This page contains several dozen electrical circuit diagrams, and useful links for resources related to the topic of equipment repair. Mainly computer. Remembering how much effort and time sometimes had to be spent searching 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.
Utilities and reference books.
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.
Power supplies.
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.
Power supply circuits HIPER 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 Key Mouse Electronics Co Ltd model PM-230W
Block diagrams power supply 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.
PSU diagram Maxpower PX-300W
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In it you will find typical power supply diagrams for computers, both modern ATX type and already noticeably outdated ATX.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 of circuit diagrams for ATX and AT power supplies
ATX 310T, ATX-300P4-PFC, ATX-P6; Octek X25D AP-3-1 250W; Sunny ATX-230;
BESTEC ATX-300-12ES on UC3842, 3510 and A6351 chips; BESTEC ATX-400W(PFC) on ICE1PCS01, UC3842, 6848, 3510, LM358 chips
Chieftec computer power supply diagram CFT-500A-12S, CFT-560A-12S, CFT-620A-12S (CM6800G, PS222S, SG6858 or SG6848) APS-1000C, TNY278PN, CM6800TX; Chieftec 850W CFT-850G-DF; 350W GPS-350EB-101A; 350W GPS-350FB-101A; 500W GPS-500AB-A; 550W GPS-550AB-A; 650W GPS-650AB-A and Chieftec 650W CFT-650A-12B; 1000W CFT-1000G-DF and Chieftec 1200W CFT-1200G-DF; CFT-600-14CS, CFT-650-14CS, CFT-700-14CS, CFT-750-14CS on LD7550B
Chip Goal 250W, (with CG8010DX)
Codegen QORI 200xa at 350W on the SG6105 chip
Colors-It computer block diagram 300W 300U-FNM (sg6105 and sg6848); 330W - 330U PWM SG6105 duty station on TDA865; 330U IW-P300A2-0 R1.2 sg6105; 330U PWM SG6105 and duty station M605; 340W - 340U PWM SG6105; 350U-SCE- KA339, M605, 3842; 350-FCH PWM 3842, LM339 and M605; 340U SG6105 and 5H0165R; 400U SG6105 and 5H0165R; 400PT, 400U SCH 3842, LM339 and M605; 500T SG6105 and 5H0165R; 600PT(ATX12V-13), WT7525, 3B0365
ComStars 400W KT-400EX-12A1 on UC3543A circuit
CWT PUH400W
Delta Electronics circuit diagram of a computer power supply DPS-210EP, DPS-260-2A 260W on microassemblies NE556, PQ05RF11, ML4824-1, LM358, LM339D, PQ30R21; DPS-470 AB A 500W, APFC and PWM DNA1005A or DNA1005;
DELUX ATX-350W P4 on AZ7500BP and LP7510 circuit
FSP Epsilon 600W FX600-GLN duty circuit, assembled on the FSDM0265R IC; FSP145-60SP KA3511, duty room KA1N0165R; FSP250-50PLA, APFC on CM6800, field effect transistors STP12NM50, TOP243Y, control PS223; FSP ATX-350PNR DM311 and main PWM FSP3528; FSP ATX-300PAF and ATX-350 on DA311; 350W FSP350-60THA-P And 460W FX500-A FSP3529Z (similar to SG6105; ATX-400 400W, DM311; ATX-400PNF,; OPS550-80GLN, APFC on field-effect transistors 20N60C3, duty on DM311; OPS550-80GLN,APFC+PWM control module on CM6800G; Epsilon 600W FX600-GLN(scheme); ATX-300GTF on field truck 02N60
Green Tech circuit diagram of a 300W computer power supply model MAV-300W-P4 on a TL494CN and WT7510 chip
Hiper HPU-4S425-PU 425W APFC, based on CM6805, VIPer22A, LM393, PS229 chips
iMAC G5 A1058, APFC on 4863G, duty station on TOP245YN, main power supply on 3845B
J.N.C. 250W lc-b250 atx
Krauler ATX-450 450W (with TL3845, LD7660, WT7510)
LWT 2005 on LM339N chip
M-Tech 450W KOB-AP4450XA microassembly SG6105Z
Maxpower PX-300W chip SG6105D
Microlab circuit diagram of a computer power supply 420W, on WT7510, PWM TL3842 duty station - 5H0165R; M-ATX-420W based on UC3842, supervisor 3510 and LM393
PowerLink 300W LPJ2-18 on LPG-899 microassembly
Powerman IP-P550DJ2-0, 350W IP-P350AJ, 350W IP-P350AJ2-0 ver.2.2 on supervisor W7510, 450W IP-S450T7-0, 450W IP-S450T7-0 rev:1.3 (3845, WT7510 and A6259H)
Power Master 230W model LP-8, 250W FA-5-2, 250W AP-3-1, PM30006-02 ATX 300W
Power Mini P4,Model PM-300W. Main micro assembly SG6105
Both 230 and 250 watt power supplies are based on the very popular TL494 chip. The video repair instructions tell you how to troubleshoot and safety precautions when repairing any switching power supplies, which include computer ones.
