Schematic diagram of the power supply ls 250 12. Design and principle of operation of the ATX power supply

This was collected using simple electrical diagram from everything that came to hand. Two TP20-14 transformers from small black-and-white TVs Elektronika-409, a dial voltmeter/ammeter from the recording level indicator of a cassette tape recorder. The most common parts are the ones that every radio amateur has lying around in his bins. And an noise-suppressing metal body made from scraps of aluminum plates.

Only connectors for connecting wires are purchased - springy pedals. I don’t know what you thought when looking at the front panel of the power supply, but two digital ALS are not a voltmeter, but simply indicate the mode of the pointer device (volts B or amperes A), and the second ALS shows the charging process by flashing. The measurement mode is switched by a button located under the ALS.

There is nothing unusual in the electrical circuit of the charging unit - voltage is supplied to the socket (and then to the battery) through a 50 Ohm resistor, which limits the current to 0.2A - this is enough for most lithium-ion and nickel cadmium batteries. And the charging process is controlled by the voltage drop across the resistor, which opens the transistor that controls the multivibrator. Moreover, the more charging current- the faster the letter Z (three) flashes on the ALS.

The second multivibrator is triggered by the current limiter and causes the blue LED to blink - on the top left of the case. The windings of two 16-volt transformers are connected in parallel, which provided a maximum current of 1A, and the voltage regulation was from 0 to 15V. I pasted such a scale onto the switchman, having previously printed it on a printer.

Many people assemble various radio-electronic structures, and their use sometimes requires a powerful power source. Today I’ll tell you how with an output power of 250 watts, and the ability to adjust the voltage from 8 to 16 volts at the output, from an ATX unit model FA-5-2.

The advantage of this power supply is output power protection (that is, against short circuit) and voltage protection.

Reworking the ATX block will consist of several stages

2. We unsolder from the circuit the parts that are in the +3.3v, -5v, -12v circuits (we don’t touch +5 volts yet). What to remove is shown in red, and what to redo is shown in blue in the diagram:

4. We provide power and voltage protection. Add two trim resistors:

Setting voltage protection in the power supply

Setting up the voltage protection is done as follows: we twist the resistor R4 to the side where the ground is connected, set R3 to maximum (higher resistance), then by rotating R2 we achieve the voltage we need - 16 volts, but set it 0.2 volts more - 16.2 volts, slowly turn R4 before the protection is triggered, turn off the block, slightly reduce the resistance R2, turn on the block and increase the resistance R2 until the output reaches 16 volts. If during the last operation the protection was triggered, then you went overboard with the R4 turn and will have to repeat everything again. After setting up the protection, the laboratory unit is completely ready for use.

ATX POWER SUPPLY, CIRCUIT

Computer power supplies are becoming more and more popular among radio amateurs every day.ATX. At relatively small price, they are a powerful, compact voltage source of 5 and 12 V 250 - 500 watts. BPATXcan also be used in chargers for car batteries, and in laboratory power supplies, and in welding inverters, and many more applications can be found for them with a certain amount of imagination. Moreover, if the power supply circuitATXand is subject to alteration, then minimal.

The circuit design of these power supplies is approximately the same for almost all manufacturers. A small difference concerns only AT and ATX power supplies. The main difference between them is that the AT power supply does not support the advanced power management standard in software. You can turn off this power supply only by stopping the supply of voltage to its input, and in ATX power supplies it is possible to programmatically turn it off using a control signal from the motherboard. As a rule, an ATX board is larger than an AT board and is elongated vertically.

In any computer power supply, the +12 V voltage is intended to power the disk drive motors. The power supply for this circuit must provide a large output current, especially in computers with many drive bays. This voltage is also supplied to the fans. They consume current up to 0.3 A, but in new computers this value is below 0.1 A. +5 volt power is supplied to all components of the computer, therefore it has very high power and current, up to 20 A, and the +3.3 volt voltage is intended exclusively for powering the processor. Knowing that modern multi-core processors have a power of up to 150 watts, it is not difficult to calculate the current of this circuit: 100 watts/3.3 volts = 30 A! Negative voltages -5 and -12 V are ten times weaker than the main positive ones, so there are simple 2-amp diodes without radiators.

The tasks of the power supply also include suspending the functioning of the system until the input voltage reaches a value sufficient for normal operation. Each power supply undergoes internal checks and output voltage testing before being allowed to start the system. After this, a special Power Good signal is sent to the motherboard. If this signal is not received, the computer will not work.

The Power Good signal can be used for manual reset if applied to the clock generator chip. When the Power Good signal circuit is grounded, clock generation stops and the processor stops. After opening the switch, a short-term processor initialization signal is generated and normal signal flow is allowed - a hardware reboot of the computer is performed. In computer power supplies of the ATX type, there is a signal called PS ON; it can be used by the program to turn off the power source.

Here you can download computer power supplies, and here is a very useful description, types and principle of operation of AT and ATX power supplies.To check the functionality of the power supply, you should load the power supply with lamps for car headlights and measure all output voltages with a tester. If the voltage is within normal limits. It is also worth checking the change in the voltage supplied by the power supply with a change in load.

The operation of these power supplies is very stable and reliable, but in the event of combustion, they most often fail powerful transistors, low-resistance resistors, rectifier diodes on the radiator, varistors, transformer and fuse.

Quite often when repairing or converting an ATX computer power supply to Charger or a laboratory source requires a diagram of this block. Considering that there are a great many models from such sources, we decided to collect a collection of this topic in one place.

In it you will find typical power supply circuits for computers, both modern ATX type and already noticeably outdated ATX. It is clear that newer and more relevant options appear every day, so we will try to quickly replenish the collection of schemes with newer options. By the way, you can help us with this.

