Switching power supply for umzch on ir2161. Switching power supply for ir2153, ir2155 Switching power supply for 2161 840

This article focuses on the 2161 Second Edition (SE) series of switching power supplies based on the IR2161 controller.

Here we will talk about three finished SMPS based on IR2161, each of which will be better than the previous one, their circuits, printed circuit boards and some important points will be described.

But before starting the story directly about the power supplies themselves, I would like to dwell on the IR2161 itself and describe in detail the principle and features of its operation. As time has shown, even those who assemble their own impulse blocks for 2161 have a poor idea of ​​\u200b\u200bhow this microcircuit works (china +, hello). It is for this reason that you can meet a lot of elementary questions that could easily be answered in the datasheet, but apparently not everyone is able to understand the material presented there, and many are simply too lazy to delve into it.

IR2161 is a specialized intellectual integrated circuit half-bridge converter for halogen lamps (electronic transformer). Remember Toshibra electronic transformers? It is for such "electronic transformers" that this controller was developed, but not for those cheap Chinese fakes like Toshibra, but for good and high-quality electronic transformers that have nothing to do with the depicted Toshibra.

The IR2161 controller includes all the necessary protections, and also allows you to adapt the converter for dimming with a standard phase control dimming (the possibility of dimming for our purposes does not matter). There is also an output voltage compensation depending on the power consumed by the load. IR2161 has adaptive dead time which improves stability and frequency modulation "dither" to reduce electromagnetic radiation(AMY). All of this is integrated into a small 8-pin DIP or SOIC package to keep the size of the SMPS as small as possible.

I will briefly list features IR2161 listed in the datasheet:

• Defence from short circuit and overload;
• Auto reset short circuit protection;
• Frequency modulation "dither" (to reduce EMP);
• Microcurrent start (for the initial start of the controller, a current of not more than 300 μA is sufficient);
• Possibility of dimming (but we are not interested);
• Output voltage compensation (a kind of voltage stabilization);
• Soft start;
• Adaptive dead time ADT;
• Compact body;
• Produced using lead-free technology (Leed-Free).

Here are some important ones for us specifications:

Maximum Sink/Sink Current: ±500mA
A sufficiently large current allows you to control powerful keys and build quite powerful switching power supplies on the basis of this controller without the use of additional drivers;

Maximum current consumed by the controller: 10mA
Focusing on this value, the power circuits of the microcircuit are designed;

Minimum operating voltage of the controller: 10.5V
At a lower value of the supply voltage, the controller switches to UVLO mode and the oscillation stops;

Minimum stabilization voltage of the Zener diode built into the controller: 14.5V
The external zener diode must have a stabilization voltage not higher than this value in order to avoid damage to the microcircuit due to shunting excess current to the COM pin;

CS pin voltage for overload protection: 0.5V
The minimum voltage at the CS pin at which the overload protection trips;

Voltage at the CS pin for short-circuit protection operation: 1V
The minimum voltage at the CS pin at which the short-circuit protection is triggered;

Operating frequency range: 34 - 70kHz
The operating frequency is not directly set and depends only on the power consumed by the load;

Dead time default: 1µs
It is used when it is impossible to work in the adaptive dead time (ADT) mode, as well as when there is no load;

Soft start frequency: 130kHz
The frequency at which the controller operates in soft start mode;

The main attention should now be paid to what modes of operation of the microcircuit exist and in what sequence they are located relative to each other. I will focus on describing the principle of operation of each of the blocks of the circuit, and I will describe the sequence of their operation and the conditions for the transition from one mode to another more briefly. I'll start by describing each of the circuit blocks:

Under-voltage Lock-Out Mode (UVLO)- the mode in which the controller is when its supply voltage is below the minimum threshold value (approximately 10.5V).

Soft Start Mode, soft start mode- operating mode, in which the oscillator of the controller operates at an increased frequency for a short time. When the oscillator is turned on, the frequency of its operation is initially very high (about 130 kHz). This leads to output voltage converter will be lower because the power supply transformer has a fixed inductance which will have a higher impedance at higher frequency and thus reduce the primary voltage. Reduced voltage will naturally result in reduced current in the load. As the CSD capacitor charges from 0 to 5V, the oscillation frequency will gradually decrease from 130 kHz to the operating frequency. The duration of the soft start sweep will depend on the capacitance value of the CSD capacitor. However, since the CSD capacitor also sets the trip delay time and participates in the operation of the voltage compensation unit, its capacitance must be strictly 100nF.

Softstart problem. I would like to be completely honest and mention the fact that if there are large-capacity filter capacitors at the output of the power supply, the soft start most often does not work and the SMPS starts immediately at the operating frequency bypassing the soft start mode. This happens due to the fact that at the moment of start, the discharged capacitors in the secondary circuit have a very low self-resistance and a very high current is required to charge them. This current causes a short-term operation of the short-circuit protection, after which the controller immediately restarts and enters the RUN mode, bypassing the soft start mode. You can fight this by increasing the inductance of the chokes in the secondary circuit, which are located immediately after the rectifier. Inductors with a large inductance stretch the process of charging the output filter capacitors, in other words, the capacitors are charged with a smaller current, but longer in time. Less charging current does not trigger the protection at startup and allows the soft start to perform its functions normally. Just in case, regarding this issue, I contacted the technical support of the manufacturer, to which I received an answer:

"A typical halogen converter has an AC output with no rectifier or output capacitors. Soft start works by reducing the frequency. To ensure soft start the transformer must have significant leakage. However, it should be possible in your case. Try placing the inductor on the secondary side from the bridge diodes to the capacitor.

Best wishes.
Infineon Technologies
Steve Rhyme, Support Engineer"

My assumptions about the cause of the uncertain work of the soft start turned out to be correct, and moreover, they even offered me the same way to deal with this problem. And again, to be completely honest, it should be added that the use of coils with increased inductance, relative to those usually used at the output of the SMPS, improves the situation, but does not completely eliminate the problem. However, this problem can be tolerated given that there is a thermistor at the input of the SMPS, which limits the inrush current.

