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(RSS) Method to detect CPU heatsink attachment Disclosure Number: IPCOM000030633D
Original Publication Date: 2004-Aug-20
Included in the Prior Art Database: 2004-Aug-20
Document File: 1 page(s) / 30K

Publishing Venue



CPUs used in personal computers use large amounts of power and require a CPU cooler, usually in the form of a heatsink and fan. System designers usually incorporate fan fail detectors to shut off the processor or somehow limit the power dissipated by the CPU. The attached heatsink usually provides enough thermal mass to slow the heat-up of the CPU to allow the over-temperature condition to be detected by BIOS and the ACPI-compliant operating system. If the heatsink is not attached to the CPU, it will overheat quickly and in some situations damage the CPU. A typical reason the heatsink is not attached is because the metal clip which holds the heatsink to the CPU is not present or not properly installed. The invention is an inexpensive method to detect if the heatsink clip is in place.

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(RSS) Method to detect CPU heatsink attachment

     In a common heat sink clamp a clip is provided on either side of the heat sink on which the spring loaded hold down bar is attached. In Option 1, the clips on either side are separated into two separate hooks. The first hook (1) is attached to board ground while the second hook (2) is pulled to a reference voltage and monitored by a logic gate. When the hold down bar is attached a circuit is completed between the hooks (1,2) causing the gate to see a low or logic '0'. This is repeated for the hooks on the other side of the heat sink (7,8). Option 2 uses single hooks on either side of the heat sink. The hook on one side is connected to ground while the hook on the other side is pulled up to a reference voltage and connected to the monitoring logic. Installation of the hold down bard completes the circuit and pulls the Heat_sink_good signal low or to a logic '0'.

1 2

Heat sink installation detection system 26 Feb, 2003

1. Heat sink board clip 1, T1
2. Heat sink board clip 2, T2
3. Heat sink hold down bar
4. Heat sink
5. Zero Insertion force socket
6. Microchip
7. Heat sink board clip 3, T3
8. Heat sink board clip 4, T4
9. Printed Circuit Board

3 4





T1 T2

T3 T3


Option 1

7 8

1 2


T1 T2

T3 T3


Option 2


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