Transformer power supply 5v 2a. Power supply for LED strip ARPV-LG05150
Gentlemen Technomaniacs, the holiday has come to our street, sharpen your fangs! You will have hard dismemberment, doping, and black jack with whores with wires!
My last review of this year, kick, trample, tear into small pieces - I’m yours!
But the power supply is generally not bad, it’s worth taking a closer look, let’s go...
First, a saying, (just don’t laugh who read my review about the mouse:) I bought myself a miracle tablet on Windows8.1 PIPO W2, (well, I asked you not to laugh :), and this PIPO is charged from a 5V power supply with a Nokia thin type plug , but maybe from microUSB. And BP on 5V with microSb in my zoo of different PSUs was not found, sadness is straight, disordered, I didn’t understand such a BP, I don’t know how to eat!
Where do heel and I go in such cases? Yes, an ash tree stump - TO CHINA! I poked around their Chinese shops in search of the power supply I needed and unexpectedly discovered a very interesting (according to the description) power supply on the store’s website Banggood, I rarely visited this store and only made a couple of orders there, well, I’m not buying tea from a cow, let’s take a chance and see what kind of comrade Sukhov BP this is. Along the way, I also ordered 3 and, as it turned out, good microUSB OTG cables, for those interested, check out the link.
They sent it quickly, I checked it, everything turned out to be working, the tablet is charging, it’s not heating up, it seems that Isho needs to live happily, but no, I can’t do this, my blood is boiling like a vampire, my hands and claws are itching, my fangs are thirsty for meat! Aaaaah!
The bastard turned out to be strong, I beat him with a wooden mallet and picked at him with a knife and drove awl needles under his body, but at least he didn’t care! The Chinese did not spare the dichloroethane glue, they decided to starve me to death - if you don’t wait, a hacksaw and a homemade cutter did their dirty work, dumping all the disease’s entrails out! Woohoo!
Unfortunately, the life-time photograph of the BP was not preserved, I was in such a hurry, so thirsty for blood that, alas, I didn’t even make photoceramics, only this sign on the body reminds us of his TTD: 
And this is it immediately after opening: 
Let's talk a little about what is being opened; information from the store is extremely scarce:
Description:
Universal EU 5V 3A Micro USB Cable Charger Power Adapter For Tablet
This is a EU mains 5V 3A charger which is suit for most kind of tablet PC.
Portable universal power adapter charger for tablet PC.
Safe and Easy to use and carry
Elegant and compact designed
Small and light, easy to take away when at home or traveling.
Specification:
Input:100-240V AC,50/60Hz
Output:DC 5V 3A
Weight:70g
After opening it, the first thing he surprised me with was the board - it was made of GLASS TEXT LITE, which you will agree is not often seen in our sublunary world! Before I start reading the obituary and testing what is being opened, look at a few photos of the board with different sides, or rather on both sides, I didn’t remove the sides, believe me, it’s fiberglass: 
And this is its cable and black jack, the marking 20AX2C VW-1SC is clearly readable on the cable, cable length is 90cm, the size of the metal pin of the black jack is microUSB 7mm (micro however:) 
Now the test results. I did all the measurements WITHOUT a CABLE, connecting directly to the board to eliminate the influence of wires and contacts. I usually replace the original cables with silicone ones that are more flexible, longer and thicker, which is why I unsoldered the cable.
Voltage:
no load - 5.26V
current 1.15A - 5.26V
current 2.4A - 5.25V
I didn’t raise the current above 2.4A, why force the power supply, I don’t need anything more from it anyway. I didn’t measure the pulsations either, I was too lazy :), but considering the circuit with two electrolytes at the output and a through-flow choke, I can assume an equally good result. I frankly liked the circuit, for an inexpensive device it is more than decent, of course, when compared with the branded power supplies I have, that is, there are some simplifications, well, it’s the same company and their prices are outrageous.
Now what I didn’t like and requires additional finishing:
1) The board does not fit into the slots of the case, it is shorter. The solution was to use a cambric spacer: 
2) There is no light or resistor installed on the board, there is no power-on indication, I plugged it into a socket, but whether there is a contact or not is not clear! I installed the light and a 1k resistor, drilled a hole in the lid for the light, and at the same time drilled holes on the sides for cooling.
3) The markings on the top of the board “-” and “+” are mixed up. I painted it with red and black markers, it will do, not for sale :) 
With parts soldered and power wires replaced, before final assembly: 
In an extension cord along with the native power supply from the PIPO W2 tablet: 
I won’t draw any conclusions, if the review is useful, I’ll be glad, I promise not to write more this year, haters rejoice! :))))))))))))))))))))))))))))))))))
P.S. Based on numerous requests, I provide oscillograms of ripples.