Run Mode, operating mode. When the soft start is completed, the system enters the voltage compensated operating mode. This function provides some stabilization of the converter output voltage. Voltage compensation occurs due to a change in the operating frequency of the converter (increasing the frequency - reduces the output voltage), although the accuracy of this type of "stabilization" is not high, it is non-linear and depends on many parameters and, therefore, is not easily predictable. IR2161 controls the load current through the current resistor (RCS). The peak current is detected and amplified in the controller and then applied to the CSD pin. The voltage across the CSD capacitor, in operating mode (voltage compensation mode), will vary from 0 (at minimum load) to 5V (at maximum load). In this case, the generator frequency will vary from 34 kHz (Vcsd = 5V) to 70 kHz (Vcsd = 0V).

It is also possible to attach feedback to the IR2161, which will allow you to organize almost complete stabilization of the output voltage and will allow you to track and maintain the required voltage at the output much more accurately:

We will not consider this scheme in detail in this article.

Shut Down Mode The IR2161 contains a two-position automatic shutdown system that detects both a short circuit and an inverter overload condition. The voltage at the CS pin is used to determine these conditions. If the output of the converter is shorted, a very large current will flow through the switches and the system must shut down for several periods of time on the mains, otherwise the transistors will be quickly destroyed due to thermal breakdown of the junction. The CS pin has a turn-off delay to prevent false tripping, either due to inrush current at turn-on or transient currents. Lower threshold (when Vcs > 0.5< 1 В), имеет намного big delay until the IIP is turned off. The delay for overload trip is approximately 0.5 sec. Both shutdown modes (overload and short circuit) are automatically reset, which allows the controller to resume operation approximately 1 second after the overload or short circuit is removed. This means that if the fault is corrected, the inverter can continue to operate normally. The oscillator operates at the minimum operating frequency (34 kHz) when the CSD capacitor is switched to the trip circuit. In soft start or run mode, if the overload threshold (Vcs > 0.5V) is exceeded, the IR2161 quickly charges the CSD to 5V. When the voltage on the CS pin is greater than 0.5V and when the 1V short circuit threshold is exceeded, the CSD will charge from 5V to the controller supply voltage (10-15V) in 50ms. When the overload threshold voltage Vcs is greater than 0.5V but less than 1V, the CSD is charged from 5V to the supply voltage in approximately 0.5 sec. It should be remembered and taken into account the fact that high-frequency pulses appear at the CS pin with a 50% duty cycle and a sinusoidal envelope - this means that only at the peak of the mains voltage, the CSD capacitor will charge in stages, in each half-cycle. When the voltage across the CSD capacitor reaches the supply voltage, the CSD is discharged to 2.4V and the converter starts up again. If the fault is still present, the CSD starts charging again. If the fault disappears, the CSD will discharge to 2.4V, and then the system will automatically return to the voltage compensation operating mode.

STANDBY mode- the mode in which the controller is in case of insufficient supply voltage, while it consumes no more than 300 μA. In this case, the oscillator, of course, is turned off and the SMPS does not work, there is no voltage at its output.

Blocks Fault Timing Mode, Delay and Fault Mode, although they are shown in the block diagram, they are not, in fact, the operating modes of the controller; rather, they can be attributed to transitional stages (Delay and Fault Mode) or transition conditions from one mode to another (Fault Timing Mode).

And now I will describe how it all works together:
When power is applied, the controller starts in UVLO mode. As soon as the controller supply voltage exceeds the minimum voltage value required for stable operation, the controller switches to soft start mode, the oscillator starts at a frequency of 130 kHz. The CSD capacitor is smoothly charged up to 5V. As the external capacitor charges, the frequency of the oscillator is reduced to the operating frequency. Thus, the controller enters the RUN mode. As soon as the controller enters RUN mode, the CSD capacitor instantly discharges to ground potential and is connected internally to the voltage compensation circuit. If the SMPS starts not at idle, but under load, there will be a potential at the CS pin proportional to the load value, which through the internal circuits of the controller will act on the voltage compensation unit and will not allow the CSD capacitor to completely discharge after the soft start is completed. Due to this, the launch will occur not at the maximum frequency of the operating range, but at a frequency corresponding to the load value at the output of the SMPS. After switching to RUN mode, the controller works according to the situation: either it remains to work in this mode until you get bored and you turn off the power supply from the outlet, or ... In case of overheating, the controller switches to FAULT mode, the oscillator stops working . After the chip cools down, it restarts. In the event of an overload or short circuit, the controller goes into Fault Timing mode, while the external CSD capacitor is instantly disconnected from the voltage compensation node and connected to the trip node (the CSD capacitor in this case sets the controller shutdown delay time). The frequency of operation is instantly reduced to the minimum. In the event of an overload (when the voltage at the CS pin > 0.5< 1 В), контроллер переходит в режим SHUTDOWN и выключается, но происходит это не мгновенно, а только в том случае, если перегрузка продолжается дольше половины секунды. Если перегрузки носят импульсный характер с продолжительностью импульса не более 0,5 сек, то контроллер будет просто работать на минимально возможно частоте, постоянно переключаясь между режимами RUN, Fault Timing, Delay, RUN (при этом будут отчетливо слышны щелчки). Когда напряжение на выводе CS превышает 1В, срабатывает защита от короткого замыкания. При устранении перегрузки или короткого замыкания, контроллер переходит в режим STANDBY и при наличии благоприятных условий для перезапуска, минуя режим софт-старта, переходит в режим RUN.

Now that you understand how the IR2161 works (I hope so), I will tell you about the switching power supplies themselves based on it. I want to immediately warn you that if you decide to assemble a switching power supply based on this controller, then you should assemble the SMPS guided by the latest, most advanced circuit on the corresponding printed circuit board. Therefore, the list of radio elements at the bottom of the article will be given only for latest version power supply. All intermediate editions of the SMPS are shown only to demonstrate the process of improving the device.

