voltage regulator module (VRM)
A Voltage Regulator Module (VRM) is functionally a PoL converter that generates the supply voltage for microprocessors from the supply voltages for the motherboard.
Such a DC/DC converter converts the supply voltage from the power supply unit from 3.3 V, 5 V or 12 V to the lower supply voltages for central processing units, graphics processors, microprocessors, ULV process ors and CULV processors. The latter chips operate with supply voltages below 1.5 V, whereas the Pentium had a supply voltage of 2.8 V. Unlike a PoL converter, a Voltage Regulator Module is not located in the immediate vicinity of the power chips. The connections from the VRM module to the pads of the chips are made via the Power Distribution Network( PDN).
Voltage Regulator Modules can be installed as stand-alone chips or as a small PCB on the motherboard, but they can also be an integrated part of the chip, as an Integrated Voltage Regulator( IVR) or as a Fully Integrated Regulator (FIVR).