The measurements were carried out on a load connected via a power supply cable by connecting to a microUSB through a microUSB female socket, so the results of current and voltage measurements differ from the original ones, measured directly on the board (without cable and connectors). The power supply almost did not heat up during the measurements.
1) Current 1A, load voltage 5V: 
2) Current 2A, load voltage 4.6V: 
Power supplies with transformers at a frequency of 50 Hz today have practically lost their position to pulsed ones with a high operating frequency, which, with the same output power, have, as a rule, smaller dimensions and weight, and higher efficiency. The main limiting factors for self-manufacturing of switching power supplies by radio amateurs are difficulties in calculating, manufacturing or purchasing a ready-made pulse transformer or a ferrite magnetic core for it. But if you use a ready-made transformer from an ATX computer power supply to assemble a low-power switching power supply, the task becomes much easier.
I happened to have a faulty computer power supply IW-ISP300J2-0 (ATX12V300WP4). The fan was jammed in it, the low-power Schottky diode was broken, and more than half of all installed oxide capacitors were swollen and lost capacity. However, the standby voltage at the output was +5VSB. Therefore, it was decided, using a pulse transformer of the standby voltage source and some other parts, to manufacture another switching power supply with an output voltage of 5 V at a load current of up to 2.5 A.
In an ATX power supply, the standby voltage source nodes are easy to isolate. It provides a voltage of 5 V and is designed for a maximum load current of 2 A or more. True, in older power supplies of this type it can be designed for a current of only 0.5 A. If there is no explanatory inscription on the label of the unit, you can be guided by the fact that the standby voltage source transformer with a maximum load current of 0.5 A is significantly less than the source transformer by 2 A.
The circuit of a homemade switching power supply with an output voltage of 5...5.25 V at a maximum load current of 2.5 A is shown in Fig. 1. Its generator part is built on transistors VT1, VT2 and pulse transformer T1 in the image and likeness of the computer unit from which the transformer was removed.
Rice. 1. Scheme of a homemade switching power supply
It was decided not to repeat the secondary components of the original power supply (after the +5 V voltage rectifier), but to assemble them according to the traditional circuit with an integrated parallel voltage stabilizer as a unit for comparing the output voltage with the reference one. The input surge filter is assembled from existing parts, taking into account the free space for their installation.
The alternating voltage of the 230 V network through the fuse link FU1 and the closed contacts of the switch SA1 is supplied to the RLC filter R1C1L1L2C2, which not only protects the unit from interference from the supply network, but also prevents the interference generated by the pulse unit itself from entering the network. Resistor R1 and chokes L1, L2, in addition, reduce the surge of current consumption when the unit is turned on. After the filter, the mains voltage is supplied to the bridge diode rectifier VD1-VD4. Capacitor C9 smoothes out the ripples of the rectified voltage.
The generator unit of the voltage converter is assembled on the high-voltage field-effect transistor VT2. Resistors R2-R4 are designed to start the generator. The total power of these resistors is increased because printed circuit board The power supply from which they were removed was noticeably darkened underneath as a result of overheating. For the same reason, the damping resistor R8 is installed with a higher power, and a more powerful diode than in the prototype is used as VD6.
Zener diode VD5 protects field-effect transistor VT2 from exceeding the permissible voltage between the gate and source. The bipolar transistor VT1 houses an overload protection and output voltage stabilization unit. When the source current of transistor VT2 increases to 0.6 A, the voltage drop across resistor R5 will reach 0.6 V. Transistor VT1 will open. As a result, the voltage between the gate and source of field-effect transistor VT2 will decrease. This will prevent a further increase in current in the drain-source channel of the field-effect transistor. Compared to the prototype, the resistance of resistor R5 was reduced from 1.3 to 1.03 Ohms, resistor R6 was increased from 20 to 68 Ohms, and the capacitance of capacitor C13 was increased from 10 to 22 μF.
The voltage from winding II of transformer T1 is supplied to the Schottky rectifier diode VD8, the voltage swing at the terminals of which is about 26 V. Ripple of the rectified voltage is smoothed out by capacitor C15. If for one reason or another the output voltage of the power supply tends to increase, the voltage at the control input of the parallel voltage regulator DA1 increases. The current flowing through the emitting diode of optocoupler U1 increases, and its phototransistor opens. The resulting transistor VT1 opens reduces the voltage between the gate and source of the field-effect transistor VT2, which returns the output voltage of the rectifier to the nominal value. The circuit of resistor R16 and capacitor C16 prevents self-excitation of the stabilizer.
