Patent Application
20060176667
The present invention relates to a device for controlling fan speed, and more particularly to a device for controlling fan speed capable of switching the fan to a fixed rotation speed mode or a changeable rotation speed mode, wherein a user can force the fan to be in the fixed rotation speed mode and the rotation speed of the changeable rotation speed mode automatically depends on a reference signal of the heat source.
According to the development of precision technology, the volume of an electronic device is gradually decreased, but the performance of the electronic device is requested to gradually increase. Thus, the heat dissipating problem of the electronic device is gradually serious. However, current improvement methods mainly utilize an air cooling type heat dissipating fan to guide air and then cool the electronic device. Moreover, the heat generated from the electronic device depends on various parameters of the work time and operation power, and thus a device of controlling fan speed disclosed in most reference patent documents or products receives a reference signal transmitted from the electronic device. The device of controlling fan speed changes the rotation speed of the heat dissipating fan in accordance with the reference signal, whereby different dissipating performance of the heat dissipating fan depends on different heat generated from the electronic device.
The rotation speed of the heat dissipating fan disclosed in current reference patent documents or products is passively controlled after the heat is generated from the electronic device. However, gradually this method for controlling the heat dissipating fan cannot meet the requirement of the electronic device in the future. For example, the electronic device is a power supply. When an external power source provides the electronic device with electric power and transforms the electric power to a load, the electronic device will provide the load with more power so as to increase the temperature of a heat source of the electronic device if the electric potential of the load is increased (e.g. the quantity of the load is increased). After the temperature is high, the rotation speed of the heat dissipating fan is increased for dissipating the heat. According to the electronic device, various electronic components of the electronic device all are heated and then cooled, and thus they are still expanded when hot and to shrunk when cold or they have high thermal impedance, whereby the performance and lifetime of the electronic device are decreased. In addition, various electronic devices disposed in a computer all generate the heat and the interior of the computer is similar to a closed space, thus the heat is quickly accumulated. When a user cannot force the heat dissipating fan to quickly dissipate the heat, possibly the user won't be able to start up the computer because the environmental temperature of the electronic device is too high so as to result in a fault command.
It is an object of the present invention to solve the above-mentioned disadvantages. The present invention provides a device for controlling fan speed to switch the fan to a fixed rotation speed mode or a changeable rotation speed mode in accordance with the operating environment or the requirement of the heat source, wherein the user can force the fan to be in the fixed rotation speed mode and the rotation speed of the changeable rotation speed mode automatically depends on the reference signal of the heat source. The device for controlling fan speed according to the present invention includes a rotation speed controlling unit and a switching unit, wherein according to a reference signal of the heat source the rotation speed controlling unit controls the fan in a changeable rotation speed mode, the switching unit switches the fan to the changeable rotation speed mode or a fixed rotation speed mode, and according to the fixed rotation speed mode the power supply directly provides the driving power to keep the rotation speed of the fan, whereby the user forces the fan to increase the rotation speed and then acquire a best performance of heat dissipating in accordance with the operating environment or the requirement of the heat source.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.
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Although the invention has been explained in relation to its preferred embodiment, it is not used to restrain the invention. It is to be understood that many other possible modifications and variations can be made by those skilled in the art without departing from the spirit and scope of the invention as hereinafter claimed.