And the first IIP that will be discussed is conditionally named by me 2161 SE 2.

The main and key difference between 2161 SE 2 and the SMPS described in the first article is the presence of a self-powered controller circuit, which made it possible to get rid of boiling quenching resistors and, accordingly, increase efficiency by several percent. Other equally significant improvements have also been made: optimized PCB layout, added more output terminals for connecting the load, added a varistor.

The IIP scheme is shown in the image below:

The self-feeding circuit is built on VD1, VD2, VD3 and C8. Due to the fact that the self-supply circuit is connected not to a low-frequency network of 220V (with a frequency of 50 Hz), but to the primary winding of a high-frequency transformer, the self-supply quenching capacitor (C8) is only 330pF. If self-supply was organized from a 50Hz low-frequency network, then the capacitance of the quenching capacitor would have to be increased by a factor of 1000, it goes without saying that such a capacitor would take up much more space on the printed circuit board. The described self-feeding method is no less effective than self-feeding from a separate transformer winding, but it is much simpler. The VD1 zener diode is necessary to facilitate the operation of the built-in zener diode of the controller, which is not capable of dissipating significant power and can simply be broken without installing an external zener diode, which will lead to a complete loss of microcircuit performance. The stabilization voltage VD1 should be in the range of 12 - 14V and should not exceed the stabilization voltage of the controller's built-in zener diode, which is approximately 14.5V. As VD1, you can use a zener diode with a stabilization voltage of 13V (for example, 1N4743 or BZX55-C13), or use several zener diodes connected in series, which I did. I switched on two zener diodes in series: one of them at 8.2V, the other at 5.1V, which ultimately gave a resulting voltage of 13.3V. With this approach to powering the IR2161, the controller supply voltage does not sag and practically does not depend on the magnitude of the load connected to the SMPS output. In this circuit, R1 is only needed to start the controller, so to speak, for the initial kick. The R1 gets a little warm, but not nearly as hot as it was in the first version of this power supply. Using a high-resistance resistor R1 gives another interesting feature: the voltage at the output of the SMPS does not appear immediately after being connected to the network, but after 1-2 seconds, when C3 is charged to the minimum voltage of the appetizer 2161 (approximately 10.5V).

Starting from this SMPS and in all subsequent ones, a varistor is used at the SMPS input, it is designed to protect the SMPS from exceeding the input voltage above the allowable value (in this case, 275V), and also very effectively suppresses high-voltage interference without letting them into the SMPS input from network and without releasing interference from the SMPS back into the network.

In the rectifier of the secondary power supply of the power supply, I used SF54 diodes (200V, 5A), two in parallel. The diodes are located in two floors, the diode leads should be as long as possible - this is necessary for better heat dissipation (the leads are a kind of radiator for the diode) and better air circulation around the diodes.

The transformer in my case is made on a core from a computer power supply - ER35/21/11. The primary winding has 46 turns in three 0.5 mm wires, two secondary windings of 12 turns in three 0.5 mm wires. The input and output chokes are also taken from a computer PSU.

The described power supply for a long time (without limitation on operating time), is capable of delivering 250W to the load, for a short time (no more than a minute) - 350W. When using this SMPS in dynamic load mode (for example, to power an audio frequency power amplifier of class B or AB), it is possible to power an UMZCH with a total output power of 300W (2x150W in stereo mode) from this switching power supply.

Oscillogram on the primary winding of the transformer (without snubber, R5 = 0.15 ohm, 190W at the output):

As can be seen from the waveform, with an output power of 190W, the frequency of the SMPS operation is reduced to 38kHz, at idle, the SMPS operates at a frequency of 78kHz:

From the oscillograms, in addition, it is clearly seen that there are no outliers on the graph, and this undoubtedly positively characterizes this SMPS.

At the output of the power supply, in one of the arms, you can observe the following picture:

The ripples have a frequency of 100 Hz and a ripple voltage of approximately 0.7 V, which is comparable to the ripples at the output of a classic, linear, unstabilized power supply. For comparison, here is an oscillogram taken while working at the same output power for a classic power supply (15000 uF capacitors in the arm):

As can be seen from the waveforms, the supply voltage ripple at the output of a switching power supply is lower than that of a classic power supply of the same power (0.7V for an SMPS, versus 1V for a classic power supply). But unlike a classic power supply, a small high-frequency noise is noticeable at the output of the SMPS. However, there are no significant high-frequency interference or emissions. The ripple frequency of the supply voltage at the output is 100Hz and it is due to the voltage ripple in the primary circuit of the SMPS on the +310V bus. To further reduce the ripple at the output of the SMPS, it is necessary to increase the capacitance of the capacitor C9 in the primary circuit of the power supply or the capacitance of the capacitors in the secondary circuit of the power supply (the first is more effective), and to reduce high-frequency interference, use chokes with a higher inductance at the output of the SMPS.

The printed circuit board looks like this:

The next IIP scheme that will be discussed is - 2161 SE 3:

In finished form, the power supply assembled according to this scheme looks like this:

In the scheme fundamental differences from SE 2 - no, the differences are mainly related to the printed circuit board. In the circuit, only snubbers were added in the secondary windings of the transformer - R7, C22 and R8, C23. Gate resistor values ​​have been increased from 22Ω to 51Ω. Reduced value of capacitor C4 from 220uF to 47uF. Resistor R1 is assembled from four 0.5W resistors, which made it possible to reduce the heating of this resistor and slightly reduce the cost of the design. in my area, four half-watt resistors are cheaper than one two-watt one. But the ability to install one two-watt resistor remained. In addition, the value of the self-feeding capacitor was increased to 470pF, there was not much point in this, but it was done as an experiment, the flight was normal. MUR1560 diodes in the TO-220 package were used as rectifier diodes in the secondary circuit. Optimized and reduced circuit board. The dimensions of the SE 2 printed circuit board are 153x88, while the SE 3 printed circuit board has dimensions of 134x88. The printed circuit board looks like this:

The transformer is made on a core from a computer power supply - ER35/21/11. The primary winding has 45 turns in three 0.5 mm wires, two secondary windings of 12 turns in four 0.5 mm wires. The input and output chokes are also taken from a computer PSU.

