Gigabyte Z68X-UD5-B3 Motherboard

Voltage Regulator

The CPU voltage regulator circuit of the Z68X-UD5-B3 has 20 phases for the CPU main voltage (Vcc a.k.a. Vcore) and two for the CPU VTT voltage (integrated memory controller and L3 memory cache). Therefore, it uses a “20+2” configuration.

Figure 7: Voltage regulator circuit

Figure 8: 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.)

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 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 LEDs for you to monitor the phases of the voltage regulator circuit. You can monitor the main phases through five LEDs, each one representing four phases, and the two VTT phases through two separate LEDs.

Figure 9: Phase-monitoring LEDs