A simple switching-mode power supply on IR2153
All hobby electronic components are very diverse but they all have one thing in common: almost every complete construction needs a power supply, often a very powerful one. Conventional transformers are heavy and expensive, the more so that not everyone has a choice for different voltages in the “nightstand”. The solution is obvious, switching power supply is compact, cheap (we are talking about the power conditionally up to 500W), and if you do not need an exceptional quality of output voltage – very simple, reliable and does not require adjustment. Of course, if made with straight hands on a properly laid circuit board from serviceable parts.
A reader familiar with the price lists of trading companies will say: Wow, a ready-made transformer costs almost the same! And he will be right, if you buy new parts at retail, it will not quite come out cheap. However, any practicing electronic engineer somewhere in range will probably find a power supply from an old desktop computer, which will cost nothing. AT, ATX, in any of these rarities you will find 90 percent of the necessary components. Well, to buy something cheap is not a problem.
The need for such light and compact PSU for the last couple of weeks I had twice: I needed a power supply for a soldering station on a T12 rod (25V x 4A) and power for a computer-grade internal oscillator (plus/minus 27V with current up to 4A). But I wanted something simple and not stabilized, reliable and not demanding winding the transformer from scratch, from the “underbrush” of the drawer with the details. I chose a very common half-bridge driver (I didn’t want to tinker with inverters, I had to wind them with a transformer, choose the clearance, etc.) IR2153D (chips without D are also good, just a small nuance in the circuit) or I could take the more modern IRS2153 analog.
Why this chip? Several reasons: cheap, widespread, simple connection with minimum of external components, initial “tuning” for gate control of “upper” and “lower” power MOSFETs without special transformers, frequency independent fixed deadtime of 1,2µs, wide range of frequencies, up to 100kHz according to the datasheet. Of course, immediately I wanted to add stabilization and protection, but for these purposes there are much more suitable chips, and for the simplest “electronic transformer” the selected chip is just right.
The datasheet from the manufacturer is quite laconic: no reference board layout, no different applications, just characteristics tables with brief explanations. To be fair, it should be noted that all the necessary information is available, but some experience in developing pulse sources is required to build something for your needs from scratch. I’ve filtered the last ones for the reason mentioned above. I kept about 10 simple ones for analysis (I don’t recommend anyone to copy designs blindly without getting into basic principles of work and without making sure that there are no gross mistakes in the circuit).
The most superficial review made me sad: all circuits selected on the criterion of simplicity had obvious mistakes or big drawbacks, not to mention the layout of printed circuit boards. Therefore I decided to recollect my experience at one of the power supply companies and compile a more or less correct schematic. The printed circuit board also decided to develop it by myself, firstly, to avoid someone else’s mistakes, and secondly – for the available components after disassembly of the nameless power supply (ATX 400W). As said before, there is everything you need except for the chip itself, but it really costs a penny (if you buy it, and you can look at various boards from “electronic chokes” of daylight lamps) and is available in almost any specialized store. No, I’m wrong, there were no power “poles” with isolated gate and N-channel, but probably everybody has them, you just have to choose the right pair (by the way, they don’t have to be identical, you can just use the ones with similar parameters). In the disassembled power supply the power switches were bipolar, they were not suitable for the circuit I had in mind.
A simple homemade switched-mode power supply with IR2153
Instructions for making a universal, simple switching-mode power supply on IR2153 with your own hands. A schematic, more than 40 step-by-step photos and detailed explanations are provided.
IR2153 switching power supply schematic, components needed
A detailed switching-mode power supply schematic
The first thing that catches your eye is the use of two high voltage capacitors instead of one for 400V. So you can kill two birds with one stone. You can get these capacitors from old computer power supplies without spending money on them.
If you don’t have a power supply, the price of a couple of these capacitors is lower than for a single high voltage capacitor. The capacitors have the same capacity and should be based on 1 μF per 1 watt of output power. This means that for 300 watts of output power you will need a pair of 330 µF capacitors each.
It is also important to consider the following correspondence:
- 150W = 2×120μF
- 300W = 2×330 uF
- 500W = 2×470μF
The next feature of the circuit is the power supply for the IR2153. Everybody who has ever built a block with this circuit has had to deal with the high temperature of the supply resistors.
Even if you supply them with AC power a lot of heat is released. To avoid this we use a capacitor instead of a resistor. This will prevent the element on the power supply from heating up.
Also the board is equipped with a protection, but in the original version of the circuit it was not.