The very first inclusion of this SMPS in the network showed that the snubbers in the secondary circuit of the power supply are clearly superfluous, they were immediately soldered and were not used further. Later, the snubber of the primary winding was also soldered, as it turned out, it did much more harm than good.

From this power supply for a long time it was possible to remove the power of 300-350W, for a short time (no more than a minute) this SMPS can output up to 500W, after a minute of operation in this mode, the common radiator heats up to 60 degrees.

Look at the waveforms:

Everything is still beautiful, the rectangle is almost perfectly rectangular, there are no outliers. With snubbers, oddly enough, everything was not so beautiful.

The following scheme is final and most perfect 2161 SE 4:

In the assembled form, the device according to this scheme looks like this:

Like last time, there were no major changes in the scheme. Perhaps the most noticeable difference is that snubbers have disappeared, both in the primary circuit and in the secondary ones. Because, as my experiments have shown, due to the peculiarities of the IR2161 controller, snubbers only interfere with its operation and are simply contraindicated. Other changes were also made. Reduced values ​​of gate resistors (R3 and R4) from 51 to 33 ohms. In series with the self-powered capacitor C7, a resistor R2 is added to protect against overcurrent when charging capacitors C3 and C4. Resistor R1 still consists of four half-watt resistors, and resistor R6 is now hidden under the board and consists of three 2512 format SMD resistors. The required resistance is gained with three resistors, but it is not necessary to use exactly three resistors, depending on the required power, you can use one, two or three resistors is acceptable. The RT1 thermistor has been moved from the SMPS exit to the +310V target. The remaining measurements relate only to the layout of the printed circuit board and it looks like this:

On the printed circuit board, a safety gap has been added between the primary and secondary circuits, in the narrowest place a through cut has been made in the board.

The transformer is exactly the same as in the previous power supply: it is made on a core from a computer power supply - ER35/21/11. The primary winding has 45 turns in three 0.5 mm wires, two secondary windings of 12 turns in four 0.5 mm wires. The input and output chokes are also taken from a computer PSU.

The output power of the power supply remained the same - 300-350W in long-term mode and 500W in short-term mode (no more than a minute). From this SMPS it is possible to power the UMZCH with a total output power of up to 400W (2x200W in stereo mode).

Now let's look at the waveforms on the primary winding of the transformer of this switching power supply:

As before, everything is beautiful: the rectangle is rectangular, there are no outliers.

At the output of one of the arms of the power supply, at idle, you can observe the following picture:

As you can see, the output contains a negligible high-frequency noise with a voltage of no more than 8mV (0.008V).

Under load, at the output, we can observe the already well-known ripples with a frequency of 100 Hz:

With an output power of 250W, the ripple voltage at the output of the SMPS is 1.2V, which, given the lower capacitance of the capacitors in the secondary circuit (2000uF in the shoulder, versus 3200uF for SE2) and a large output power at which the measurements were made, looks very good. The high-frequency component at a given output power (250W) is also insignificant, has a more ordered character and does not exceed 0.2V, which is a good result.

Setting the protection threshold. The threshold at which the protection will trip is set by the RCS resistor (R5 - in SE 2, R6 - in SE 3 and SE 4).

This resistor can be either an output resistor or a 2512 format SMD. The RCS can be made up of several resistors connected in parallel.
The RCS rating is calculated using the formula: Rcs = 32 / Pnom. Where, Pnom is the output power of the SMPS, when exceeded, the overload protection will operate.
Example: let's say that we need the overload protection to work when the output power exceeds 275W. We calculate the resistor value: Rcs=32/275=0.116 Ohm. You can use either one 0.1 ohm resistor, or two 0.22 ohm resistors in parallel (resulting in 0.11 ohms), or three 0.33 ohm resistors in parallel (resulting in 0.11 ohms) .

Now it's time to touch on the most interesting topic of the people - calculation of a transformer for a switching power supply. By your many requests, I will finally tell you in detail how to do this.

First of all, we need a core with a frame, or just a core if it is an annular core (R shape).

Cores and frames can be of completely different configurations, any one can be used. I used an ER35 core from a computer power supply. The most important thing is that the core does not have a gap; cores with a gap cannot be used.

Next, we need a program for calculating the transformer, the Lite-CalcIT program is best suited for these purposes:

By default, immediately after starting the program, you will see similar numbers.
Starting the calculation, the first thing we will do is select the shape and dimensions of the core in the upper right corner of the program window. In my case, the shape is ER, and the dimensions are 35/21/11.

The dimensions of the core can be measured independently, how to do this is easy to understand from the following illustration:

Next, select the core material. Well, if you know what material your core is made of, if not, then it's okay, just choose the default option - N87 Epcos. In our conditions, the choice of material will not have a significant impact on the final result.

The next step is to select the converter circuit, we have it - half-bridge:

In the next part of the program - "supply voltage", select "variable" and indicate 230V in all three windows.

In the part "characteristics of the converter", we indicate the bipolar output voltage we need (voltage of one shoulder) and the required output power of the SMPS, as well as the diameter of the wire with which you want to wind the secondary and primary windings. In addition, the type of rectifier used is selected - "bipolar. with a midpoint". In the same place we put a tick "use the desired diameters" and under "stabilization of outputs" we select - "no". Choose the type of cooling: active with a fan or passive without it. As a result, you should get something like this:

The real values ​​​​of the output voltages will turn out to be more than you specify in the program when calculating. In this case, with a voltage of 2x45V specified in the program, the output of a real SMPS will be approximately 2x52V, so when calculating, I recommend specifying a voltage less than necessary by 3-5V. Or indicate the required output voltage, but wind one turn less than indicated in the program calculation results. The output power must not exceed 350W (for 2161 SE 4). The diameter of the wire for winding, you can use any that you have available, you need to measure and indicate its diameter. It is not necessary to wind the windings with a wire with a diameter of more than 0.8 mm, it is better to wind the windings using several (two, three or more) thin wires than one thick wire.