SevenTeam ST-200HRK (IC: LM339, UTC51494, UC3843AN)
ShenShon circuit diagram of a computer power supply 400W model SZ-400L and 450W model SZ450L, duty station on C3150, AT2005; 350w on AT2005, aka WT7520, or LPG899
Sparkman SM-400W on KA3842A, WT7510 circuit
SPS: SPS-1804-2(M1) and SPS-1804E
power unit personal computer- used to supply power to all components and components 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 a powerful fan located at the bottom. There is a socket on the rear panel for connecting network cable and a button to turn off the power supply, but on cheap Chinese modifications it may not be present. From the opposite side comes a huge pile of wires 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 AC network; 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, no sound signals, fans do not spin. In other cases of malfunction, the motherboard does not start. At the same time, the fans spin, the indication lights up, the drives show signs of life and hard drive, 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 principle of operation is based on the use of push-pull mode. Stabilization of the device's output parameters is carried out using control signals.
Pulse sources often use the well-known TL494 PWM controller chip, 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. It performs the main work in a computer power supply; it is converting the current to the required values and galvanic isolation of the circuit. Next alternating voltage, from the transformer windings, follows to another converter, consisting of semiconductor diodes, voltage equalizing, and 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, in this case it regulates the amplitude of changes in signals passing through the filter low frequencies, watch the video lesson below:
Utilities and reference books.
- 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 and other equipment.The program is designed to determine the capacitance of a capacitor by color marking (12 types of capacitors).
Database on transistors in Access format.
Power supplies.
Contact table for the 24-pin ATX power supply connector (ATX12V) with wire ratings and color coding
| Comte | Designation | Color | Description | |
|---|---|---|---|---|
| 1 | 3.3V | Orange | +3.3 VDC | |
| 2 | 3.3V | Orange | +3.3 VDC | |
| 3 | COM | Black | Earth | |
| 4 | 5V | Red | +5 VDC | |
| 5 | COM | Black | Earth | |
| 6 | 5V | Red | +5 VDC | |
| 7 | COM | Black | Earth | |
| 8 | PWR_OK | Grey | Power Ok - All voltages are within normal limits. This signal is generated when the power supply is turned on and is used to reset the system board. | |
| 9 | 5VSB | Violet | +5 VDC Standby voltage | |
| 10 | 12V | Yellow | +12 VDC | |
| 11 | 12V | Yellow | +12 VDC | |
| 12 | 3.3V | Orange | +3.3 VDC | |
| 13 | 3.3V | Orange | +3.3 VDC | |
| 14 | -12V | Blue | -12 VDC | |
| 15 | COM | Black | Earth | |
| 16 | /PS_ON | Green | Power Supply On. To turn on the power supply, you need to short-circuit this contact to ground (with a black wire). | |
| 17 | COM | Black | Earth | |
| 18 | COM | Black | Earth | |
| 19 | COM | Black | Earth | |
| 20 | -5V | White | -5 VDC (this voltage is used very rarely, mainly to power old expansion cards.) | |
| 21 | +5V | Red | +5 VDC | |
| 22 | +5V | Red | +5 VDC | |
| 23 | +5V | Red | +5 VDC | |
| 24 | COM | Black | Earth |
Power supply diagram ATX-300P4-PFC (ATX-310T 2.03).
ATX-P6 power supply diagram.
API4PC01-000 400w power supply diagram manufactured by Acbel Politech Ink.
Power supply diagram Alim ATX 250Watt SMEV J.M. 2002.
Typical diagram of a 300W power supply with notes on the functional purpose of individual parts of the circuit.
Typical circuit of a 450W power supply with the implementation of active power factor correction (PFC) of modern computers.
API3PCD2-Y01 450w power supply diagram manufactured by ACBEL ELECTRONIC (DONGGUAN) CO. LTD.
Power supply circuits for ATX 250 SG6105, IW-P300A2, and 2 circuits of unknown origin.
NUITEK (COLORS iT) 330U (sg6105) power supply circuit.
NUITEK (COLORS iT) 330U power supply circuit on the SG6105 chip.
NUITEK (COLORS iT) 350U SCH power supply circuit.
NUITEK (COLORS iT) 350T power supply circuit.
NUITEK (COLORS iT) 400U power supply circuit.
NUITEK (COLORS iT) 500T power supply circuit.
PSU circuit NUITEK (COLORS iT) ATX12V-13 600T (COLORS-IT - 600T - PSU, 720W, SILENT, ATX)
PSU diagram CHIEFTEC TECHNOLOGY GPA500S 500W Model GPAxY-ZZ SERIES.
Codegen 250w mod power supply circuit. 200XA1 mod. 250XA1.
Codegen 300w mod power supply circuit. 300X.
PSU circuit CWT Model PUH400W.
