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Resonant voltage converter for LDs. Voltage converter for fluorescent lamp Transformerless converter for LDS 8 watt

Converter 12V - 220V for powering LDS from a computer power supply.

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The converter is used to power fluorescent lamps (FLLs) with electronic ballast. Electronic ballasts are separate devices that replace low-frequency chokes. As a rule, such ballasts are found in the fittings of finished LDS luminaires. The converter is guaranteed and reliable to work with ballasts of both powerful and “weak” lamps.
The converter is also used to power “economical” base-type LDS; for autonomous, bright and economical lighting of the house, garage, car interior.

This is a push-pull pulse converter assembled on a TL494 PWM controller (domestic analogue of 1114EU4), which makes the circuit quite simple. At the output there are highly efficient rectifier diodes that double the voltage. The output, of course, is constant voltage, but for electronic ballasts constant voltage and switching polarity are not relevant, because in the ballast circuit there is a diode bridge at the input.



As a step-up transformer, the converter uses a ready-made high-frequency transformer from the power supply unit (PSU) of the computer, which, like almost all the parts used in this circuit, can be taken from a faulty or unnecessary Unit, both AT and ATX; in our converter it will do the job as a booster.

You can wind the transformer yourself: To do this, find a suitable ferrite ring (outer diameter approximately 20-30 mm). The turns ratio is approximately 1:1:20, where 1:1 is two halves of the primary winding (10+10 turns), and 20 is, respectively, a secondary winding of 200 turns. First, the secondary is wound - evenly 200 turns with a wire with a diameter of 0.3-0.4 mm. Then, evenly, two halves of the primary winding (we wind 10 turns, make a middle tap, then wind the remaining 10 turns in the same direction). For the half-windings, a stranded, silver mounting wire with a diameter of 0.8 mm was used (you don’t have to force it and use another wire, but stranded and soft is better).
Another option for manufacturing (remaking) a transformer is to purchase the so-called. "electronic transformer" for 12 volt halogen lamps for lighting ceilings and furniture (in lighting equipment stores). It contains a suitable transformer on the ring. You just need to remove the secondary winding, which consists of a dozen turns. And the half-windings can be wound differently - we fold a piece of wire (calculate the length) in half and wind it with the double folded wire; We cut the middle of the wire (the bend point) - we get the so-called two ends (or two beginnings) of windings. To the end of one wire we solder the beginning of another - we get a common point of the half-windings.

Transistors are high-power MOS (metal-oxide-semiconductor) field-effect transistors, which are characterized by shorter response times and simpler control circuits. IRFZ44N, IRFZ46N, IRFZ48N work equally well (the higher the number, the more powerful and more expensive).
The converter uses HER307 diodes (304, 305, 306 are suitable). Domestic KD213 work great (more expensive and larger).
The output capacitors can be of smaller capacity, but with an operating voltage of 200V. Capacitors from the same computer power supply with a diameter of no more than 18 mm were used (or edit the printed circuit board design).
Install the chip on the panel; it will be easier to live this way.

ESTABLISHMENT comes down to correct ( carefully) installing the microcircuit into the panel. If it does not work, check the presence of 12V supply voltage. Check ornot mixed upR1 and R2. Everything should work.
A radiator is not necessary, because prolonged operation does not cause noticeable heating of the transistors, but if you want to put it on a radiator, then, be careful, do not short-circuit the flanges of the transistor housings through the radiator. Use insulating gaskets and bushing washers from the same computer power supply. Although, for the first start-up, a radiator may not hurt; at least the transistors will not immediately burn out in the event of installation errors or a short circuit at the output, or in the event of an “accidental” connection of a 220V incandescent lamp.
The power supply of the circuit must be convincing, because the current consumption of one copy of the “economical” LDS from a sealed acid battery was 1.4 A at voltage 11.5V; total 16 W (although the lamp packaging says 26 W).Protection of the circuit from overload and reversals can be implemented through a fuse and a diode at the input.
Be careful!The output of the circuit is high voltage and can cause a very serious shock. Capacitors hold a charge for more than a day. There are no discharge circuits at the output. Short-circuiting not allowed, discharge either with a 220V incandescent lamp or through a 1 mOhm resistance.

Photo of the converter:



For the converter, depending on the dimensions of the transformer, the author made two drawings of the printed circuit board (board size 50x55 mm).

Board 1. () Board 2. (download in Sprint Layout format)


CONVERTER 12V - 220V USING A STANDARD TRANSFORMER.




The proposed converter circuit is easy to manufacture and is made with a minimum number of parts. The device does not have any special features and does not require adjustment. The converter can be used as a backup power source. The transformer is used ready-made - from a conventional power supply, but in reverse connection. It has two 9V windings with a maximum load current of 1.2... 1.5A and a 220V mains winding.