After all this, click on the "calculate" button and get the result, in my case it turned out the following:

We focus on the points highlighted in red. The primary winding in my case will consist of 41 turns wound in two wires with a diameter of 0.5 mm each. The secondary winding consists of two halves of 14 turns, wound in three wires with a diameter of 0.5 mm each.

After receiving all the necessary calculated data, we proceed directly to the winding of the transformer.
Here, it seems to me, there is nothing complicated. I'll tell you how I do it. First, the entire primary winding is wound. One of the ends of the wire (s) is stripped and soldered to the corresponding terminal of the transformer frame. Then the winding starts. The first layer is wound, after which a thin layer of insulation is applied. After that, the second layer is wound and a thin layer of insulation is again applied and thus the entire required number of turns of the primary winding is wound. It is best to wind the windings turn to turn, but it can also be obliquely crooked or just "anyhow", this will not play a noticeable role. After the required number of turns has been wound, the end of the wire(s) is cut off, the end of the wire is stripped and soldered to the other appropriate terminal of the transformer. After winding the primary winding, a thick layer of insulation is applied to it. As insulation, it is best to use a special lavsan tape:

The windings of pulse transformers of computer power supplies are insulated with the same tape. This tape conducts heat well and has high temperature resistance. From improvised materials, it can be advised to use: FUM tape, masking tape, paper band-aid or a baking sleeve cut into long strips. It is absolutely impossible to use for insulation of PVC windings and cloth electrical tape, stationery tape, cloth plaster.

After the primary winding is wound and insulated, we proceed to the winding of the secondary winding. Some people wind two halves of the winding at the same time, and then separate them, but I wind the halves of the secondary winding in turn. The secondary winding is wound in the same way as the primary. First, we clean and solder one end of the wire (wires) to the corresponding terminal of the transformer frame, wind the required number of turns, applying insulation after each layer. Having wound the required number of turns of one half of the secondary winding, we clean and solder the end of the wire to the corresponding terminal of the frame and apply a thin layer of insulation. We solder the beginning of the wire of the next half of the winding to the same terminal as the end of the previous half of the winding. We wind in the same direction, the same number of turns as the previous half of the winding, applying insulation after each layer. Having wound the required number of turns, solder the end of the wire to the corresponding terminal of the frame and apply a thin layer of insulation. It is not necessary to apply a thick layer of insulation after winding the secondary winding. On this winding can be considered finished.

After winding is completed, it is necessary to insert the core into the frame and glue the halves of the core. For gluing, I use a second super glue. The layer of glue should be minimal so as not to create a gap between the parts of the core. If you have a ring core (R shape), then naturally you won’t have to glue anything, but the winding process will be less convenient, it will take more strength and nerves. In addition, the ring core is less convenient due to the fact that you will have to create and form the transformer leads yourself, as well as think over the fastening of the finished transformer to the printed circuit board.

Upon completion of the winding and assembly of the transformer, something like this should turn out:

For the convenience of narration, I will add the SMPS 2161 SE 4 diagram here, in order to briefly tell about the element base and possible replacements.

Let's go in order - from the entrance to the exit. At the input, the mains voltage meets the F1 fuse, the fuse can have a rating from 3.15A to 5A. The RV1 varistor must be rated for 275V, such a varistor will be marked 07K431, but 10K431 or 14K431 variators can also be used. It is also possible to use a varistor with a higher threshold voltage, but the protection and interference suppression efficiency will be noticeably lower. Capacitors C1 and C2 can be either ordinary film (type CL-21 or CBB-21) or noise-suppressing type (for example X2) for a voltage of 275V. We unsolder the dual inductor L1 from a computer power supply or other faulty equipment. The inductor can be made independently by winding 20-30 turns on a small ring core, with a wire with a diameter of 0.5 - 0.8 mm. The VDS1 diode bridge can be any for a current from 6 to 8A, for example, indicated in the diagram - KBU08 (8A) or RS607 (6A). As VD4, any slow or fast diode with a current from 0.1 to 1A and a reverse voltage of at least 400V is suitable. R1 can consist of four half-watt 82kΩ resistors, or it can be one two-watt resistor with the same resistance. Zener diode VD1 must have a stabilization voltage in the range of 13 - 14V, it is allowed to use both one zener diode and serial connection two zener diodes with a lower voltage. C3 and C5 can be both film and ceramic. C4 should have a capacity of no more than 47 microfarads, voltage 16-25V. Diodes VD2, VD3, VD5 must be very fast, for example - HER108 or SF18. C6 can be either film or ceramic. Capacitor C7 must be rated for a voltage of at least 1000V. C9 can be either film or ceramic. The value of R6 must be calculated for the required output power, as described above. As R6, you can use both SMD resistors of the 2512 format, and output one- or two-watt resistors, in any case, the resistor (s) are installed under the board. Capacitor C8 must be a film capacitor (type CL-21 or CBB-21) and have a permissible operating voltage of at least 400V. C10 is an electrolytic capacitor for a voltage of at least 400V, the value of low-frequency ripples at the output of the SMPS depends on its capacitance. RT1 is a thermistor, you can buy it, or you can solder it from a computer power supply, its resistance should be from 10 to 20 ohms and the allowable current should be at least 3A. As transistors VT1 and VT2, both those indicated in the IRF740 diagram and other transistors with similar parameters, for example, IRF840, 2SK3568, STP10NK60, STP8NK80, 8N60, 10N60, can be used. Capacitors C11 and C13 must be film capacitors (type CL-21 or CBB-21) with allowable voltage not less than 400V, their capacitance should not exceed 0.47 μF indicated in the diagram. C12 and C14 - ceramic, high-voltage capacitors for a voltage of at least 1000V. Diode bridge VDS2 consists of four diodes connected by a bridge. As VDS2 diodes, it is necessary to use very fast and powerful diodes, for example, such as - MUR1520 (15A, 200V), MUR1560 (15A, 600V), MUR820 (8A, 200V), MUR860 (8A, 600V), BYW29 (8A, 200V) , 8ETH06 (8A, 600V), 15ETH06 (15A, 600V). Inductors L2 and L3 are soldered from a computer power supply or made independently. They can be wound both on separate ferrite rods and on a common ring core. Each of the chokes should contain from 5 to 30 turns (more is better), with a wire with a diameter of 1 - 1.5 mm. Capacitors C15, C17, C18, C20 must be film capacitors (type CL-21 or CBB-21) with a permissible voltage of 63V or more, the capacitance can be any, the larger their capacitance is, the better, the stronger the suppression of high-frequency interference. Each of the capacitors labeled C16 and C19 in the diagram consists of two 1000uF 50V electrolytic capacitors. In your case, you may need to use higher voltage capacitors.