PSU diagram Delta Electronics Inc. model DPS-200-59 H REV:00.
PSU diagram Delta Electronics Inc. model DPS-260-2A.
Power supply diagram DTK Computer model PTP-2007 (aka MACRON Power Co. ATX model 9912)
DTK PTP-2038 200W power supply circuit.
EC model 200X power supply circuit.
Power supply diagram FSP Group Inc. model FSP145-60SP.
PSU standby power supply diagram FSP Group Inc. model ATX-300GTF.
PSU standby power supply diagram FSP Group Inc. model FSP Epsilon FX 600 GLN.
Green Tech power supply diagram. model MAV-300W-P4.
Power supply circuits HIPER HPU-4K580. The archive contains a file in SPL format (for the sPlan program) and 3 files in GIF format - simplified circuit diagrams: Power Factor Corrector, PWM and power circuit, autogenerator. If you have nothing to view .spl files, use diagrams in the form of pictures in .gif format - they are the same.
Power supply circuits INWIN IW-P300A2-0 R1.2.
INWIN IW-P300A3-1 Powerman power supply diagrams.
The most common malfunction of Inwin power supplies, the diagrams of which are given above, is the failure of the standby voltage generation circuit +5VSB (standby voltage). As a rule, it is necessary to replace the electrolytic capacitor C34 10uF x 50V and the protective zener diode D14 (6-6.3 V). In the worst case, R54, R9, R37, microcircuit U3 (SG6105 or IW1688 (complete analogue of SG6105)) are added to the faulty elements. For the experiment, I tried installing C34 with a capacity of 22-47 uF - perhaps this will increase the reliability of the duty station.
Power supply diagram Powerman IP-P550DJ2-0 (IP-DJ Rev:1.51 board). The standby voltage generation circuit in the document is used in many other models of Power Man power supplies (for many power supplies with a power of 350W and 550W, the differences are only in the ratings of the elements).
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 Key Mouse Electroniks Co Ltd model PM-230W
Power supply circuits L&C Technology Co. model LC-A250ATX
LWT2005 power supply circuits on the KA7500B and LM339N chip
M-tech KOB AP4450XA power supply circuit.
PSU diagram MACRON Power Co. model ATX 9912 (aka DTK Computer model PTP-2007)
PSU diagram Maxpower PX-300W
PSU diagram Maxpower PC ATX SMPS PX-230W ver.2.03
Power supply diagrams PowerLink model LP-J2-18 300W.
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.
Microlab 350W power supply circuit
Microlab 400W power supply circuit
Powerlink LPJ2-18 300W power supply circuit
PSU circuit Power Efficiency Electronic Co LTD model PE-050187
Rolsen ATX-230 power supply circuit
SevenTeam ST-200HRK power supply diagram
PSU circuit SevenTeam ST-230WHF 230Watt
SevenTeam ATX2 V2 power supply circuit
An integral part of every computer is power supply unit (PSU). It is just as important as the rest of the computer. At the same time, purchasing a power supply is quite rare, since a good power supply can provide power to several generations of systems. Taking all this into account, the purchase of a power supply must be taken very seriously, since the fate of the computer is directly dependent on the performance of the power supply.
The main purpose of the power supply issupply voltage generation, which is necessary for the functioning of all PC blocks. The main component supply voltages are:
- +12V
- +3.3V
There are also additional voltages:
- −12V
To implement galvanic isolation It is enough to make a transformer with the necessary windings. But to power a computer you need a considerable power, especially for modern PCs. For computer power supply it would be necessary to manufacture a transformer that would not only be large in size, but also weigh a lot. However, as the frequency of the transformer supply current increases, to create the same magnetic flux, fewer turns and a smaller cross-section of the magnetic core are required. In power supplies built on the basis of a converter, the frequency of the transformer supply voltage is 1000 or more times higher. This allows you to create compact and lightweight power supplies.
The simplest pulse power supply
Consider a block diagram of a simple switching power supply, which underlies all switching power supplies.
Block diagram of a switching power supply.
The first block implements conversion of AC network voltage to DC. Such converter consists of a diode bridge that rectifies alternating voltage and a capacitor that smoothes out ripples of the rectified voltage. This box also contains additional elements: mains voltage filters from pulse generator ripples and thermistors to smooth out the current surge at the moment of switching on. However, these elements may be omitted in order to save on cost.
Next block - pulse generator, which generates pulses at a certain frequency that supply primary winding transformer. The frequency of generating pulses of different power supplies is different and ranges from 30 to 200 kHz. The transformer performs the main functions of the power supply: galvanic isolation from the network and reducing the voltage to the required values.
The alternating voltage received from the transformer is converted by the next block into direct voltage. The block consists of voltage rectifying diodes and a ripple filter. In this block, the ripple filter is much more complex than in the first block and consists of a group of capacitors and a choke. In order to save money, manufacturers can install small capacitors, as well as chokes with low inductance.
