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Using a Light Sensing Circuit to Enforce Electrical Safety Limits

IP.com Disclosure Number: IPCOM000237308D
Publication Date: 2014-Jun-12
Document File: 2 page(s) / 35K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to use a light sensing circuit to provide 240VA protection to servers in place of a typical pressure switch in the server cover. This light sensor detects when the top cover is opened or removed and then, through logic on the server planar, enforces the 240VA safety limits.

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Using a Light Sensing Circuit to Enforce Electrical Safety Limits

User accessible areas of servers, per safety standards, are required to provide 240VA protection to limit the amount of energy to which a person is exposed in the event of an accidental short circuit. This protection can be either electrical or mechanical in nature. Many servers provide mechanical protection via use of a pressure switch in the top cover of the server to detect when parts of a server are exposed to the user. When the system detects the opening/removal of the top cover, the server enforces the 240VA safety limits, either by adjusting over current thresholds of the exposed areas or by powering down the system.

There are two drawbacks to this solution. One is that this pressure switch can easily be forced into the on position by the user, thus defeating the 240VA protection. The other drawback is the reliability of the switch connection itself. If the top cover is not fully closed or if the switch wears out, then the server can experience unwanted power-down events. A more robust solution is needed to effectively provide 240VA protection when a server's top cover is removed.

The novel solution is to use a light sensing circuit to provide 240VA protection to servers in place of a typical pressure switch in the server cover. A light sensor can detect when the top cover has been opened or removed and through logic on the server planar enforce the 240VA safety limits. Using a light sensin...