The voltage converter provides mains voltage 220V 50 Hz for a load of up to 5 W. It consists of a master oscillator with a frequency of 100 Hz and a trigger-divider on IC O, powerful MOS switches VT1 VT2 and a 6-watt mains transformer with secondary windings 2x9V, included as a step-up. When the load increases to the maximum, the output voltage decreases from 250V to 200V, which is acceptable for most devices. In this case, the current consumed by the device increases from 80 to 630 mA.


More diagrams:

The transformer is wound on a ferrite rod (any) with a diameter of 6-8 mm, 60 mm long, wrapped with electrical tape.

I - 45 vit. with a wire with a diameter of 0.5 mm (or so)

II - 25 vit. 0.25mm (or so)

III - 600 vit. 0.25mm (or so)

Single-cycle pulse voltage converter 12-220V.

This voltage converter allows you to connect a load with a power of up to 100W. At idle, the current consumed by the converter does not exceed 0.5A. Input voltage range 9-15V. The operating frequency of the converter is about 20 kHz.

The transformer is made of two magnetic cores folded together from ferrite grade M2000NM1, standard size K32x20xb. The winding data is shown in the table.

Number .in itkov

PEL0.8...1.0

PEL0.25

PEL0.25

When making a transformer, the secondary winding is first wound. Winding is performed turn to turn, in one layer, followed by insulation with fluoroplastic or other insulating material. The primary winding is wound with two wires simultaneously (evenly distributing the turns on the magnetic core).


CONVERTER 12V/220V.

The converter (otherwise known as a DC/DC converter) can be used to connect standard network chargers from mobile phones. Preliminary calculations showed that, taking into account the losses from two conversions, the overall efficiency of the system will be about 65% (if we consider the efficiency of each device to be 80%, which is typical for low-power pulse converters).

The entire device is assembled on a printed circuit board measuring 40x60 mm (Fig. 2), the appearance is shown in the photograph at the beginning of the article. Output transformer: core 2 rings K20x12x6 ferrite 2000-NM1, step-up winding 180 turns with PELSHO 0.12 wire (wound first), primary winding 13 turns with PEL 0.6 wire folded in half. With this core, at the selected frequency, you can get a power of about 25...30 W (for this circuit, one ferrite ring is enough). The core cross-section is increased in order to reduce the number of turns in the windings.



The scheme does not require any settings.

You can check the quality of the wound transformer. When supplying an input supply voltage of 12V, the current consumption at “idle” with the connected resistor R6 should be 40...45mA, the output voltage should be 200V.

If so, then everything worked out. If the no-load current is higher, check the frequency using an oscilloscope at pin 9 or 10 (oscillation period 40 µs). If everything comes together, then the reason is in the transformer: short circuit of the turns, wrong core material.

In operating mode with the charger and phone connected, the current consumed from the 12V network is 300...400mA (if the battery in the phone is discharged, the current is higher), the voltage at the converter output in this mode is -160...170V.



Sources:
S. Yu. Stebenev; T. Nosov
http://radio-hobby.org/ ;

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Voltage converter for fluorescent lamp

I. NECHAYEV, Kursk

This converter can be used to power fluorescent lamps with a power of up to 20 W from a battery or other autonomous source with a voltage of 6... 12 V, for example, in camping conditions. Its circuit, similar to those widely used in many imported portable battery-powered fluorescent lamps, is shown in Fig. 1.


The basis of the converter - a blocking oscillator on transistor VT1 and transformer T1 - generates short pulses with a frequency of 30...40 kHz and an amplitude of 400 V, which are supplied to the fluorescent lamp EL1. Due to the high pulse frequency and inertia of the phosphor, the blinking of the lamp is completely invisible.

When adjusting the frequency using variable resistor R2, the pulse duration remains constant. Their duty cycle changes, and with it the brightness of the lamp. The higher the resistance introduced, the lower the frequency and the higher the duty cycle, the lower the brightness of the lamp and the lower the current consumed from the power source (for example, a car battery). When testing the converter with the F13W lamp, the current was 70 mA at minimum and 800 mA at maximum brightness.

The regulator is assembled on a single-sided printed circuit board measuring 35x85 mm, a fragment of which is shown in Fig. 2.


On the rest of it there are (glued or fastened with screws) the transformer T1 and the transistor VT1 with a heat sink. After soldering the leads, the housing of the variable resistor R2 is also fixed with glue. The appearance of the mounted board is shown in Fig. 3.


