Browse Prior Art Database

Regulator for CMOS Substrate Voltage Generator

IP.com Disclosure Number: IPCOM000060488D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Dillinger, T: AUTHOR

Abstract

Variations in the negative output voltage of a CMOS technology substrate voltage generator due to supply voltage and leakage current variations are reduced by the addition of a regulator circuit which modulates the magnitude of the generator's charge pump current to control the output voltage. The figure illustrates the regulator circuit for addition to a CMOS technology substrate generator. A P-channel device is used as the sensing device, connected as a voltage follower to a subsequent logic gate. This voltage follower configuration adds a P-channel threshold voltage to the divided substrate voltage; the sum of the voltage divider output and VT,p is positive and is used as a logic input signal to the driven gate.

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 54% of the total text.

Page 1 of 2

Regulator for CMOS Substrate Voltage Generator

Variations in the negative output voltage of a CMOS technology substrate voltage generator due to supply voltage and leakage current variations are reduced by the addition of a regulator circuit which modulates the magnitude of the generator's charge pump current to control the output voltage. The figure illustrates the regulator circuit for addition to a CMOS technology substrate generator. A P-channel device is used as the sensing device, connected as a voltage follower to a subsequent logic gate. This voltage follower configuration adds a P-channel threshold voltage to the divided substrate voltage; the sum of the voltage divider output and VT,p is positive and is used as a logic input signal to the driven gate. For the circuit to work properly, the magnitude of the P- channel threshold voltage at a source-to-well reverse bias of (VW - VF) must be greater than the N-channel threshold at the desired operating substrate voltage. The voltage divider consists of two N- channel devices connected in their linear (resistive) operating region. The regulator design is relatively insensitive to variations in the supply voltage--neither the divider nor the high gain logic gate is particularly sensitive to the supply voltage. The voltage follower value (VT,p) is slightly sensitive to VDD = VW as it affects the source-to-well voltage, but only to a small percentage. As the temperature increases, VT,n decreases, lowering the sw...