First pulse block nutrition represented push-pull or single-cycle converter. Push-pull means that the generation process consists of two parts. In such a converter, two transistors open and close in turn. Accordingly, in a single-ended converter one transistor opens and closes. Circuits of push-pull and single-cycle converters are presented below.
.
Let's take a closer look at the elements of the circuit:
X2 - connector power supply circuit.
X1 is the connector from which the output voltage is removed.
R1 is a resistance that sets the initial small bias on the keys. It is necessary for a more stable start of the oscillation process in the converter.
R2 is a resistance that limits the base current on the transistors; this is necessary to protect the transistors from burning out.
TP1 - The transformer has three groups of windings. The first output winding generates the output voltage. The second winding serves as a load for the transistors. The third generates the control voltage for the transistors.
At the initial moment of turning on the first circuit, the transistor is slightly open, since a positive voltage is applied to the base through resistor R1. A current flows through the slightly open transistor, which also flows through winding II of the transformer. The current flowing through the winding creates a magnetic field. The magnetic field creates voltage in the remaining windings of the transformer. As a result, a positive voltage is created on winding III, which opens the transistor even more. The process continues until the transistor reaches saturation mode. The saturation mode is characterized by the fact that as the applied control current to the transistor increases, the output current remains unchanged.
Since the voltage in the windings is generated only in the event of a change in the magnetic field, its increase or decrease, the absence of an increase in the current at the output of the transistor will, therefore, lead to the disappearance of the emf in windings II and III. A voltage loss in winding III will lead to a decrease in the degree of opening of the transistor. And the output current of the transistor will decrease, therefore, the magnetic field will decrease. Decreasing the magnetic field will create a voltage of opposite polarity. The negative voltage in winding III will begin to close the transistor even more. The process will continue until the magnetic field completely disappears. When the magnetic field disappears, the negative voltage in winding III will also disappear. The process will begin to repeat itself again.
A push-pull converter works on the same principle, but the difference is that there are two transistors, and they open and close in turn. That is, when one is open, the other is closed. The push-pull converter circuit has the great advantage of using the entire hysteresis loop of the magnetic conductor of the transformer. Using only one section of the hysteresis loop or magnetizing in only one direction leads to many undesirable effects that reduce the efficiency of the converter and degrade its performance. Therefore, a push-pull converter circuit with a phase-shifting transformer is generally used everywhere. In circuits where simplicity, small dimensions, and low power are needed, a single-cycle circuit is still used.
ATX form factor power supplies without power factor correction
The converters discussed above, although complete devices, are inconvenient to use in practice. The converter frequency, output voltage and many other parameters “float”, changing depending on changes in: supply voltage, converter output load and temperature. But if the keys are controlled by a controller that could carry out stabilization and various additional features, then you can use the circuit to power the devices. The power supply circuit using a PWM controller is quite simple, and, in general, is a pulse generator built on a PWM controller.
PWM – pulse width modulation. It allows you to adjust the amplitude of the signal passed through the LPF (low pass filter) by changing the duration or duty cycle of the pulse. The main advantages of PWM are the high efficiency of power amplifiers and great application possibilities.
This power supply circuit has low power and uses a field-effect transistor as a switch, which allows you to simplify the circuit and get rid of additional elements required to control transistor switches. IN power supplies high power PWM controller has controls (“Driver”) for the output switch. IGBT transistors are used as output switches in high-power power supplies.
The mains voltage in this circuit is converted into direct voltage and is supplied through a switch to the first winding of the transformer. The second winding serves to power the microcircuit and generate voltage feedback. The PWM controller generates pulses with a frequency that is set by an RC circuit connected to pin 4. The pulses are fed to the input of the switch, which amplifies them. The duration of the pulses varies depending on the voltage on leg 2.
Let's consider a real ATX power supply circuit. It has many more elements and additional devices are present in it. The power supply circuit is conventionally divided into main parts by red squares.
ATX power supply circuit with a power of 150–300 W
To power the controller chip, as well as generate the standby voltage +5, which is used by the computer when it is turned off, there is another converter in the circuit. In the diagram it is designated as block 2. As you can see, it is made according to the circuit of a single-cycle converter. The second block also contains additional elements. Basically, these are chains for absorbing voltage surges that are generated by the converter transformer. Chip 7805 - voltage stabilizer forms standby voltage+5V from the rectified voltage of the converter.
Often, low-quality or defective components are installed in the standby voltage generation unit, which causes the frequency of the converter to decrease to the audio range. As a result, a squeaking sound is heard from the power supply.
Since the power supply is powered from an AC network voltage 220V, and the converter needs DC voltage power, the voltage needs to be converted. The first block rectifies and filters alternating mains voltage. This block also contains a filter against interference generated by the power supply itself.
The third block is the TL494 PWM controller. It carries out all the main functions of the power supply. Protects the power supply from short circuits, stabilizes output voltages and generates a PWM signal to control transistor switches that are loaded on the transformer.
