Browse Prior Art Database

Power Supply Sequencing Circuit

IP.com Disclosure Number: IPCOM000086721D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

King, KR: AUTHOR

Abstract

A power-supply sequencing circuit is located on each chip and functions to monitor and alter supply voltages to protect linear load field-effect transistor (FET) chips against destruction due to improper power-supply sequencing or the loss of voltage.

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 100% of the total text.

Page 1 of 2

Power Supply Sequencing Circuit

A power-supply sequencing circuit is located on each chip and functions to monitor and alter supply voltages to protect linear load field-effect transistor (FET) chips against destruction due to improper power-supply sequencing or the loss of voltage.

The circuit monitors the V+ (the load-drain voltage) and V(substrate voltage) and adjusts Vlg* (regulated load-gate voltage), thereby protecting the FET chip from possible destruction.

Possible destruction occurs when both positive supplies (Vand Vlg) are valid before V- thereby effecting higher power dissipation and module destruction. When V+ is turned on first prior to V-, Vs is approximately equal to V+ and even though Vlg is high, Vlg* is held low by device 11 until V- is sequenced on. When Vlg comes on prior to V-, as V+ increases, V- increases thereby reducing Vlg*. Thus, Vlg* is held low until V- is turned on. Resistor 13 is used in the regulating function and capacitor 15 buffers the current spikes on Vlg*. Thus, the addition of the resistor, capacitor and on-chip sequencing circuit eliminates the necessity of power-supply sequencing circuits associated with the supply.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]