It is placed in a housing of a suitable size made of insulating material, leading the axis of the variable resistor into the hole on the front wall. The EL1 lamp can be installed in a standard fixture or one made independently from scrap materials.

Instead of the KT841A transistor, you can use the KT805A or KT847A. The heat sink area must be at least 15 cm2.

The magnetic core of transformer T1 is armored B30 made of M1500NM3 ferrite. It is assembled with a non-magnetic gap of 0.2...0.5 mm. Winding I - 24 turns of PEV-2 0.38...0.41 mm (in two wires), II - 7 turns of the same but single wire, III - 190 turns of PEV-2 wire 0.18...0 .2 mm. The latter is reliably isolated from other windings and the magnetic circuit with lacquered cloth or insulating tape.

Any fluorescent lamps with a power of 4...20 W can be connected to the converter, including those with burnt-out filaments. If the lamp power is less than 10 W, the number of turns of winding III should be reduced.

The converter will be able to operate at a lower (down to 6 V) supply voltage if the number of turns of winding II is reduced in proportion to the voltage. However, its efficiency is noticeably reduced, so using lamps with a power of more than 10 W in this case is not recommended.

When setting up the converter, resistor R1 is selected in such a way that in the right (according to the diagram) position of the variable resistor R2 slider, the brightness of the lamp is subjectively perceived as nominal, corresponding to its connection to the network according to a standard circuit with a “ballast” choke. If moving the slider to the opposite position reduces the brightness insufficiently or excessively, the value of the variable resistor should be increased or decreased accordingly.

Converter for LDS in 5 minutes

Well, very quickly you can assemble a 12-volt converter to power a fluorescent lamp from an old (unnecessary, burned out - underline as necessary) computer power supply. Literally in five minutes.

We will need a small list of parts from it:

  • An entire transformer of the EEL-19 brand from a standby power supply unit or an analogue;
  • Power key MJE13009 or equivalent (obviously, whole);
  • Radiator from there (or another area of ​​at least 40 cm²);
  • A pair of resistors and capacitors;
  • LDS at 18 W.

I saw the diagram somewhere on the Internet, here it is:

We don't need to rewind the transformer; it will work in its original form. We will change the circuit a little; it is not quite suitable for our transformer. There are two types of duty room transformers - small and large. We need a big one, like this:

First you need to decide on the purpose of the winding terminals. We look at the primary side of the transformer:

Paws from left to right: to +12V, to feedback, to the collector of the transistor. Transformer secondary side:

The left paws are for LDS, we don’t need the right two.

For other types of transformers, the terminals are located differently, I will tell you how to distinguish them. The +12 volt power supply is connected to the terminal of the transformer from which the 5V standby voltage is removed. The transistor collector is connected to the terminal from which the TL494 supply voltage was removed. The feedback is connected to the output that was the ground of the control unit of the power supply unit. The LDS is connected to the winding, which was the high-voltage winding in the duty power supply. All this can be tracked on the power supply circuit board or you can guess it yourself using the tester :)

The scheme was assembled completely out of the blue. The trifle is mounted on the terminals of the transistor.



Resistor R1 must be reduced to 39 Ohms, R2 - to 560 Ohms. Capacitor C2 can be 0.01–0.022 µF. The phasing of the secondary winding did not play any role. There were also no differences in connecting the first and second terminals of the secondary winding to the collector, and the LDS burned absolutely identically when its terminals were connected to each other.

In this circuit and with this transformer, the LDS ignites at 10V. You can disassemble the transformer and add another hundred turns to the secondary winding, which was done - see photo. In this case, the LDS will ignite from 6V and burn well from 12V. The circuit is operational with a power supply of up to 15V, but the transistor radiator needs to be increased. In any operating mode, the transformer does not heat up at all.

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This converter is used to power fluorescent lamps (FLLs) with electronic ballast. Electronic ballasts are separate devices that replace low-frequency chokes. As a rule, such ballasts are found in the fittings of ready-made LDS lamps. The converter is guaranteed and reliable to work with ballasts of both powerful and “weak” lamps.
The converter is also used to power “economical” base-type LDS; it was actually assembled for the purpose of autonomous, bright and economical lighting of the house, garage, and car interior. I decided not to assemble the electronic ballast but to use a ready-made one, because... the hemorrhoids-result ratio was in favor of ready-made solutions (it’s like making an incandescent lamp on your knees in our age).