The fourth block consists of two transformers and two groups of transistor switches. The first transformer generates the control voltage for the output transistors. Since the TL494 PWM controller generates a low power signal, the first group of transistors amplifies this signal and passes it to the first transformer. The second group of transistors, or output ones, are loaded onto the main transformer, which generates the main supply voltages. This one is more complex circuit control of output switches is used due to the complexity of controlling bipolar transistors and protecting the PWM controller from high voltage.
The fifth block consists of Schottky diodes, which rectify the output voltage of the transformer, and a low-pass filter (LPF). The low-pass filter consists of electrolytic capacitors of significant capacity and chokes. At the output of the low-pass filter there are resistors that load it. These resistors are necessary to ensure that the power supply capacity does not remain charged after turning off. There are also resistors at the output of the mains voltage rectifier.
The remaining elements not circled in the block are chains and form “ service signals" These chains carry out the work of protecting the power supply from short circuit or monitoring the health of output voltages.
Now let's see how to printed circuit board 200 W power supply elements are located. The picture shows:
Capacitors that filter output voltages.
Place of unsoldered output voltage filter capacitors.
Inductors that filter the output voltages. The larger coil not only plays the role of a filter, but also acts as a ferromagnetic stabilizer. This allows you to slightly reduce voltage imbalances when the load of different output voltages is uneven.
WT7520 PWM stabilizer chip.
A radiator on which Schottky diodes are installed for voltages of +3.3V and +5V, and for voltages of +12V there are ordinary diodes. It should be noted that often, especially in older power supplies, additional elements are placed on the same radiator. These are voltage stabilization elements +5V and +3.3V. In modern power supplies, only Schottky diodes for all main voltages or field-effect transistors, which are used as a rectifying element, are placed on this radiator.
The main transformer, which generates all voltages, as well as galvanic isolation from the network.
A transformer that generates control voltages for the output transistors of the converter.
Converter transformer generating standby voltage +5V.
The radiator on which the output transistors of the converter are located, as well as the transistor of the converter that generates the standby voltage.
Mains voltage filter capacitors. There don't have to be two of them. To form a bipolar voltage and form a midpoint, two capacitors of equal capacity are installed. They divide the rectified mains voltage in half, thereby forming two voltages of different polarity, connected at a common point. In single-supply circuits there is only one capacitor.
Network filter elements against harmonics (interference) generated by the power supply.
Diode bridge diodes that rectify AC mains voltage.
Power supply 350 W arranged equivalently. What immediately catches your eye is the large board size, larger radiators and larger converter transformer.
Output voltage filter capacitors.
A radiator that cools the diodes that rectify the output voltage.
PWM controller AT2005 (analogous to WT7520), which performs voltage stabilization.
The main transformer of the converter.
A transformer that generates control voltage for output transistors.
Standby voltage converter transformer.
A radiator that cools the output transistors of the converters.
Mains voltage filter against power supply interference.
Diode bridge diodes.
Mains voltage filter capacitors.
The considered circuit has been used in power supplies for a long time and is now sometimes found.
ATX format power supplies with power factor correction
In the considered circuits, the network load is a capacitor connected to the network through a diode bridge. The capacitor is charged only if the voltage across it is less than the mains voltage. As a result, the current is pulsed in nature, which has many disadvantages.
We list these disadvantages:
- currents introduce higher harmonics (interference) into the network;
- large amplitude of current consumption;
- significant reactive component in the consumption current;
- mains voltage is not used during the entire period;
- The efficiency of such circuits is of little importance.
New power supplies have an improved modern circuit, it has one more additional block - power factor corrector (PFC). It improves the power factor. Or more in simple language eliminates some of the disadvantages of the mains voltage bridge rectifier.
S=P+jQ
Total Power Formula
Power factor (PF) characterizes how much of the total power there is an active component and how much is reactive. In principle, one can say, why take into account reactive power, it is imaginary and has no benefit.
Let's say we have a certain device, a power supply, with a power factor of 0.7 and a power of 300 W. It can be seen from the calculations that our power supply has a total power (the sum of reactive and active power) greater than that indicated on it. And this power should be provided by a 220V power supply. Although this power is not useful (even the electricity meter does not record it), it still exists.
That is, the internal elements and network wires should be rated for 430 watts, not 300 watts. Imagine a case where the power factor is 0.1... Because of this, GORSET prohibits the use of devices with a power factor of less than 0.6, and if such are detected, a fine is imposed on the owner.
Accordingly, the campaigns developed new power supply circuits that had PFC. Initially, a high-inductance inductor connected at the input was used as a PFC; such a power supply is called a power supply with PFC or passive PFC. Such a power supply has an increased KM. To achieve the desired CM, it is necessary to equip power supplies with a large choke, since the input resistance of the power supply is capacitive in nature due to the capacitors installed at the output of the rectifier. Installing a choke significantly increases the mass of the power supply, and increases the KM to 0.85, which is not so much.
