What is the power loop in the motherboard?

Power loop is an important part of the motherboard, its role is to the host power transmission of the current voltage conversion, the voltage will be converted to the CPU can accept the core voltage value, so that the CPU normal work, as well as the host power transmission of the current to plastic and filter, Filter all kinds of clutter and interference signals to ensure the stability of the computer. The main parts of the Power loop are generally located near the motherboard's CPU slots.

Linear power supply mode

This is a good many years ago the motherboard power supply, it is by changing the transistor's degree of conductivity to achieve, the transistor is equivalent to a variable resistor, connected in the power supply circuit. Because the variable resistor and the load flow through the same current, so to consume a large amount of energy and lead to heating, low voltage conversion efficiency. In particular, the linear power supply cannot be used in a power supply circuit that requires a large current. The current mode of power supply has already been eliminated.

Power supply mode of switching power supply

This is the current widely used power supply, PWM Controller IC chip to provide pulse width modulation, and emit pulse signal, so that the field-effect tube MOSFET1 and MOSFET2 rotation conduction. Choke L0 and L1 are used as energy storage inductors and are connected with the capacitor to form LC filter circuit.

Its working principle is this: when the load at both ends of the voltage vcore (such as the CPU needed voltage) to reduce, through the MOSFET FET switch function, the external power supply to the inductance to charge and achieve the required rated voltage. When the load at both ends of the voltage rise, through the MOSFET field effect tube switch role, external power supply disconnect, inductance released just filled in the energy, then the inductor becomes the power to continue to the load power. With the consumption of energy stored on the inductor, the voltage at both ends of the load begins to decrease, and the external power supply is recharged by the switching function of MOSFET field effect tube. And so on constantly charging and discharging the process of the line into a stable voltage, always make the load at both ends of the voltage will not rise and will not be lowered, which is the largest switching power supply advantages. Also is because MOSFET field effect tube work in the switch state, the conduction when the internal resistance and the cut-off leakage current is small, therefore own electricity consumption is very little, avoids the linear power supply string to be connected in the circuit the resistance part consumes the massive energy the question. This is the so-called "single-phase power circuit" working principle.

Single-phase power supply can generally provide maximum 25A of current, but now commonly used CPU already surpassed this number, the P4 processor power can reach 70-80 Watts, the working current even reaches 50A, the single-phase power supply cannot provide the reliable power, therefore the main board's power supply circuit design uses the two-phase or even the multiphase design. is a schematic diagram of two-phase power supply, it is easy to understand, is two single-phase circuit in parallel, so it can provide double current supply, theoretically more than sufficient to meet the current CPU needs. But the above is pure theory, the actual situation also need to add a lot of factors, such as switch element performance, conductor resistance, are the factors that affect vcore. The actual application of the power supply part of the efficiency problem, electricity will not be 100% conversion, the general situation of energy consumption is converted to heat emitted out, so we common any voltage regulator is always the more hot parts of the electrical components. It should be noted that the higher the temperature represents the lower the efficiency. In this way, if the conversion efficiency of the circuit is not very high, then the use of two-phase power circuit may not meet the needs of the CPU, so there are three-phase and even more phase power supply circuit. However, this also brings the motherboard wiring complications, if the wiring design is not very reasonable at this time, it will affect the stability of high-frequency work a series of problems. Currently in the market to see the mainstream motherboard products have a lot of three-phase power supply circuit, although the CPU can provide sufficient power, but due to the lack of circuit design so that the motherboard in extreme cases of stability to a certain extent limited, such as to solve this problem will inevitably be in the circuit design wiring in the greater strength, And the cost is rising.

The reason the power supply loop uses multiphase power supply is to provide a smoother current, from the control chip PWM is the kind of pulse of the square wave signal, after the LC oscillation loop shaped like a DC current, the high potential of the square wave is very short, the more the phase, the plastic out of the more near DC.

The power circuit plays a very important role in the performance of the computer and the stability of the work, and is an important performance parameter of the motherboard. In the purchase should choose mainstream manufacturers well-designed, adequate materials used in the product.