Gigabyte Z68X-UD3H-B3 Motherboard

Voltage Regulator

The CPU voltage regulator circuit of the Gigabyte Z68X-UD3H-B3 has four phases for the CPU main voltage (Vcc a.k.a. Vcore), two for the CPU VTT voltage (integrated memory controller and L3 memory cache), and one for the CPU VAXG voltage (integrated video controller). Therefore, it uses a “4+2+1” configuration.

Figure 8: Voltage regulator circuit

Figure 9: Voltage regulator circuit

This motherboard uses solid ferrite-core coils, which present less energy loss than iron-core coils (i.e., they improve efficiency) and solid capacitors. Each main phase is controlled by an SiC769CD 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%. (Usually, voltage regulator circuits switch at 250 kHz.)

Strangely, Gigabyte added a passive heatsink only over the Vcc and VAXG integrated circuits, leaving the VTT integrated circuits without a heatsink.

There are two phases for the chipset voltage and two phases for the memory voltage, also using ferrite coils, solid capacitors, and low-RDS(on) transistors (i.e., high-efficiency transistors). This is important because some motherboards 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.