The picture shows the company's power supply 400W FSP with passive power factor correction. It contains the following elements:
- Output voltage ripple filter capacitors.
Rectified mains voltage filter capacitors.
Throttle performing power factor correction.
Main converter transformer.
Transformer that controls the keys.
Auxiliary converter transformer (standby voltage).
Mains voltage filters against power supply ripples.
A radiator on which the output transistor switches are installed.
A radiator on which diodes are installed that rectify the alternating voltage of the main transformer.
Fan speed control board.
A board on which the FSP3528 PWM controller is installed (analogous to KA3511).
Group stabilization choke and output voltage ripple filter elements.
Due to the low efficiency of the passive PFC, a new PFC circuit was introduced into the power supply, which is built on the basis of a PWM stabilizer loaded onto an inductor. This circuit brings many advantages to the power supply:
- extended operating voltage range;
- it became possible to significantly reduce the capacitance of the mains voltage filter capacitor;
- significantly increased CM;
- reducing the weight of the power supply;
- increasing the efficiency of the power supply.
There are also disadvantages to this scheme - these are decrease in power supply reliability and incorrect work with some uninterruptible power supplies I when switching operating modes battery / network. The incorrect operation of this circuit with a UPS is caused by the fact that the mains voltage filter capacitance in the circuit has significantly decreased. At the moment when the voltage disappears for a short time, the PFC current required to maintain the voltage at the PFC output increases greatly, as a result of which short circuit protection (short circuit) in the UPS is triggered.
If you look at the circuit, it is a pulse generator, which is loaded onto the inductor. The mains voltage is rectified by a diode bridge and supplied to the switch, which is loaded by inductor L1 and transformer T1. A transformer is introduced to provide feedback from the controller to the key. The voltage from the inductor is removed using diodes D1 and D2. Moreover, the voltage is removed alternately using diodes, either from the diode bridge or from the inductor, and charges the capacitors Cs1 and Cs2. Key Q1 opens and the required amount of energy is accumulated in throttle L1. The amount of accumulated energy is regulated by the duration open state key The more energy accumulated, the more voltage the inductor will produce. After the key is turned off, the accumulated energy is released by the inductor L1 through the diode D1 to the capacitors.
This operation makes it possible to use the entire sinusoid of the alternating voltage of the network, in contrast to circuits without PFC, and also to stabilize the voltage supplying the converter.
IN modern schemes power supplies are often used dual channel PWM controllers. One microcircuit operates both the converter and the PFC. As a result, the number of elements in the power supply circuit is significantly reduced.
Let's consider the circuit of a simple 12V power supply using a two-channel PWM controller ML4819. One part of the power supply generates a constant stabilized voltage+380V. The other part is a converter that generates a constant stabilized voltage of +12V. The PFC consists, as in the case considered above, of switch Q1, inductor L1 of feedback transformer T1 loaded on it. Diodes D5, D6 charge capacitors C2, ° C3, ° C4. The converter consists of two switches Q2 and Q3, loaded onto transformer T3. The pulse voltage is rectified by diode assembly D13 and filtered by inductor L2 and capacitors C16, ° C18. Using cartridge U2, the output voltage control voltage is generated.
Let's consider the design of a power supply that has an active PFC:
- Current protection control board;
- A choke that performs the role of both a voltage filter +12V and +5V, and a group stabilization function;
- Voltage filter choke +3.3V;
- A radiator on which rectifier diodes of output voltages are located;
- Main converter transformer;
- Transformer that controls the keys of the main converter;
- Auxiliary converter transformer (forming standby voltage);
- Power factor correction controller board;
- Radiator, cooling diode bridge and main converter switches;
- Line voltage filters against interference;
- Power factor corrector choke;
- Mains voltage filter capacitor.
Design features and types of connectors
Let's consider types of connectors, which may be present on the power supply. On the back of the power supply there is a connector for connecting network cable and a switch. Previously, next to the power cord connector, there was also a connector for connecting the monitor's network cable. Optionally, other elements may be present:
- indicators of mains voltage or power supply operating status
- fan operating mode control buttons
- button for switching input mains voltage 110 / 220V
- USB ports built into the unit USB power supply hub
- other.
Fans that extract air from the power supply are increasingly placed on the rear wall. Increasingly, the fan is placed at the top of the power supply due to the larger space for installing the fan, which allows you to install a large and quiet active cooling element. Some power supplies even have two fans installed, both on top and on the back.
Coming out from the front wall wire with motherboard power connector. In some modular power supplies, it, like other wires, is connected through a connector. The figure below shows.
You can notice that each voltage has its own wire color:
- Yellow color - +12 V
- Red color - +5 V
- Orange color - +3.3V
- Black color - common or ground
For other voltages, wire colors may vary from manufacturer to manufacturer.
The figure does not show additional power connectors for video cards, since they are similar to the additional power connectors for the processor. There are also other types of connectors that are found in branded computers from DelL, Apple and others.
