Intel TFX12V manual Airflow / Fan, AC Connector

TFX12V Power Supply Design Guide

Thin Form Factor with 12-V Connector

Version 2.0

3.5 Airflow / Fan

The designer’s choice of a power supply cooling solution depends in part on the targeted end-use system application(s). At a minimum, the power supply design must ensure its own reliable and safe operation.

Fan location/direction: In general, exhausting air from the system chassis enclosure via a power supply fan is the preferred, most common, and most widely applicable system-level airflow solution. The location of the fan can have a large effect on how efficiently this air is exhausted. The location of the fan shown in Figure 9 allows the fan to be located close to the processor cooling solution when used in the common fan left configuration shown in Figure 11. This close proximity of the fan will aid in the evacuation of heated air and helps keep the total system cooler.

Fan size/speed: The TFX12V power supply has an 80 mm axial fan as shown in Figure 9. It is recommended that a thermally sensitive fan speed control circuit be used to balance system-level thermal and acoustic performance. The circuit typically senses the temperature of the secondary heat sink and/or incoming ambient air and adjusts the fan speed as necessary to keep power supply and system component temperatures within specifications. Both the power supply and system designers should be aware of the dependencies of the power supply and system temperatures on the control circuit response curve and fan size and should specify them carefully.

The power supply fan should be turned off when PS_ON# is de-asserted (high). In this state, any remaining active power supply circuitry must rely only on passive convection for cooling.

Venting: In general, more venting in a power supply case yields reduced airflow impedance and improved cooling performance. Intake and exhaust vents should be as large, open, and unobstructed as possible so as not to impede airflow or generate excessive acoustic noise. In particular, avoid placing objects within 0.5 inches of the intake or exhaust of the fan itself. A raised wire fan grill is recommended instead of a stamped metal vent for improved airflow and reduced acoustic noise for the intake vent. Figure 9 shows the suggested TFX12V exhaust vent pattern.

Considerations to the previous venting guidelines are:

•Openings must be sufficiently designed to meet the safety requirements described in Section 5.

•Larger openings yield decreased EMI-shielding performance. The suggested pattern in Figure 9 sufficiently shields EMI in most power supplies, but the design should always be tested as outlined in Section 6.1.

NOTE:

Venting in inappropriate locations can detrimentally allow airflow to bypass those areas where it is needed.

3.6 AC Connector

The AC input receptacle should be an IEC 320 type or equivalent. In lieu of a dedicated switch, the IEC 320 receptacle may be considered the mains disconnect.