converter, we need:
- Transformer from an old phone charger.
- Transistor 882P or its domestic counterparts KT815, KT817.
- Diode IN5398, an analogue of KD226, or in general any other designed for reverse current up to 10 volts of medium or high power.
- Resistor (resistance) at 1 kOhm.
- Bread board.
Naturally, you will also need a soldering iron with solder and flux, wire cutters, wires and a multimeter (tester). Of course, you can also make a printed circuit board, but for a circuit of several parts, you should not spend time developing the layout of the tracks, drawing them and etching the foil textolite or getinaks. We check the transformer. Old charger board.
Carefully unsolder the transformer.
Next, we need to check the transformer and find the conclusions of its windings. We take a multimeter, switch it to ohmmeter mode. We check all the conclusions in turn, find those that “ring” in pairs and write down their resistances.
1. First 0.7 ohm.
2. The second is 1.3 ohms.
3. Third 6.2 ohm.
The winding with the highest resistance was primary, 220 V was supplied to it. In our device, it will be secondary, that is, the output. The rest were relieved of low voltage. With us, they will serve as the primary (the one with a resistance of 0.7 ohms) and part of the generator (with a resistance of 1.3). The results of measurements for different transformers may differ, you need to focus on their relationship to each other.
Device diagram
As you can see it is the simplest. For convenience, we marked the resistance of the windings. A transformer cannot convert direct current. Therefore, a generator is assembled on the transistor and one of its windings. It supplies a pulsating voltage from the input (battery) to the primary winding, a voltage of about 220 volts is removed from the secondary.
We assemble the converter
We take a breadboard.
We install a transformer on it. We choose a resistor of 1 kilo-ohm. We insert it into the holes of the board, next to the transformer. We bend the leads of the resistor so as to connect them to the corresponding contacts of the transformer. We solder it. At the same time, it is convenient to fix the board in any clamp, as in the photo, so that there is no problem of the missing “third hand”. soldered resistor. We bite off the excess length of the output. Board with bitten resistor leads. Next we take the transistor. We install it on the board on the other side of the transformer, as in the screenshot (I chose the location of the parts so that it would be more convenient to connect them according to the circuit diagram). Bend the transistor leads. We solder them. Installed transistor. We take a diode. We install it on the board in parallel with the transistor. We solder. Our scheme is ready.
Solder the wires to connect the DC voltage (DC input). And wires for picking up pulsating high voltage (AC output).
For convenience, we take wires for 220 volts with crocodiles.
Our device is ready.
Testing the Converter
In order to apply voltage, we select a 3-4 volt battery. Although you can use any other power source.
Solder the low voltage input wires to it, observing the polarity. We measure the voltage at the output of our device. It turns out 215 volts.
Attention. It is not advisable to touch the parts when the power is connected. This is not so dangerous if you do not have health problems, especially with the heart (although two hundred volts, but the current is weak), but it can be unpleasant to “pinch”.
We complete the test by connecting a fluorescent energy-saving lamp for 220 volts. Thanks to the "crocodiles" this is easy to do without a soldering iron. As you can see, the lamp is on.
Our device is ready.
Advice. You can increase the power of the converter by installing a transistor on a radiator.
True, the battery capacity will not last long. If you are going to use the converter all the time, then choose a larger battery and make a case for it.