College】 【weak CPU power circuit analysis and troubleshooting..

<br> <BR> all the electronic components supply is a prerequisite for the work, and most likely a bad power supply circuit unit, the main power supply circuit board CPU power, memory and chipset power supply, especially in .CPU power supply circuit of the high failure rate, here we are on the CPU power supply circuit for an analysis. .<BR> Because the CPU core voltage is relatively low and has a trend of increasingly low, ATX 12V power supply board and not directly to the CPU 5V DC power supply, it needs some high-power supply circuit to DC voltage to low DC .voltage conversion (ie, DC-DC), which is the CPU power supply converter circuits. .<BR> <BR> <BR> One, CPU power circuit <BR> 1. .CPU power supply circuit functions: <BR> motherboard CPU power supply circuit for the CPU the most important function is to provide electricity to ensure the CPU in high-frequency, high current and stable operation under working conditions. .Also, because the current CPU power consumption is very large, from low load to full load current change is very large, in order to ensure the CPU can slow down the load changes, not on the current supply will not and can not work, CPU power supply circuit .requires a very fast high-current response. .<BR> In addition, CPU power supply circuit board is also where the greatest signal strength, not handled properly will produce crosstalk effects, while the weaker signal of the digital circuit parts, so CPU power supply part of the circuit design and manufacturing requirements are usually .relatively high. .Simply put, CPU power supply part of the ultimate goal is to achieve CPU CPU power input voltage and current requirements. .<BR> <BR> 2. .CPU power circuit components: <BR> motherboard CPU power supply circuit mainly by the power management chip, inductors, FET (MOSFET tube) and the composition of electrolytic capacitors and other components. .<BR> (1) power management chip <BR> primarily responsible for identifying the power management chip CPU power amplitude, to produce short-wave moments, and promote post-stage circuit for power output. .Jin commonly used power management chips are HIP6301, IS6537, RT9237, ADP3168, KA7500, TL494 and so on. .Some of the main power management chip <BR> dual in-line chips, and some surface mount package, which is the more classic HIP630x series chip power management chip, designed by the renowned company Intersil chip design. .It supports two / three / four-phase power supply, support VRM9.0 regulate the voltage output range is 1.1V-1.85V, the interval can be adjusted to 0.025V output, the switching frequency up to 80KHz, with a power supply large ripple, the .negative characteristics of small, precise adjustments to CPU supply voltage. .The following hair HIP6301, for example, the power management chip to explain the function of each pin. .<BR> <BR> (2) inductance coil wire prince Yu <BR> inductance of ferrite cores by the wire in the ring or bar magnet made a few laps around the system, a coil, vertical and solid-state type to wait several .. .Motherboard CPU power circuit inductance coil inductor includes two types of filtering used on the current, called the filter inductance; the other is used for energy storage inductors. .Through and FET, capacitors used in conjunction to the CPU power supply. .Also, according to the characteristics of energy storage coil, the actual circuits using inductors and capacitors are usually composed of low-pass filter system to filter the high frequency clutter power supply circuit to provide clean power to the CPU current. .<BR> <BR> (3) <BR> CPU power supply filter capacitor capacitor circuit is commonly used by people often talk about "ordinary capacitor." .Capacitor in the circuit has a "direct cross every" feature, and its role includes the following aspects: First, the filtering, the majority are used in the filter circuit after the DC conversion, the use of its charge and discharge characteristics of the cooperation in the energy storage inductor ., will become a relatively smooth DC pulsed DC, in general, large-capacity capacitors for filtering low-frequency clutter, and the small capacitor filter out the effect of high-frequency clutter is better; third decoupling signal to prevent signal .crosstalk in the circuit; third signal coupling, the two circuits for dc isolation between the circuit when the signal transmission. .<BR> Single phase power supply circuits, capacitors and inductors in the specifications of the higher and the number of FET more representative of the power supply circuit for better quality. .Under normal circumstances, at the Department of SANY (Sanyo), Rubycon (Ruby), KZG capacitors is superior, the Taiwan Department of TAICON, OST, TEAPO, CAPXON film capacitors and other products can also be considered. .A small number of high-end overclocked motherboard also excellent chemical stability with solid capacitors, the complete elimination of the occurrence of the phenomenon of exploding capacitors. .<BR> <BR> (4) field-effect MOSFET <BR> celebrate pipe is the sound effect of metal oxide semiconductor transistors (MetallicOxideSemiconductorFidldEffectTransistor) short, with extremely fast switching speed, internal resistance, high input impedance, a small drive current .(0.1uA so), thermal stability, the work current, parallel and so can be a simple, very suitable for use as a switch. .CPU power supply circuit FET common, usually on both sides of the pin source, respectively (S) and gate (G), the middle of the pin for the drain (D). .<BR> FET's role in the power supply circuit in the power management chip pulse drive for continuous on-and off, and then the ATX power output of the electrical energy storage in the inductor, and then release the load. .The motherboard power supply circuit, the performance and the number of FET. .Usually determines the performance of power supply circuits. .<BR> <BR> Second, CPU power circuitry works <BR> CPU power supply circuits commonly used way of PWM switching power supply, the power management chip that work under the CPU power requirements, to the pulsing of the FET connected .control signal, and then control FET on and off, the energy stored in the inductor, and then filtered through a capacitor output voltage to the CPU. .The basic principle <BR> CPU power, when the computer is turned on, the power management chip to obtain the output ATX power supply +5 V or +12 V power supply, in order to provide CPU voltage, CPU voltage and then automatically send the voltage identification signal recognition pin .VID to the power management chip. .Power management chip voltage according to CPU's VID to issue driver control signal to control FET turn-on of both order and frequency of its output to CPU core voltage and power supply needs, provide work for the CPU power required .. .<BR> <BR> Principle above power supply is the most basic principle of all the boards, in the actual motherboard, depending on the type of work needs CPU, CPU's power supply is divided into many types, there are single-phase .power supply circuit, two-phase power supply circuit, three-phase power supply circuit, four-phase power supply circuit, the six-phase power supply circuits and multiple circuits so are several. .<BR> <BR> <BR> <BR> <BR> <BR> <BR>.