A method of system cooling for hand held device
Original Publication Date: 2000-Dec-01
Included in the Prior Art Database: 2003-Jun-12
This article describes a system cooling method for the handheld devices those have not enough space to implement the cooling fan. Thin and light are the mandatory requirement for the handheld device (ex. tablet type system for the web browsing and mailing etc.) In many case, tablet type PC is not required to operate so high frequency in the standalone mode from application scenario and power consumption point of view. This is important fact for the cooling system design. Usually, high performance CPU needs big cooling mechanism. Typical cooling system is not suitable for thin handheld device. New cooling approach enables a hand held device to have high performance CPU without big cooling mechanism. Attached figure shows the example of new cooling method. The hand held device (1) has minimum cooling mechanism like some holes with a small fin. The Cradle (2) has some holes match the hand held device's holes and enough cooling fan for the hand held device. During attached operation on the cradle, usually AC powered operating mode, the system could be RUN at the maximum CPU frequency, that means user can use some applications those require high performance CPU. At this moment, the cooling system on the cradle will be working for the hand held devise. With the cooling fan that is implemented in the cradle, CPU can work at the maximum frequency. During standalone operation, battery operation mode, CPU dose not work at the maximum frequency. This is also effective for the battery life point of view. The control of CPU frequency is easily implemented by the S/W driver. In the standalone operating mode, light applications are processed such as off line web browsing etc.