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Method of Varying Turn-On voltage by Leveraging Slot ID

IP.com Disclosure Number: IPCOM000247319D
Publication Date: 2016-Aug-22
Document File: 3 page(s) / 129K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method to use existing canister slot identifiers to stagger the turn on voltage of the canister switches and prevent large current inrushes to a device.

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Method of Varying Turn-On voltage by Leveraging Slot ID

A high availability electronic system often has multiple hot pluggable canisters. Each hot pluggable canister needs a series switch element on the power rail to the canister to isolate the capacitance of the canister from the main power of the system. When a canister is hot plugged, the switch slowly turns on, to prevent a large current inrush to the canister. Large current inrushes to a device can cause the main power supply to shut off; this is not desirable.

In another case, all canisters are already plugged into the system when the system is powered-on. In this case, it is desirable to let the main power supply come up to a known good minimum operating voltage before powering on the canisters. To do this, circuitry associated with the switch device monitors the input voltage to the canister. When the minimum operating voltage is met, it will turn on the switch, thus powering the canister.

The problem with this is that, in a system with a large number of identical canisters, all the canisters will simultaneously turn on after the main supply has ramped-up some amount. This causes that same undesired current spike of charging all the canister capacitors at once. The main power supply may turn off due to an over current, causing the system to lose power.

The core idea of this solution is to use existing canister slot identifiers to stagger the turn on voltage of the switches. When a large number of identical canisters are present, those canisters may have some connector pins on the backplane that tell the identical canisters which slot they are plugged into. Each canister slot has a unique ID. By tying this unique canister information into the switch logic, the switch logic can vary the turn- on voltage of the switch based on the slot ID. Thus, not all of the identical canisters turn o...