The manufactured power supply is equipped with a PA1 pointer load current meter, which significantly increases its ease of use, since it allows you to quickly estimate the current consumed by the load. The shunt for microammeter PA1 is the ohmic resistance of the inductor winding L4. LEDs HL1 and HL2 illuminate the microammeter scale.
The output connectors XP2 and XS1 receive voltage through the L5C19 filter. The VD9 zener diode with the VD10 diode prevents an excessive increase in the output voltage when its stabilization circuits malfunction.
The operating frequency of the converter is about 60 kHz. With a load current of 2.3 A, the ripple range of the rectified voltage on capacitor C15 is about 100 mV, on capacitor C18 is about 40 mV, and at the output of the power supply is about 24 mV. These are very good indicators.
The efficiency of the power supply at a load current of 2.5 A is 71%, 2 A is 80%, 1 A is 74%, 0.2 A is 38%. The output short circuit current is about 5 A, the power consumed from the network is about 7 W. Without load, the unit consumes about 1 W from the network. Measurements of power consumption and efficiency were carried out when the unit was powered with a constant voltage equal to the amplitude of the network voltage.
During long-term operation with maximum load current, the temperature inside its case reached 40 ° C at an ambient temperature of 24 ° C. This is significantly less than that of numerous small-sized switching power supplies included in the kits of various household electronic devices. With a load current equal to half the declared maximum value, they overheat by 35...55 o C.
Most of the parts of the described power supply are installed on a board measuring 75x75 mm. Installation - double-sided hinged. A plastic junction box with dimensions of 85x85x42 mm for external electrical wiring is used as a housing. The block in the open case is shown in Fig. 2, and its appearance is shown in Fig. 3.
Rice. 2. Block in an open case
Rice. 3. Appearance block
When manufacturing the block, special attention should be paid to the phasing of the windings of transformer T1; the beginning and end of any of them should not be mixed up. The used transformer 3PMT10053000 (from the computer power supply mentioned above) also has a -12 V winding intended for the voltage rectifier, which is not used in this case. Instead, you can use almost any similar transformer. For guidance when selecting a transformer, I give the inductance values of the windings used: I - 2.4 mH, II - 17 μH, III - 55 μH.
The M68501 microammeter (level indicator from a domestic tape recorder) was used as PA1. Please note that microammeters of this type from different years of production have a very large variation in the resistance of the measuring mechanism. If it is not possible to set the desired measurement limit by selecting resistor R13, you need to connect a wirewound resistor of small resistance (approximately 0.1 Ohm) in series with inductor L4.
When calibrating the microammeter, it unexpectedly turned out that it was very sensitive to static electricity. A brought plastic ruler could deflect the instrument needle to the middle of the scale, where it could remain even after the ruler was removed. This phenomenon was eliminated by removing the existing film scale. Instead, sticky aluminum foil was glued, which also covered the free areas of the body. The foil screen should be connected with a wire to any terminal of the microammeter. You can try treating the microammeter body with an antistatic agent.
The paper scale printed on the printer is glued in place of the removed one. A sample scale is shown in Fig. 4. As you can see, with this microammeter it is noticeably nonlinear.
Rice. 4. Sample scale
Resistor R1 is imported non-flammable. Instead of such a resistor, you can install a wirewound with a power of 1...2 W. Domestic metal film and carbon resistors are not suitable as R1. Other resistors general use(C1-14, C2-14, C2-33, C1-4, MLT, RPM). Surface mount resistor R19 is soldered directly to the pins of socket XS1.
Oxide capacitors are imported analogs of K50-68. The use of capacitors C15, C18, C19 with a rated voltage of 10 V instead of oxide capacitors with a voltage of 6.3 V, often used in switching power supplies, significantly increases the reliability of the device. Film capacitor C2 with a capacity of 0.033...0.1 μF is designed to operate at an alternating voltage of 275 V. The remaining capacitors are imported ceramic. Capacitors C14, C17 are soldered between the terminals of the corresponding oxide capacitors. Capacitor C20 is installed inside plug XP2.
