Browse Prior Art Database

Single-Pin Substrate Generator

IP.com Disclosure Number: IPCOM000044161D
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Perry, P: AUTHOR

Abstract

The current implementation of the substrate generator 11 (Fig. 1) has its own power supply pin MVDD 12 as well as a pin VSX 13 to supply an external substrate voltage. A single-pin substrate generator allows one module pin to either power up the substrate generator 11 or to force the substrate to an applied negative voltage. A diode 14 (Fig. 2) is placed between the substrate and the power supply pin 12, allowing the same pin 12 to be used to power the substrate generator 11 or provide an external substrate voltage, via pin 13, thus saving one module pin. As the external substrate voltage is applied, the substrate generator 11 is shut off, allowing no current to flow through it. The diode 14 would have some voltage drop, but if properly designed, the drop would be small because the current traveling through it would be small.

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Single-Pin Substrate Generator

The current implementation of the substrate generator 11 (Fig. 1) has its own power supply pin MVDD 12 as well as a pin VSX 13 to supply an external substrate voltage. A single-pin substrate generator allows one module pin to either power up the substrate generator 11 or to force the substrate to an applied negative voltage. A diode 14 (Fig. 2) is placed between the substrate and the power supply pin 12, allowing the same pin 12 to be used to power the substrate generator 11 or provide an external substrate voltage, via pin 13, thus saving one module pin. As the external substrate voltage is applied, the substrate generator 11 is shut off, allowing no current to flow through it. The diode 14 would have some voltage drop, but if properly designed, the drop would be small because the current traveling through it would be small. The substrate should be brought out to a pad on the chip to allow measurement of the substrate generator 11 to be made at wafer level. Indirect measurement of the generator voltage can be made at module level by forward biasing the protect diode of an input and knowing the approximate diode drop.

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