Voltage regulator module for an Intel Xeon 500 MHz processor

A voltage regulator module (VRM), sometimes called processor power module (PPM), is a

buck converter A buck converter (step-down converter) is a DC-to-DC power converter which steps down voltage (while stepping up current) from its input (supply) to its output (load). It is a class of switched-mode power supply (SMPS) typically containing at ...

that provides

microprocessor A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...

and

chipset In a computer system, a chipset is a set of electronic components An electronic component is any basic discrete device or physical entity in an electronic system used to affect electrons or their associated fields. Electronic components are ...

the appropriate supply voltage, converting , or to lower voltages required by the devices, allowing devices with different supply voltages be mounted on the same motherboard. On

personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

(PC) systems, the VRM is typically made up of

power MOSFET A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices, such as an insulated-gate bipolar transistor (IG ...

devices.

Overview

Most voltage regulator module implementations are soldered onto the

motherboard A motherboard (also called mainboard, main circuit board, mb, mboard, backplane board, base board, system board, logic board (only in Apple computers) or mobo) is the main printed circuit board (PCB) in general-purpose computers and other expand ...

. Some processors, such as Intel Haswell and Ice Lake CPUs, feature some voltage regulation components on the same CPU package, reduce the VRM design of the motherboard; such a design brings certain levels of simplification to complex voltage regulation involving numerous CPU supply voltages and dynamic powering up and down of various areas of a CPU. A voltage regulator integrated on-package or on-die is usually referred to as ''fully integrated voltage regulator'' (''FIVR'') or simply an ''integrated voltage regulator'' (''IVR''). Voltage regulator module on a computer motherboard

Voltage regulator module on a computer motherboard

Most modern CPUs require less than , as

CPU design Processor design is a subfield of computer engineering and electronics engineering (fabrication) that deals with creating a processor, a key component of computer hardware. The design process involves choosing an instruction set and a certain ...

ers tend to use lower

CPU core voltage The CPU core voltage (''VCORE'') is the power supply voltage supplied to the CPU (which is a digital circuit), GPU, or other device containing a processing core. The amount of power a CPU uses, and thus the amount of heat it dissipates, is the pr ...

s; lower voltages help in reducing

CPU power dissipation Processor power dissipation or processing unit power dissipation is the process in which computer processors consume electrical energy, and dissipate this energy in the form of heat due to the resistance in the electronic circuits. Power manag ...

, which is often specified through

thermal design power The thermal design power (TDP), sometimes called thermal design point, is the maximum amount of heat generated by a computer chip or component (often a CPU, GPU or system on a chip) that the cooling system in a computer is designed to dissipate ...

(TDP) that serves as the

nominal value In economics, nominal value is measured in terms of money, whereas real value is measured against goods or services. A real value is one which has been adjusted for inflation, enabling comparison of quantities as if the prices of goods had not c ...

for designing CPU cooling systems. Some voltage regulators provide a fixed supply voltage to the processor, but most of them sense the required supply voltage from the processor, essentially acting as a continuously-variable adjustable regulator. In particular, VRMs that are soldered to the motherboard are supposed to do the sensing, according to the

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

specification. Modern

video card A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer moni ...

s also use a VRM due to higher power and current requirements. These VRMs may generate a significant amount of heat and require

heat sink A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, th ...

s separate from the GPU.

Voltage identification

The correct supply voltage is communicated by the microprocessor to the VRM at startup via a number of bits called ''VID'' (voltage identification definition). In particular, the VRM initially provides a standard supply voltage to the VID logic, which is the part of the processor whose only aim is to then send the VID to the VRM. When the VRM has received the VID identifying the required supply voltage, it starts acting as a

voltage regulator A voltage regulator is a system designed to automatically maintain a constant voltage. A voltage regulator may use a simple feed-forward design or may include negative feedback. It may use an electromechanical mechanism, or electronic components ...

, providing the required constant voltage supply to the processor. Instead of having a power supply unit generate some fixed voltage, the CPU uses a small set of digital signals, the VID lines, to instruct an on-board power converter of the desired voltage level. The switch-mode

then adjusts its output accordingly. The flexibility so obtained makes it possible to use the same power supply unit for CPUs with different nominal supply voltages and to reduce

power consumption Electric energy consumption is the form of energy consumption that uses electrical energy. Electric energy consumption is the actual energy demand made on existing electricity supply for transportation, residential, industrial, commercial, and ot ...

during idle periods by lowering the supply voltage. For example, a unit with 5-bit VID would output one of at most 32 (2⁵) distinct output voltages. These voltages are usually (but not always) evenly spaced within a given range. Some of the

code word In communication, a code word is an element of a standardized code or protocol. Each code word is assembled in accordance with the specific rules of the code and assigned a unique meaning. Code words are typically used for reasons of reliability, ...

s may be reserved for special functions such as shutting down the unit, hence a 5-bit VID unit may have fewer than 32 output voltage levels. How the numerical codes map to supply voltages is typically specified in tables provided by component manufacturers. Since 2008 VID comes in 5-, 6- and 8-bit varieties and is mostly applied to power modules outputting between and .

VRM and overclocking

The VRMs are essential for

overclocking In computing, overclocking is the practice of increasing the clock rate of a computer to exceed that certified by the manufacturer. Commonly, operating voltage is also increased to maintain a component's operational stability at accelerated spe ...

. The quality of a VRM directly impacts the motherboard’s overclocking potential. The same overclocked processor can exhibit noticeable performance differences when paired with different VRMs. The reason for this is that a steady power supply is needed for successful overclocking. When a chip is pushed past its factory settings, that increases the power draw, so the VRM needs to match its output accordingly.

References

External links

{{commonscat, Voltage regulator modules
"Microprocessor Power Management"

Module Module, modular and modularity may refer to the concept of modularity. They may also refer to: Computing and engineering * Modular design, the engineering discipline of designing complex devices using separately designed sub-components * Mo ...

Digital electronics MOSFETs

Overview

Voltage identification

VRM and overclocking

See also

References

External links