Many electronic devices have inadequate thermal management. They either get too hot for comfort or so hot that component or system reliability is reduced. Many customers of electronic devices are starting to recognize that manufacturers are cutting corners in thermal design as processor speeds keep increasing. FIGS. 1A through 1D represent different prior art approaches using fans by several manufacturers.
FIG. 1A illustrates one prior art approach to cooling a heat producing component 240 in an electronic device such as a notebook computer. An air-moving device 100, such as a fan or blower, blows air across the heat producing component 240 and the air then exits the electronic device. While this approach cools the heat producing component, it ignores the rest of the system components 300 which typically comprise one half to two thirds of the system thermal load.
FIG. 1B illustrates another prior art approach in which the air from air-moving device 100 that cools heat producing component 240 passes over system components 300 before exiting the electronic device. The result of this approach is that the system components 300 are heated by the warm heat producing component 240 air flow and this heating may cause some of the system components 300 to fail prematurely. Additionally, the air that does exit the electronic device is warmer than desired, often to the detriment of the user's comfort.
FIG. 1C illustrates an alternative prior art arrangement where the cool outside air pulled into the electronic device by air-moving device 100 passes over system components 300 before this air passes across heat producing component 240. While system components 300 are kept cooler, the efficiency on cooling heat producing component 240 decreases because the air reaching it is warmed by system components 300. Again, the air exiting the electronic device is warmer than desired causing user discomfort.
FIG. 1D illustrates a prior art approach to creating two separate air flows for the electronic device 240 and system components 300 by using two fans 100, one for each heat source and separated by wall 232. This approach is difficult to implement in smaller electronic devices because it is more expensive, it has higher power consumption and it needs more space for each fan.
Therefore, while fans or blowers have been used in may different configurations as cooling solutions in electronic devices, such as notebook computers, a need exists when using a single fan or blower to separate cooling flows of outside air for the CPU and the rest of the system.