Browse Prior Art Database

Automatic detect logic of buffer power pin

IP.com Disclosure Number: IPCOM000032058D
Original Publication Date: 2004-Oct-21
Included in the Prior Art Database: 2004-Oct-21
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Abstract

Disclosed is a circuit for detecting buffer power pin connection automatically without probing power pin directly. This circuit provides the difference of buffer output voltage between the cases that buffer power is supplied or not. When buffer power is not supplied, it can be detected automatically by checking the difference of buffer output voltage with this disclosed circuit.

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Automatic detect logic of buffer power pin

 Disclosed is a circuit for detecting buffer power pin connection automatically without probing power pin directly. This circuit provides the difference of buffer output voltage between the cases that buffer power is supplied or not.

 As a feature of buffer IC, it can through the input signal to output even if power is not supplied to buffer IC. But in such case, the input signal is not emphasized by buffer IC, and if a device that request large volume of input electric current is connected, buffer IC can't manage to output the requested volume of electric current. Consequently, connected device can't receive high revel input voltage and can't operate correctly.

 If the buffer IC connection is tested just by verifying the output signal voltage with low electric current load, this failure can not be detected because buffer IC can through the input signal to output even if power is not supplied. This failure can be detected only when high electric current load is connected to output signal.

Disclosed circuit is the one that makes the virtual high electric current load and attached Figure1 shows that implementation. By adding resistor parallel to the test probe of buffer output pin like Figure1, this output pin becomes always under high electric current load, and in such case, buffer IC can't supply expected voltage to test probe if its power is not supplied. The difference of the output voltage of buffer IC between these 2 ca...