Zotac H67-ITX WiFi Motherboard

Voltage Regulator

The CPU voltage regulator circuit of the H67-ITX WiFi has four phases for the CPU main voltage (Vcc a.k.a. Vcore), one 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+1+1” configuration.

Figure 9: Voltage regulator circuit

Figure 10: Voltage regulator circuit

Figure 11: 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 temperature. The main voltage regulator circuit uses a mix of solid and SMD (surface mount device) capacitors, also known as highly-conductive polymerized or simply Hi-c. All coils on this motherboard are solid ferrite-core models, which provide less energy loss, improving efficiency up to 20%.

Each main phase is controlled by a Renesas R2J20651NP integrated circuit (click here for a detailed description and here for its datasheet), 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.)

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