And as a final chord, I will show a photo that shows the evolution of the switching power supplies I created. Each next SMPS is smaller, more powerful and better than the previous one:

That's all! Thank you for your attention!

List of radio elements

Do-it-yourself homemade switching power supply.

The author of the design (Sergey Kuznetsov, his website is classd.fromru.com) developed this home-made network power supply
for powering a powerful UMZCH (Audio Frequency Power Amplifier). Benefits of switching power supplies in front of conventional transformer power supplies are obvious:

• The weight of the resulting product is much lower
• The dimensions of the switching power supply are much smaller.
• The efficiency of the product, and, accordingly, the heat dissipation is lower
• The range of supply voltages (voltage surges in the network) at which the power supply can work stably is much wider.

However, making a switching power supply requires much more effort and knowledge than making a conventional low-frequency 50 Hz power supply. The low-frequency power supply consists of a mains transformer, a diode bridge and smoothing filter capacitors, while a pulse power supply has a much more complex structure.

The main disadvantage of switching network power supplies is the presence of high-frequency interference, which will have to be overcome, in case of incorrect tracing of the printed circuit board, or when wrong choice component base. When you turn on the UPS, as a rule, a strong spark is observed in the outlet. This is due to the large peak start-up current of the power supply, due to the charge of the input filter capacitors. To eliminate such current surges, the developers design various “soft start” systems that charge the filter capacitors with a low current in the first phase of operation, and at the end of the charge they organize the supply of the full mains voltage to the UPS. In this case, a simplified version of such a system is used, which is a series-connected resistor and a thermistor that limit the charge current of the capacitors.

The circuit is based on the IR2153 PWM controller in a standard switching circuit. Field-effect transistors IRFI840GLC can be replaced with IRFIBC30G, the author does not recommend installing other transistors, as this will entail the need to reduce the ratings of R2, R3 and, accordingly, to an increase in heat generated. The voltage on the PWM controller must be at least 10 volts. The operation of the microcircuit from a voltage of 11-14 Volts is desirable. Components L1 C13 R8 improve the mode of operation of transistors.

The inductors located at the output of the 10 μg power supply are wound with 1 mm wire on ferrite dumbbells with a magnetic permeability of 600 NN. You can wind on rods from old receivers, 10-15 turns are enough. Capacitors in the power supply should be low-impedance to reduce RF noise.

The transformer was calculated using the Transformer 2 program. The induction should be chosen as small as possible, preferably no more than 0.25. Frequency in the region of 40-80k. The author does not recommend the use of rings of domestic production, in view of the non-identity of the ferrite parameters and significant losses in the transformer. The printed circuit board was designed for a transformer of size 30x19x20. When adjusting the power supply, it is forbidden to connect the ground of the oscilloscope to the connection point of the transistors. It is advisable to start the power supply for the first time with a 220V lamp with a power of 25-40W connected in series with the source, while the UPS cannot be heavily loaded. The printed circuit board of the block in LAY format can be downloaded or

Hello everybody!

Background:

The site has a circuit for audio frequency power amplifiers (ULF) 125, 250, 500, 1000 watts, I chose the 500 watt option, because in addition to radio electronics, I’m also a little fond of music and therefore I wanted something better from ULF. The circuit on the TDA 7293 did not suit me, so I decided to use the 500 watt field effect transistors. From the beginning, I almost assembled one ULF channel, but work stopped for various reasons (time, money, and the unavailability of some components). As a result, I bought the missing components and finished one channel. Also, after a certain time, I collected the second channel, set it all up and tested it on the power supply from another amplifier, everything worked on highest level I liked the quality very much, I did not even expect it to be so. Separate, many thanks to the radio amateurs Boris, AndReas, nissan who have collected it all the time, helped in setting it up and in other nuances. Next up was the power supply. Of course, I would like to make a power supply on a conventional transformer, but again, everything stops at the availability of materials for the transformer and their cost. Therefore, I decided to stop at the UPS after all.

Well, now about the UPS itself:

I used IRFP 460 transistors, because I did not find them indicated on the diagram. I had to put the transistors on the contrary by turning 180 degrees, drill more holes for the legs and solder the wires (see the photo). When I made a printed circuit board, I later only realized that I couldn’t find the transistors I needed as in the diagram, I installed those that were (IRFP 460). Transistors and output rectifier diodes must be installed on the heat sink through insulating heat-conducting gaskets, and radiators must also be cooled with a cooler, otherwise transistors and rectifier diodes may overheat, but the heating of transistors of course also depends on the type of transistors used. The lower the internal resistance of the field worker, the less they will heat up.