The powerful S30D40C Schottky diode assembly was taken from a faulty computer power supply. In the device under consideration, it can operate without a heat sink. You can replace it with MBR3045PT, MBR4045PT, MBR3045WT. MBR4045WT At maximum load current, the housing of this assembly heats up to 60 o C - this is the hottest element in the device. Instead of a diode assembly, you can use two conventional diodes in a DO-201AD package, for example, MBR350, SR360, 1N5822, connecting them in parallel. An additional copper heat sink, shown in Fig., must be attached to them on the side of the cathode terminals. 5.
Rice. 5. Additional copper heat sink
Instead of 1N4005 diodes, 1 N4006, 1 N4007, UF4007, 1N4937, FR107, KD247G, KD209B are suitable. The FR157 diode can be replaced with FR207, FM207, FR307, PR3007. One of the listed diodes is suitable instead of KD226B. Any of the UF4003, UF4004, 1N4935GP RG2D, EGP20C, KD247B can replace the FR103 diode. Instead of the BZV55C18 zener diode, 1N4746A, TZMC-18 are suitable.
LEDs HL1, HL2 - white glow from the LCD backlight unit of a cellular telephone. They are glued to the microammeter with cyanoacrylate glue. The KSP2222 transistor can be replaced by any of the PN2222, 2N2222, KN2222, SS9013, SS9014, 2SC815, BC547 or KT645 series, taking into account differences in pin assignments.
The SSS2N60B field-effect transistor was removed from the faulty power supply and installed on a ribbed aluminum heat sink with a cooling surface area of 20 cm2, and all terminals of the transistor must be electrically isolated from the heat sink; when the power supply operates with maximum load current, this transistor heats up to only 40 o C. Instead of the SSS2N60B transistor, you can use SSS7N60B, SSS6N60A, SSP10N60B, P5NK60ZF, IRFBIC40, FQPF10N60C.
The EL817 optocoupler can be replaced with another four-pin optocoupler (SFH617A-2, LTV817, PC817, PS817S, PS2501-1, PC814, PC120, PC123). Instead of the LM431ACZ microcircuit, any functionally similar one in the TO-92 package (TL431, AZ431, AN1431T) will do.
All chokes are of industrial manufacture, and the magnetic cores of the chokes L1, L2, L4 are H-shaped ferrite. The resistance of the inductor winding L4 is 0.042 Ohm. The larger this inductor is, the less its winding will heat up, the more accurately the PA1 microammeter will measure the load current. Inductor L5 is wound on a ring magnetic circuit; the lower the resistance of its winding and the greater its inductance, the better. Choke L3 is a 5 mm long ferrite tube placed on the terminal of the common cathode of the VD8 diode assembly.
The XP2 plug is connected to the C19 capacitor with a 2x2.5 mm 2 double stranded wire, 120 cm long. The XS1 USB-AF socket is fixed in the hole in the device body with glue.
The first connection of the manufactured device to the network alternating current carried out without load through an incandescent lamp with a power of 40...60 W at 235 V, installed instead of the fuse-link FU1. Preliminary load tests are performed by replacing FU1 with an incandescent lamp with a power of 250...300 W. The filaments of incandescent lamps should not glow during normal operation of the power supply. Manufactured from faultless parts, the device starts working immediately.
If necessary, by selecting resistor R13 you can set the ammeter readings. By selecting resistor R14, the output voltage of the power supply is set to 5...5.25 V. The increased voltage compensates for its drop on the wires connecting the unit to the load.
The manufactured power supply can be used in conjunction with a modified USB hub, to which you can connect up to four external 2.5-inch hard drives operating simultaneously. The power will be sufficient to power, for example, devices such as.
Literature
1. Butov A. Refinement of the USB hub. - Radio, 2013, No. 11, p. 12.
2. Butova. Voltage converter 5/9 V for powering radio receivers. - Radio, 2013, No. 12, p. 24, 25.
A 5V power supply is a device used to create the voltage necessary for the operation of industrial automation devices. High demands are placed on products of this class. High-quality units must provide reliable and safe power supply, have a wide range of operating temperatures, and be resistant to vibration.
Traditionally, a 5V power supply is installed in cabinets on DIN rails, so the housings of all devices have an appropriate design, also designed for wall mounting in a casing. The operation of industrial automation completely depends on the quality of production of power supplies: if the devices do not meet the stated requirements, the equipment becomes vulnerable.
Our catalog contains 5V power supplies from leading manufacturers:
- ARIES,
- Chinfa,
- MeanWell.
Power supply lines include 5, 10, 15, 18, 20, 30, 40, 45 and 60 W models. The units fully meet the requirements for safety, reliability, and electromagnetic compatibility.
For detailed information about 5V power supplies, please contact our managers. Consultations are provided by telephone.
