Voltage Regulator
Contents
The CPU voltage regulator circuit of the MSI X79A-GD65 (8D) has ten phases for the CPU main voltage (Vcc a.k.a. Vcore), two for the CPU VSA voltage (memory controller), and two for the CPU VTT voltage (PCI Express and DMI interfaces). Therefore, it uses a “10+2+2” configuration.
Figure 10: Voltage regulator circuit
This motherboard uses military-class components. Electronic components are available in two series, civilian and military. Military components are more expensive but have tighter tolerance and can withstand a wider range of temperatures. All electrolytic capacitors used in the main voltage regulator circuit are SMD (surface mount device), also known as highly-conductive polymerized or simply Hi-c, but the other voltage regulators (memory, chipset, etc.) use solid capacitors. All coils on this motherboard are solid ferrite-core models, also known as SFC, Super Ferrite Choke, which, according to MSI, can provide up to 20% improvement in efficiency.
Each main phase is controlled by a Renesas R2J20655 integrated circuit, which combines the three required transistors (“high side,” “low side,” and “driver”) in a single chip. It also allows the switching clock to be at 1 MHz, which allows efficiency to be over 90 percent. (Usually, voltage regulator circuits switch at 250 kHz.)
The memory voltage regulator has four phases and uses ferrite coils, solid capacitors, and Renesas R2J20655 chips. This is important, because some motherboard manufacturers build high-end voltage regulators for the CPU but use lower-quality parts on the other voltage regulators.
If you want to learn more about the voltage regulator circuit, please read our tutorial on the subject.
The motherboard has a series of 12 LEDs on its edge near the voltage regulator circuit for you to monitor the phases of the Vcc and VSA (memory controller) voltages, and four LEDs for you to monitor the phases of the memory voltage regulator.
Figure 11: CPU phase-monitoring LEDs
Figure 12: Memory phase-monitoring LEDs
Figure 13: Memory phase-monitoring LEDs