Electrical parameters and characteristics of power supplies
The power supply has many electrical parameters, most of which are not noted in the data sheet. On the side sticker of the power supply, only a few basic parameters are usually marked - operating voltages and power.
Power supply power
Power is often indicated on the label in large font. The power of the power supply characterizes how much electrical energy it can supply to the devices connected to it (motherboard, video card, hard drive, etc.).
In theory, it is enough to sum up the consumption of the components used and select a power supply with a little more power for reserve. For power calculation These recommendations are quite suitable in the video card passport, if any, processor thermal package, etc.
But in reality, everything is much more complicated, because the power supply produces different voltages - 12V, 5V, −12V, 3.3V, etc. Each voltage line is designed for its own power. It was logical to think that this power is fixed, and their sum is equal to the power of the power supply. But the power supply contains one transformer to generate all these voltages used by the computer (except for the standby voltage +5V). True, it is rare, but you can still find a power supply with two separate transformers, but such power supplies are expensive and are most often used in servers. Conventional ATX power supplies have one transformer. Because of this, the power of each voltage line can float: it increases if other lines are lightly loaded, and decreases if other lines are heavily loaded. Therefore, the maximum power of each line is often written on power supplies, and as a result, if they are summed up, the power will be even greater than the actual power of the power supply. Thus, the manufacturer can confuse the consumer, for example, by declaring too high a rated power that the power supply is not capable of providing.
Please note that if your computer has Insufficient power supply, this will cause the devices to not operate correctly ( Freezes, reboots, clicking heads hard drive ), to the point of impossibility turning on the computer. And if the PC has a motherboard installed that is not designed for the power of the components that are installed on it, then the motherboard often functions normally, but over time the power connectors burn out due to their constant heating and oxidation.
Standards and certificates
When purchasing a power supply, first of all you need to look at the availability of certificates and its compliance with modern international standards. The following standards can most often be found on power supplies:
- CCC - China Certificate of Safety, Electromagnetic and Environmental Compliance
RoHS, WEEE – does not contain harmful substances
UL, cUL – certificate of compliance with its technical specifications, as well as safety requirements for built-in electrical appliances
CE - a certificate that shows that the power supply meets the strictest requirements of the European Directives
ISO – international quality certificate
CB - international certificate of compliance with its technical characteristics
FCC - Electromagnetic interference (EMI) and radio frequency interference (RFI) compliance from the power supply
TUV - certificate of compliance with the requirements of the international standard EN ISO 9001:2000
There are also computer standards of the ATX form factor, which define the dimensions, design and many other parameters of the power supply, including permissible voltage deviations under load. Today there are several versions of the ATX standard:
- ATX 1.3 Standard
- ATX 2.0 Standard
- ATX 2.2 Standard
- ATX 2.3 Standard
The difference between the versions of ATX standards mainly concerns the introduction of new connectors and new requirements for the power supply lines of the power supply.
Recommendations for choosing a power supply
When does it occur need to buy a new power supply ATX, then first you need to determine the power that is needed to power the computer in which this power supply will be installed. To determine it, it is enough to sum up the power of the components used in the system, for example, using a special calculator. If this is not possible, then we can proceed from the rule that for an average computer with one gaming video card, a power supply with a power of 500–600 watts is sufficient.
Considering that most of the parameters of a power supply can only be found out by testing it, the next step we strongly recommend that you familiarize yourself with the tests and reviews of possible contenders - power supply models, which are available in your region and satisfy your needs at least in terms of power provided. If this is not possible, then you need to choose according to the power supply’s compliance with modern standards (the higher the number, the better), and it is desirable to have an APFC circuit in the power supply. When purchasing a power supply, it is also important to turn it on, if possible right at the place of purchase or immediately upon arriving home, and monitor how it works so that the power source does not make squeaks, hums or other extraneous noise.
In general, you need to choose a power supply that is powerful, well made, with good stated and real electrical parameters, and will also be convenient to use and quiet during operation, even with high load at him. And under no circumstances should you save a few dollars when purchasing a power supply. Remember that the stability, reliability and durability of the entire computer mainly depends on the operation of this device.
If your computer's power supply fails, do not rush to get upset; as practice shows, in most cases repairs can be done on your own. Before moving directly to the methodology, we will consider the block diagram of the power supply and provide a list of possible faults; this will significantly simplify the task.
Block diagram
The figure shows an image of a block diagram typical for switching power supply system units.
Designations indicated:
- A – surge protector unit;
- B – low-frequency rectifier with a smoothing filter;
- C – auxiliary converter stage;
- D – rectifier;
- E – control unit;
- F – PWM controller;
- G – cascade of the main converter;
- H – high-frequency rectifier equipped with a smoothing filter;
- J – power supply cooling system (fan);
- L – output voltage control unit;
- K – overload protection.
- +5_SB – standby power mode;
- P.G. – information signal, sometimes designated as PWR_OK (necessary for the motherboard to start);
- PS_On – signal controlling the start of the power supply.
