Gigabyte H55N-USB3 Motherboard

Voltage Regulator

The H55N-USB3 comes with a very good seven-phase voltage regulator circuit for the CPU. Four of them are used for CPU main voltage (Vcc, a.k.a. Vcore), two of them are used for the VTT rail, which feeds the CPU integrated memory controller and L3 memory cache, and the last one is used for the integrated video controlled (VAXG). Therefore, this motherboard has a "4+2+1" configuratio
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The MOSFET transistors used in the CPU main power voltage regulator circuit are the NTMFS4921N and NTMFS4935N ("high side" and "low side"), using the ISL6612 and ISL6622 as drivers. They are low RDS(on) MOSFETs, which means this circuit has higher efficiency than regular MOSFETs.

The CPU memory controller (VTT) and the and the memory modules (VDIMM) phases also uses low-RDS(on) MOSFET transistors.

Figure 8: Voltage regulator circuit

All electrolytic capacitors used on this motherboard are solid, and the board uses only ferrite-core coils, which present less energy loss than iron-core coils (i.e., they improve efficiency).

If you want to learn more about the voltage regulator circuit, please read our tutorial on the subject.

Continuing Gigabyte’s tradition, the H55N-USB3 uses thicker copper tracks on the printed circuit board VCC and GND tracks. Usually the printed circuit board power tracks are 35 µm thick, but on this motherboard the power tracks are 70 µm thick. This feature is also called “2 oz. copper tracks” by the manufacturer.

A series of three LEDs show which phases are currently active.

Figure 9: Active phases LEDs