Browse Prior Art Database

Sensing Voltage to Detect Device Presents

IP.com Disclosure Number: IPCOM000125913D
Original Publication Date: 2005-Jun-22
Included in the Prior Art Database: 2005-Jun-22
Document File: 3 page(s) / 36K

Publishing Venue

IBM

Abstract

Detection of devices can be done in many ways. This method illustrates the novel use of existing structures to enable the detection of a device plugged in a modular interface.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 55% of the total text.

Page 1 of 3

Sensing Voltage to Detect Device Presents

There are many ways to detect devices in a modular environment. While some methods may use a dedicated pin to detect presence of a device, it has disadvantages: increased cable and connector size, increased airflow restriction and increased cable and connector cost.

The blades front panel will always have the power LED on the front panel either blinking or on solid. The series resistor for the front LED is on the blades planar. Our BMC can measure the voltage at this series resistor to determine if the cable is connected. This will eliminate the need to dedicate a pin just for cable detection. Adding a pulldown resistor near series resistor and measuring voltage at that node by BMC will help detect whether cable is present or not.

Sense the voltage drop across the LEDs current limiting resistor. The BMC controls the power LED and will know when it is on or off, but the cable disconnect is not detected by BMC. Adding a pulldown resistor near series resistor and measuring voltage at that node by BMC will help detect whether cable is present or not.

Figure 1 shows a current circuit diagram which provide power to LED connector but does not detect cable present.

Figure 2 provides capabilities to detect cable present without adding any connector pin to connector. The new circuit needs to add pulldown resistor and connection to BMC.

1

[This page contains 1 picture or other non-text object]

Page 2 of 3

There are four different po...