Pinout of the main PSU connector
To carry out repairs, we will also need to know the pinout of the main power connector, it is shown below.
To start the power supply, you need to connect the green wire (PS_ON#) to any black zero wire. This can be done using a regular jumper. Note that some devices may have color markings that differ from the standard ones; as a rule, unknown manufacturers from the Middle Kingdom are guilty of this.
PSU load
It is necessary to warn that without load significantly reduces their service life and can even cause failure. Therefore, we recommend assembling a simple load block; its diagram is shown in the figure.
It is advisable to assemble the circuit using resistors of the PEV-10 brand, their ratings are: R1 - 10 Ohms, R2 and R3 - 3.3 Ohms, R4 and R5 - 1.2 Ohms. Cooling for the resistances can be made from aluminum channel.
Connect as a load during diagnostics motherboard or, as some “craftsmen” advise, HDD and CD drives are undesirable, since a faulty power supply can damage them.
List of possible faults
We list the most common malfunctions characteristic of switching power supply system units:
- The mains fuse blows;
- +5_SB (standby voltage) is absent, and also more or less than permissible;
- the voltage at the output of the power supply (+12 V, +5 V, 3.3 V) is not normal or missing;
- no P.G. signal (PW_OK);
- The power supply does not turn on remotely;
- The cooling fan does not rotate.
Test method (instructions)
After the power supply is removed from the system unit and disassembled, first of all, it is necessary to inspect it to detect damaged elements (darkening, changed color, loss of integrity). Note that in most cases, replacing the burnt part will not solve the problem; you will need to check the piping.
If none are found, proceed to the following algorithm of actions:
- check the fuse. You should not trust a visual inspection, but it is better to use a multimeter in dial mode. The reason why the fuse has blown may be a breakdown of the diode bridge, a key transistor, or a malfunction of the unit responsible for the standby mode;
- checking the disk thermistor. Its resistance should not exceed 10 Ohms; if it is faulty, we strongly advise against installing a jumper instead. The pulse current that occurs during the charging of capacitors installed at the input can cause breakdown of the diode bridge;
- We test diodes or a diode bridge on the output rectifier; there should be no open circuit or short circuit in them. If a malfunction is detected, the capacitors and key transistors installed at the input should be checked. The alternating voltage supplied to them as a result of the breakdown of the bridge, with a high probability, caused these radio components to fail;
- checking electrolytic type input capacitors begins with inspection. The geometry of the body of these parts must not be violated. After this, the capacitance is measured. It is considered normal if it is not less than declared, and the discrepancy between the two capacitors is within 5%. Also, the equalizing resistances sealed in parallel with the input electrolytes must be checked;
- testing of key (power) transistors. Using a multimeter, we check the base-emitter and base-collector junctions (the technique is the same as for).
If a faulty transistor is found, then before soldering in a new one, it is necessary to test its entire wiring, consisting of diodes, low-resistance resistances and electrolytic capacitors. We recommend replacing the latter with new ones that have a larger capacity. Good results are obtained by shunting electrolytes using 0.1 μF ceramic capacitors;
- Checking output diode assemblies (Schottky diodes) using a multimeter, as practice shows, the most typical malfunction for them is a short circuit;
- checking electrolytic type output capacitors. As a rule, their malfunction can be detected by visual inspection. It manifests itself in the form of changes in the geometry of the radio component housing, as well as traces of electrolyte leakage.
It is not uncommon for an apparently normal capacitor to turn out to be unusable when tested. Therefore, it is better to test them with a multimeter that has a capacitance measurement function, or use a special device for this.
Video: correct repair of an ATX power supply.
https://www.youtube.com/watch?v=AAMU8R36qyE
Note that non-working output capacitors are the most common fault in computer power supplies. In 80% of cases, after replacing them, the performance of the power supply is restored;
- The resistance between the outputs and zero is measured; for +5, +12, -5 and -12 volts this indicator should be in the range from 100 to 250 Ohms, and for +3.3 V in the range of 5-15 Ohms.
Refinement of power supply
In conclusion, we will give some tips on improving the power supply, which will make its operation more stable:
- in many inexpensive units, manufacturers install two-amp rectifier diodes; they should be replaced with more powerful ones (4-8 amperes);
- Schottky diodes on the +5 and +3.3 volt channels can also be installed more powerful, but they must have an acceptable voltage, the same or greater;
- It is advisable to replace the output electrolytic capacitors with new ones with a capacity of 2200-3300 μF and a rated voltage of at least 25 volts;
- It happens that instead of a diode assembly, diodes soldered together are installed on the +12 volt channel; it is advisable to replace them with a Schottky diode MBR20100 or similar;
- if 1 µF capacitances are installed in the key transistors, replace them with 4.7-10 µF, designed for a voltage of 50 volts.
Such a minor modification will significantly extend the life of the computer power supply.