Browse Prior Art Database

Multivibrator

IP.com Disclosure Number: IPCOM000080566D
Original Publication Date: 1974-Jan-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

McDonald, CM: AUTHOR

Abstract

This off-chip driver is a noninverting metal-oxide semiconductor field-effect transistor (MOSFET) network, utilized as a buffer stage between a MOSFET Schmitt trigger and an RC network to provide a multivibrator circuit. The hysteresis affect of the Schmitt trigger provides a delay time in switching the output, while the capacitor is either charging or discharging.

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

Multivibrator

This off-chip driver is a noninverting metal-oxide semiconductor field-effect transistor (MOSFET) network, utilized as a buffer stage between a MOSFET Schmitt trigger and an RC network to provide a multivibrator circuit. The hysteresis affect of the Schmitt trigger provides a delay time in switching the output, while the capacitor is either charging or discharging.

FETs 1-4 make up a Schmitt trigger while FETs 5-6 control the hysteresis. Initially, capacitor C charges through R1 and R2 to VCH (see Fig. 2). During this time, FET 2 is off and FETs 1, 4, 5, and 6 are active providing a bias voltage at node 2. FETs 5 and 6 maintain the bias voltage relatively constant with variations of temperature and voltage supplies. Since FET 2 is off, FET 3 provides an up level for the output.

When the capacitor voltage reaches VCH, FET 2 turns on turning off FET 4. FET 1 remains active and turns off FETs 5 and 6. FETs 1 and 2 provide a down level at the output. The output down level is transposed through the off-chip driver (OCD) to node 4, providing a discharge path for the capacitor through R2. When the capacitor voltage reaches VCL, FET 2 will turn off and the cycle repeats.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text objects]