FRU Visual Identification Without Host Power Using Supercapacitors
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Solution Overview
Problem
In server and storage systems, identifying a failed field replaceable unit (FRU) is challenging when host power is disconnected, as existing LED indicators require host power to function, leading to loss of FRU status information and ambiguity in replacement.
Innovation Solution
A device with a storage circuit, power multiplexer/isolation circuit, and alternate power source, such as supercapacitors, is used to store and retain FRU status information and illuminate indicators, even when disconnected from the host power source, utilizing a pushbutton switch to activate the alternate power source for FRU identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If host power is used to illuminate FRU indicators, then FRU status can be displayed during system operation, but FRU status information is lost when the FRU is removed from the host system
Solution Approach 1:
The power supply system is segmented into two independent power sources: the host system power source and a self-contained alternate power source integrated with the FRU. This segmentation allows the FRU to maintain its status indication capability independently when removed from the host system, resolving the information loss problem without significantly increasing overall system complexity.
Solution Approach 2:
The alternate power source is pre-charged while the FRU is installed in the host system. This preliminary charging action ensures that when the FRU is removed, the stored energy is already available to immediately power the status indicators, eliminating the need for complex real-time power management during the transition.
2Ease of operation
If FRU is removed from host system for physical access, then repair technician can access the FRU, but power connection is lost and LED indicators cannot be illuminated
Solution Approach 1:
The alternate power source acts as an intermediary between the FRU and the status indicators. It provides the necessary electrical energy to illuminate the LED indicators when the host power connection is absent, enabling the indicators to function as a mediator that communicates FRU status even during physical removal and replacement operations.
3Reliability
If alternate power source is continuously powered, then FRU status can always be indicated, but energy storage in the alternate power source is depleted
Solution Approach 1:
The system employs periodic action by charging the alternate power source during periods when the FRU is installed and connected to host power, and discharging it only when needed during FRU removal. This periodic charge-discharge cycle maintains reliable status indication while minimizing energy depletion, as the power source is replenished during normal operation and used only during the brief period when the FRU is physically accessed.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables effective visual identification of failed FRUs without host power, minimizing downtime and ensuring accurate replacement by maintaining FRU status information and providing illumination for repair technicians.
Implementation Method 1
an alternate power source, such as supercapacitors
Implementation Method 2
an alternate power source, such as supercapacitors having a capacitance in the range of 1-10 Farads
Implementation Method 3
a power multiplexer/isolation circuit coupled to the storage circuit and a power source for supplying power to the storage circuit during runtime
Implementation Method 4
light emitting diodes (LEDs) are typically used as FRU indications
Data Source
AI summary
The present disclosure is directed to visual field replacement unit (FRU) identification and retaining FRU status information of one or more field replaceable units in a host system device when one or more of the field replaceable units is removed from the host system device disconnecting host power to the removed field replaceable unit(s). The one or more field replaceable units may be located on a carrier printed circuit board assembly and the host system device may contain multiple field replaceable units and/or multiple carrier printed circuit board subassemblies. Once the host power is disconnected from the carrier, an alternate power source continues to provide power to keep the FRU indicator illuminated for repairs or replacement. The FRU indicator is illuminated long enough for a service technician to place the carrier on a bench or table top and recognize the failed FRU from the remaining FRUs.