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Innovative method to implement 240VA protection without mechanical barriers Disclosure Number: IPCOM000030640D
Original Publication Date: 2004-Aug-20
Included in the Prior Art Database: 2004-Aug-20
Document File: 1 page(s) / 22K

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In computers today, the output of the power supply is converted to the voltages required through out the system (12V, 5V, 3.3V, 2.5V, etc.). The voltages are divided into 240VA boundaries for safety requirements. In the past, where the voltage is divided into those boundaries, mechanical barriers have been put in place to protect the end user from the high voltages and from accidentally electrocuting themselves.

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Innovative method to implement 240VA protection without mechanical barriers

     The Relentless server was designed with a memory card above the power backplane where the voltage conversion takes place. This memory card inhibits the end user from accessing the high voltage area of the power backplane and prevents the user from electrocution. If the memory card is not populated a fail safe method prevents the server from powering up (providing power to the electronics).

     If the memory card in Relentless was not populated, there would be no barrier over the power backplane protecting the user from the high voltages on the power backplane. The power backplane has a sense circuit that detects the presence of the memory card and if the memory card is not present the power supplies are not allowed to turn on.

     A pin on the memory card connector is tied directly to ground. This signal (PS_SAFTEY_SHUTDOWN) is then routed through the CPU card to the Power Backplane. Circuits on the Power Backplane will not allow the power supplies to turn on if this signal (PS_SAFTEY_SHUTDOWN) is active HIGH (5V continuous) (i.e. the memory card is not populated). If the memory card was populated, this signal (PS_SAFTEY_SHUTDOWN) would be tied to GND and the power supplies allowed to turn on. The power supplies are turned on when the PSx_DC_ON# signal is active LOW.