Collection circuit diagrams on PSU ATX and AT

power unit personal computer- used to supply power to all components and components of the system unit. A standard ATX power supply must provide the following voltages: +5, -5 V; +12, -12 V; +3.3 V; Almost any standard power supply has powerful fan located from the bottom. On the rear panel there is a socket for connecting a network cable and a button to turn off the power supply, but on cheap Chinese versions it may not be available. WITH opposite side a huge pile of wires comes out with connectors for connecting the motherboard and all other components of the system unit. Installing the power supply into the case is usually quite simple. Installing a computer power supply into the system unit case To do this, insert it into the upper part of the system unit, and then secure it with three or four screws to the rear panel of the system unit. There are designs of the system unit case in which the power supply is placed in the lower part. In general, if anything, I hope you can get your bearings

Cases of breakdowns of computer power supplies are not uncommon. The causes of malfunctions can be: Voltage surges in the network alternating current; Poor workmanship, especially for cheap Chinese power supplies; Unsuccessful circuit design solutions; Use of low-quality components in manufacturing; Overheating of radio components due to contamination of the power supply or fan stoppage.

Most often, when a computer power supply breaks down, there are no signs of life in the system unit, the LED indication does not light up, there are no sound signals, and the fans do not spin. In other cases the fault does not start motherboard. At the same time, the fans spin, the indication lights up, the drives show signs of life and HDD, but there is nothing on the monitor display, just a dark screen.

Problems and defects can be completely different - from complete inoperability to permanent or temporary failures. As soon as you begin the repair, make sure that all contacts and radio components are visually in order, the power cords are not damaged, the fuse and switch are working, and there are no short circuits to ground. Of course, the power supplies of modern equipment, although they have general principles work, but the circuitry is quite different. Try to find a diagram on a computer source, this will speed up the repair.

The heart of any computer power supply circuit, ATX format, is a half-bridge converter. Its operation and operating principle are based on the use of push-pull mode. Stabilization of the device's output parameters is carried out using control signals.

IN pulsed sources The well-known TL494 PWM controller chip is often used, which has a number of positive characteristics:

ease of use in electronic designs
good operating technical parameters, such as low starting current and, most importantly, speed
availability of universal internal protective components

The operating principle of a typical computer power supply can be seen in the block diagram below:

The voltage converter converts this value from variable to constant. It is made in the form of a diode bridge that converts voltage and a capacitance that smoothes out oscillations. In addition to these components, additional elements may be present: thermistors and a filter. The pulse generator generates pulses at a given frequency, which power the transformer winding. HE performs the main work in a computer power supply, this is the conversion of current to the required values ​​and galvanic isolation of the circuit. Next, the alternating voltage from the windings of the transformer goes to another converter, consisting of semiconductor diodes that equalize the voltage and a filter. The latter cuts off ripple and consists of a group of inductors and capacitors.

Since many parameters of such a power supply “float” at the output due to unstable voltage and temperature. But if you carry out operational control of these parameters, for example, using a controller with a stabilizer function, then the block diagram shown above will be quite suitable for use in computer technology. Such a simplified power supply circuit using a pulse width modulation controller is shown in the following figure.

PWM controller, for example UC3843, it is in in this case and regulates the amplitude of changes in signals passing through the filter low frequencies, watch the video lesson below:

    This page contains several dozen electrical circuit diagrams and useful links to resources related to the topic of equipment repair. Mainly computer. Remembering how much effort and time sometimes had to be spent searching for the necessary information, a reference book or a diagram, I have collected here almost everything that I used during repairs and that was available in electronic form.

I hope this is of some use to someone.

- Directory in .chm format. The author of this file is Pavel Andreevich Kucheryavenko. Most of the source documents were taken from the website pinouts.ru - brief descriptions and pinouts of more than 1000 connectors, cables, adapters. Descriptions of buses, slots, interfaces. Not only computer equipment, but also cell phones, GPS receivers, audio, photo and video equipment, game consoles, car interfaces.

The program is designed to determine the capacitance of a capacitor by color marking (12 types of capacitors).

startcopy.ru - in my opinion, this is one of the best sites on the RuNet dedicated to the repair of printers, copiers, and multifunctional devices. You can find techniques and recommendations for fixing almost any problem with any printer.

wires:

Power supply circuits for ATX 250 SG6105, IW-P300A2, and 2 circuits of unknown origin.

NUITEK (COLORS iT) 330U power supply circuit.

Codegen 250w mod power supply circuit. 200XA1 mod. 250XA1.

Codegen 300w mod power supply circuit. 300X.

PSU diagram Delta Electronics Inc. model DPS-200-59 H REV:00.

PSU diagram Delta Electronics Inc. model DPS-260-2A.

DTK PTP-2038 200W power supply circuit.

Power supply diagram FSP Group Inc. model FSP145-60SP.

Green Tech power supply diagram. model MAV-300W-P4. Block diagrams HIPER nutrition

HPU-4K580

Power supply diagram SIRTEC INTERNATIONAL CO. LTD. HPC-360-302 DF REV:C0

Power supply diagram SIRTEC INTERNATIONAL CO. LTD. HPC-420-302 DF REV:C0

Power supply circuits INWIN IW-P300A2-0 R1.2.

INWIN IW-P300A3-1 Powerman power supply diagrams.

JNC Computer Co. LTD LC-B250ATX

JNC Computer Co. LTD. SY-300ATX power supply diagram

Presumably manufactured by JNC Computer Co. LTD. Power supply SY-300ATX. The diagram is hand-drawn, comments and recommendations for improvement.

Power supply circuits Power Master model LP-8 ver 2.03 230W (AP-5-E v1.1).

Power supply circuits Power Master model FA-5-2 ver 3.2 250W.

Maxpower PX-300W power supply circuit