Also, I have not yet installed a Varistor of 275 Volts at the input, since it is not in the city and I have it too, but it is expensive to order one part via the Internet. I will have separate electrolytes for the output, because they are not available for the required voltage and the size is not suitable. I decided to put 4 electrolytes of 10,000 microfarads * 50 volts, 2 in series per arm, in total, each arm will have 5000 microfarads * 100 volts, which will be completely enough for the power supply, but it is better to put 10,000 microfarads * 100 volts per arm.

The diagram shows the resistor R5 47 kOhm 2 W for powering the microcircuit, it should be replaced with 30 kOhm 5 W (preferably 10 W) in order for the IR2153 chip to have enough current at a heavy load, otherwise it may go into protection against a lack of current or it will pulsate voltage will affect the quality. In the author's circuit, it costs 47 kOhm, which is a lot for such a power supply unit. By the way, the resistor R5 will get very hot, don't worry, the type of these circuits on IR2151, IR2153, IR2155 for power supply is accompanied by a strong heating of R5.

In my case, I used an ETD 49 ferrite core and it was very hard for me to fit onto the board. At a frequency of 56 kHz, according to calculations, it can give up to 1400 watts at this frequency, which in my case has a margin. You can also use a toroidal or other shape of the core, the main thing is that it would be suitable in terms of overall power, permeability and, of course, that there would be enough space to place it on the board.

Winding data for ETD 49: 1 = 20 turns with 0.63 wire in 5 wires (220 volt winding). 2-ka \u003d main power bipolar 2 * 11 turns with a wire 0.63 in 4 wires (winding 2 * 75-80) volts. 3-ka \u003d 2.5 turns with a wire 0.63 in 1 wire (12 volt winding, for soft start). 4-ka \u003d 2 turns with a wire 0.63 in 1 wire (an additional winding for powering preliminary circuits (tone block, etc.). The transformer frame needs a vertical design, I have a horizontal one, so I had to fence it. It can be wound in a frameless design. On other types you will have to calculate the core yourself, you can use the program that I will leave at the end of the article.In my case, I used a bipolar voltage of 2 * 75-80 volts for a 500-watt amplifier, why less, because the load of the amplifier will not be 8 ohms but 4 ohms.

Setup and first run:

When starting the UPS for the first time, be sure to install a 60-100 watt light bulb in the gap between the network cable and the UPS. When you turn it on, if the light does not light up, then it's already good. At the first start, short circuit protection may turn on and the HL1 LED will light up, since high-capacity electrolytes take a huge current at the moment of switching on, if this happens, then you need to twist the multi-turn resistor clockwise until it stops, and then wait until the LED goes out in turned off and try to turn it on again to make sure the UPS is working, and then adjust the protection. If everything is soldered correctly and the correct part ratings are used, the UPS will start. Further, when you make sure that the UPS turns on and there are all voltages at the output, you need to set the protection threshold. When setting up protection, be sure to load the UPS between the two arms of the main output winding (which is for powering the ULF) with a 100-watt light bulb. When the HL1 LED lights up when the UPS is turned on under load (a 100-watt lamp), you need to turn the variable multi-turn resistor R9 2.2 kOhm counterclockwise until the protection is activated when turned on. When the LED lights up when turned on, you need to turn it off and wait until it goes out and gradually twist it clockwise in the off state and turn it on again until the protection stops working,
you just need to turn a little, for example, 1 turn and not immediately by 5-10 turns, i.e. turned it off, turned it on and turned it on, the protection worked - again the same procedure several times until you reach the desired result. When you set the desired threshold, then, in principle, the power supply is ready for use and you can remove the mains voltage light and try to load the power supply with an active load, for example, 500 watts. Of course, you can play around with the protection as you like, but I don’t recommend testing with A short circuit, since this can lead to a malfunction, although there is protection, some capacitance will not have time to discharge, the relay will not respond instantly or it will stick and there may be a nuisance. Although I accidentally and not accidentally made a number of closures, the protection works. But nothing is eternal.

Or create a winding, you can assemble a pulse-type power supply with your own hands, which requires a transformer with just a few turns.

At the same time, a small number of parts will be required, and the work can be completed in 1 hour. In this case, the IR2151 chip is used as the basis for the power supply.

To work, you will need the following materials and parts:

1. PTC thermistor any type.
2. A pair of capacitors, which are selected with the calculation of 1 microfarad. at 1 W. When creating a design, we select capacitors so that they draw 220 watts.
3. diode assembly vertical type.
4. Drivers type IR2152, IR2153, IR2153D.
5. FETs type IRF740, IRF840. You can choose others if they have a good resistance indicator.
6. Transformer can be taken from old computer system units.
7. Diodes installed at the output, it is recommended to take from the HER family.

In addition, you will need the following tools:

1. soldering iron and consumables.
2. Screwdriver and pliers.
3. Tweezers.

Also, do not forget about the need for good lighting in the workplace.

Step-by-step instruction

The assembly is carried out according to the drawn up circuit diagram. The microcircuit was selected according to the features of the circuit.

Assembly is carried out as follows:

1. At the entrance install PTC thermistor and diode bridges.
2. Then, a pair of capacitors is installed.
3. Drivers necessary to regulate the operation of the shutters field effect transistors. If the drivers have index D at the end of the marking, it is not necessary to install FR107.
4. FETs installed without shorting the flanges. When mounting to a radiator, special insulating gaskets and washers are used.
5. transformers installed with shorted leads.
6. diode output.

All elements are installed in the designated places on the board and soldered on the reverse side.

Examination

In order to correctly assemble the power supply, you need to carefully consider the installation of polar elements, and you should also be careful when working with mains voltage. After disconnecting the unit from the power source, no dangerous voltage should remain in the circuit. With proper assembly, subsequent adjustment is not carried out.

You can check the correct operation of the power supply as follows:

1. Include in the chain the output is a light bulb, for example, 12 volts. At the first short start, the light should be on. In addition, you should pay attention to the fact that all elements should not heat up. If something is heating up, then the circuit is assembled incorrectly.
2. At the second start measure the current value with a tester. We give the block enough time to work in order to make sure that there are no heating elements.