Brief comments on the diagram. This is a push-pull pulse converter assembled on a TL494 PWM controller (a complete domestic analogue of 1114EU4), which makes the circuit quite simple. At the output there are highly efficient rectifier diodes that double the voltage according to the Delon or Greinmacher circuit (I didn’t want to swear). The output, of course, is constant voltage. For electronic ballasts, constant voltage and switching polarity are not relevant, because in the ballast circuit there is a diode bridge at the input (although the diodes there are not as “fast” as in our converter).
The converter uses a ready-made high-frequency step-down transformer from the computer power supply (in general, almost all the parts used in this circuit can be torn out from an unnecessary or faulty computer power supply), but in our converter it will become a step-up transformer. The step-down transformer can be taken from both AT and ATX power supplies. From my experience, the transformers differed only in size, but the location of the terminals was the same. A dead power supply unit (or a transformer from it) can be found in any computer repair shop.
You can wind the transformer yourself. Personally, my patience now is enough to manually wind no more than 20 turns, although in childhood I could wind a contour coil of 100 turns for a transistor receiver; the years take their toll.
So, we find a suitable ferrite ring (outer diameter approximately 20-30 mm). The turns ratio is approximately 1:1:20, where 1:1 is two halves of the primary winding (10+10 turns), and:20 is, respectively, a secondary winding of 200 turns. First, the secondary is wound - evenly 200 turns with a wire with a diameter of 0.3-0.4 mm. Then, evenly, two halves of the primary winding (we wind 10 turns, make a middle tap, then wind the remaining 10 turns in the same direction). For half-windings I use stranded, silver mounting wire with a diameter of 0.8 mm (you don’t have to force it and use another wire, but stranded and soft is better).
I offer another option for manufacturing (remaking) a transformer. You can purchase the so-called. “electronic transformer” for 12 volt halogen lamps for lighting ceilings and furniture (in lighting equipment stores it costs from 80 rubles). It contains a suitable transformer on the ring. You just need to remove the secondary winding, which consists of a dozen turns. And the half-windings can be wound differently - we fold a piece of wire (calculate the length) in half and wind it with the double folded wire; We cut the middle of the wire (the bend point) - we get the so-called two ends (or two beginnings) of windings. To the end of one wire we solder the beginning of another - we get a common point of the half-windings. I assure you that such a transformer works for me. It should be noted that a computer transformer works great in an “electronic transformer” circuit.

Conversion frequency is about 100 kHz (for calculation of the operating frequency, see the documentation for TL494).
C1 is 1 nanofarad, or 1000 picofarad, or 0.001 microfarad (all options for capacitance values ​​are equal); on the case the coding is 102; I set it to 152 - it works, but I assume that at a lower frequency.
R1 and R2 - set the width of the output pulses. The circuit can be simplified and these elements not installed, while the 4th contact of TL494 is set to negative; I don’t see the need to rape transistors with wide pulses.
R3 (together with C1) sets the operating frequency. We reduce the resistance R1 - we increase the frequency. We increase the capacitance C1 - we reduce the frequency. And vice versa.
Transistors are high-power MOS (metal-oxide-semiconductor) field-effect transistors, which are characterized by shorter response times and simpler control circuits. IRFZ44N, IRFZ46N, IRFZ48N work equally well (the higher the number, the more powerful and more expensive).
The converter uses HER307 diodes (304, 305, 306 are suitable). Domestic KD213 work great (more expensive, larger and more reliable).
The output capacitors can be of smaller capacity, but with an operating voltage of 200 V. Capacitors from the same computer power supply with a diameter of no more than 18 mm were used (or edit the printed circuit board design).
Install the chip on the panel; it will be easier to live this way.

Setup comes down to carefully installing the microcircuit into the panel. If it doesn’t work, check for the presence of 12 V supply voltage. Check R1 and R2, are they confused? Everything should work.
A radiator is not needed, because prolonged operation does not cause noticeable heating of the transistors. And if you want to install it on a radiator, then, be careful, do not short-circuit the flanges of the transistor housings through the radiator. Use insulating gaskets and bushing washers from a computer power supply. For the first start, a radiator will not hurt; at least the transistors will not immediately burn out in the event of installation errors or a short circuit at the output, or in the event of an “accidental” connection of a 220 V incandescent lamp.
The power supply of the circuit must be convincing, because The current consumption of one copy of the “economical” LDS from a sealed acid battery was 1.4 A at a voltage of 11.5 V; total 16 W (although the lamp packaging says 26 W).
Protection of the circuit from overload and reverse polarity can be implemented through a fuse and a diode at the input.
Be careful! The output of the circuit is high voltage and can cause a very serious shock. Then don't say you didn't warn me. Capacitors hold a charge for more than a day - tested on people. There are no discharge circuits at the output. Short-circuiting is not allowed; discharge either with a 220 V incandescent lamp or through a 1 mOhm resistor.
Photo of the converter.