How AC4G WorksActive Cool's AC4G high-power thermo-electric cooling system for PC processors consists of the Cooling Unit and the Power and Control Unit.
The Power and Control Unit is a PC card containing an AC/DC switching mode power supply and a microprocessor controller. The power supply, which receives AC input directly from the electric network (through a plug in the bracket of the card), provides the power to the thermo-electric unit. The power supply is controlled by the microprocessor.
The microprocessor controller receives input from the ambient temperature sensor and the CPU temperature sensor. The microprocessor samples the temperature more than 40 times per second, and adjusts the cooling power of the thermo-electric unit and the speed of the CPU and case fans accordingly.
To reduce computer noise, the microprocessor normally runs the CPU and case fans at 6 volts (½ power, drastic reduction in noise). When the temperature of the ambient air rises, the microprocessor operates the PC case fans at higher power until temperature is reduced. If the CPU temperature rises, the microprocessor initiates a carefully orchestrated reaction. First, power is increased to the (virtually noiseless) thermo-electric unit. If this is insufficient, then additional power can be supplied both to the thermo-electric unit and to the CPU fan. When the thermal load is reduced, the fans can return to quiet operation. During short bursts of processor load, the fans are often not needed.
Many motherboards issue warning messages if the CPU fan is not operating at full speed; therefore, the AC4G sends a simulated fan pulse to the motherboard. The microprocessor monitors the actual fan speed. If the fan stalls or fails, the microprocessor stops the simulation pulse to the motherboard, so that the user will receive the customary warning of fan failure.
AC4G is powered independently of the PC and does not use PC resources.
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