In addition, it would be useful to check all the elements with a tester for the presence of high current after turning off the power.

1. As previously noted, the operation of the switching power supply is based on feedback. The scheme under consideration does not require a special organization of feedback and various power filters.
2. Particular attention should be paid to the choice of field-effect transistors. In this case, IR FETs are recommended, which are renowned for their resistance to thermal resolution. According to the manufacturer, they can work stably up to 150 degrees Celsius. However, in this scheme they do not heat up much, which can be called a very important feature.
3. If the heating of transistors occurs constantly, active cooling should be installed. As a rule, it is represented by a fan.

Advantages and disadvantages

The pulse converter has the following advantages:

1. High rate stabilization coefficient allows you to provide power conditions that will not harm sensitive electronics.
2. Designs under consideration have a high efficiency. Modern versions have this indicator at the level of 98%. This is due to the fact that losses are reduced to a minimum, as evidenced by the low heating of the block.
3. Large input voltage range- one of the qualities due to which such a design has spread. At the same time, the efficiency does not depend on the input current indicators. It is the immunity to the voltage indicator that makes it possible to extend the life of the electronics, since jumps in the voltage indicator are a frequent occurrence in the domestic power supply network.
4. Incoming current frequency affects the operation of only the input elements of the structure.
5. Small dimensions and weight, also cause popularity due to the proliferation of portable and portable equipment. Indeed, when using a linear block, the weight and dimensions increase several times.
6. Organization of remote control.
7. Less cost.

There are also disadvantages:

1. Availability impulse interference.
2. Necessity inclusion in the circuit of power factor compensators.
3. Complexity self regulation.
4. Less reliable due to the complexity of the circuit.
5. Severe consequences when one or more circuit elements exit.

When creating such a design on your own, it should be borne in mind that the mistakes made can lead to failure of the electrical consumer. Therefore, it is necessary to provide for the presence of protection in the system.

Device and features of work

When considering the features of the operation of the pulse unit, the following can be noted:

1. At first the input voltage is rectified.
2. Rectified voltage depending on the purpose and features of the whole structure, it is redirected in the form of a high-frequency rectangular pulse and fed to an installed transformer or filter operating at low frequencies.
3. transformers are small in size and weight when using a pulse block due to the fact that increasing the frequency allows you to increase the efficiency of their work, as well as reduce the thickness of the core. In addition, a ferromagnetic material can be used in the manufacture of the core. At low frequency, only electrical steel can be used.
4. Voltage stabilization occurs through negative feedback. Through the use this method, the voltage supplied to the consumer remains unchanged, despite fluctuations in the incoming voltage and the load created.

Feedback can be organized as follows:

1. With galvanic isolation, optocoupler or transformer winding output is used.
2. If you do not need to create a decoupling, a resistor voltage divider is used.

In similar ways, the output voltage is maintained with the desired parameters.

Building Blocks switching power supply, which can be used, for example, to regulate the output voltage when powered , consists of the following elements:

1. Input part, high voltage. It is usually represented by a pulse generator. The pulse width is the main indicator that affects the output current: the wider the indicator, the greater the voltage, and vice versa. The pulse transformer stands on the section of the input and output parts, conducts the selection of the pulse.
2. There is a PTC thermistor on the output side.. It is made of a semiconductor and has a positive temperature coefficient. This feature means that when the temperature of the element rises above a certain value, the resistance indicator rises significantly. Used as a security key mechanism.
3. Low voltage part. A pulse is removed from the low-voltage winding, rectification occurs using a diode, and the capacitor acts as a filter element. The diode assembly can rectify the current up to 10A. It should be borne in mind that capacitors can be designed for different loads. The capacitor carries out the removal of the remaining pulse peaks.
4. Drivers carry out the damping of the resulting resistance in the power circuit. During operation, the drivers alternately open the gates of the installed transistors. Work occurs at a certain frequency
5. FETs are chosen taking into account the resistance indicators and the maximum voltage in the open state. At a minimum value, the resistance significantly increases efficiency and reduces heating during operation.
6. Standard transformer for downgrade.

Given the selected scheme, you can begin to create a power supply of the type in question.

The circuit is nowhere simpler - it operates at a frequency of 100 kHz and contains a minimum of inexpensive, common parts. The frequency is set by a resistor that hangs on the second leg of the microcircuit (in this case, 10 kOhm). The IR2151-2153 chip is a FET gate driver. Practice has shown that snubbers to suppress high-frequency dirt in this unit are not required. This circuit can draw up to 500 watts of power. Here, according to the description of the author, home-made transformers also work. This simple, proven circuit is great for powering amplifiers, charging batteries, 12-volt halogen spotlights, and more.

The scheme does not require any adjustment and starts working immediately. In my version, I used a transformer from a faulty computer power supply and took all the details except for the microcircuit, transistors and a powerful 47 kOhm resistor from there. On the rectifier diagram mains voltage there is a diode bridge - I also used diodes from the ATX block (the board is designed for a bridge). Input high-voltage capacitors are calculated from the consideration of 1 microfarad of capacitance per 1 watt of power. In this case, the capacitors are designed for a power of 220 watts. It is possible to control the frequency in series with a 10 kΩ resistor to put a 5 kΩ variable. After all, when the frequency changes, the output voltage changes. I also want to add that diodes like KD213 do not work here - they get very hot, you need to put something faster. Here is a photo of my version. I did not install a diode bridge at the output, since it stands separately along with the filter capacitors in the amplifier itself. Transistors used IRF840, as they are most suitable for this power supply.

In the photo, it pulls a 50-watt load, the diode is turned on to reduce the voltage, since the output is 22 volts. I did it with a marker, it took about 10 minutes. Transistors are mounted on a common radiator through mica gaskets.

The archive is given on the diagram. I’ll also add that the cost of the radio components cost everything in three dollars. Author of the article: Ksyunya.