After tests on the layout it turned out that there was too little space to install the transformer and so the circuit had to be enlarged by 1 cm, this gave extra space to install the protection. If it is not needed, you can simply put jumpers instead of the shunt and not install the components marked in red.
The protection current is adjusted with a trimmer resistor:
The ratings of the shunt resistors vary according to the maximum output power. The higher it is, the lower the resistance is needed. For example, up to 150 W you need 0.3 ohm resistors. If the power is 300 W, it is better to use 0.2 Ohm resistors. For 500 W or more, you should use 0.1 Ohm resistors. This unit should not be assembled with a power higher than 600 W.
Also it is necessary to say a few words about the operation of the protection. It is hiccuping here. The starting frequency is 50 Hz. This is because the power is taken from AC, hence the latch resets with the mains frequency.
If you need a latching variant, then the IR2153 chip needs to be powered DC, or more precisely, from high voltage capacitors. The output voltage of this circuit will be taken from a double half-period rectifier.
The main diode will be a Schottky diode in the case of TO-247, you choose the current for your transformer.
If you don’t want to take a big case, you can easily change it to TO-220 in Layout program. On the output is a 1000 uF capacitor, it is enough for any current, because at high frequencies the capacitance can be less than for 50 Hz rectifier.
Some auxiliary elements in the transformer harness should also be mentioned:
Snubbers
Smoothing capacitors.
In addition, we do not forget the Y-capacitor between the high and low side earths, which dampens noise on the output winding of the power supply.
Y-capacitor
The frequency hopping part of the circuit should not be left out.
This is a 1 nF capacitor, its nominal value is not recommended to change, but the resistor of the frequency hopping part was fine-tuned. The first of them is the precise selection of the right resistor, and the second is a small adjustment of the output voltage with the frequency. Now a little example, let’s say you’re making a transformer and you see that at 50 kHz the output voltage is 26V, and you want 24V. By changing the frequency you can find the value where you want 24V at the output. When setting this resistor you use a multimeter. Clamp the pins into the crocodiles and turn the knob of the resistor to get the resistance you want.
It is a 1 nF capacitor, we do not recommend to change its nominal value, but the resistor of the set part can be set as a trimmer, there are reasons for that. The first one is the precise selection of the right resistor, and the second one is a small adjustment of the output voltage with the frequency.
A small example: let’s say you are making a transformer and you see that at 50kHz the output voltage is 26V and you want 24V. By changing the frequency, you can find a value that will give you the 24V you want at the output. When setting this resistor you use a multimeter. Clamp the pins into the crocodiles and by turning the knob of the resistor, achieve the desired resistance.
You can download the printed circuit board for the IR2153 switched-mode power supply below:
The IR2153 Switch Mode Power Supply – Home-Built
Now you can see the two breadboards that were tested. They are very similar but the one with the protection is a bit bigger.
The breadboard was made so that you can get the board made in China.
Here is the board ready to go. It looks like this. Now a quick walkthrough of the main elements not mentioned before. First of all these are the fuses. We have 2 fuses here, one on the high and one on the low side.
Next we see the filter capacitors.
You can get them from an old computer power supply. The choke is wound on a t-9052 ring, 10 turns of 0.8 mm 2-wire. However, you can use the choke from the same computer power supply. The diode bridge can be any one with at least 10A current.
There are also 2 resistors on the board to discharge the capacitance, one on the high side and one on the low side.
The choke on the low side is left, it can be wound with 8-10 turns on the same core as the mains one. As we see, this board is designed for toroidal cores, because they have the same size as W-shaped cores, but have more power.
Testing of a home-built switched-mode power supply with IR2153
Now it is time to test the device. So far, the main tip is to do the first power up with a 40W light bulb.
If everything works as it should, you can drop the bulb. Let’s check the circuit for operation. As you can see, the output voltage is present. Let’s see how the protection reacts. Fingers crossed and eyes closed, short the secondary leads.
As you can see, the protection is working and everything is fine. Now we can put more stress on the unit. To do this we use our electronic load. We connect two multimeters to monitor the current and voltage. We start to increase the current slowly.
As we can see with 2A load the voltage has dropped only slightly. If you put a more powerful transformer, the sag will decrease, but it will still be, because this unit has no feedback, so it is preferable to use it for less capricious circuits.
- See also how to build a 6 volt PSU with a BQ24450.
This is a video on making a switched mode power supply with IR2153:
