All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > The Projects Forum


The Projects Forum Working on an electronics project and would like some suggestions, help or critiques? If you would like to comment or assist others with their projects, this is the place to do it.

Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 04-15-2010, 04:43 PM
RSmith RSmith is offline
New Member
Join Date: Apr 2010
Posts: 3
Default Signal Inverter

I need some assistance, please, anyone, I'm a novice so I hope I can communicate what I need sufficiently for you to understand. I'm interfacing an off the shelf board that puts out a PWM (Dalf board from Robot Power) signal that I'm attaching to a Powerex hybrid IGBT driver. The Dalf board's PWM signal is 5VDC CMOS and the input on the IGBT driver is TTL. The documentation from Powerex says the PWM signal has to be inverted before it goes to the driver because the IGBT module is active when the PWM signal the driver gets is "low". The Powerex documentation also suggests using a CD74HC04E CMOS hex inverter. The hex inverter comes in a 14 pin DIP package and on a breadboard mockup with an led it works as expected as long as the input signal never floats. I don't know what kind of liberties I can take in mixing TTL and CMOS. I have not wired up the Dalf board, hex inverter and IGBT driver yet, only the hex inverter on breadboard with an led and 5VDC power supply. I would like to get a single channel inverter so I don't have to be concerned with what to do with the unused inputs and outputs. I have contacted Digikey and Mouser both and they say all they have in a single channel inverter is in a smaller package, so small I can't easily handle it. I also ran across logic to logic optocoupler buffers and inverters in a package that can be handled and used on breadboard and also gives an additional degree of isolation. The optocouplers I've looked (Fairchild 740L6001) at come in TTL and Cmos outputs (there may be others) but only LSTTL input, here again I don't know what liberties I can take in mixing. I also don't really have a good grasp on what additional components I should be adding to this interface circuit in the way of pull up/down resistors and/or filter capacitors before and/or after the inverter be it the CD74HC04E, 740L6001 or something similar. Sorry for the long windiness. Thanks in advance, Rod S.
Reply With Quote


Related Site Pages
Section Title
Worksheet Timer circuits
Worksheet Latch circuits
Worksheet CMOS logic gates
Worksheet TTL logic gates
Video Lecture Basic Amplifier Configuration (Part 1) - Op Amps and Op Amp Circuits
Textbook Basic gate function : Digital Integrated Circuits
Textbook Minterm vs maxterm solution : Karnaugh Mapping
Textbook Logic signal voltage levels : Logic Gates
Textbook Gate universality : Logic Gates
Textbook CMOS gate circuitry : Logic Gates

Similar Threads
Thread Thread Starter Forum Replies Last Post
Why dB or dBm vs Volt/Volt? PRS Radio and Communications 13 01-28-2010 06:25 PM
Design signal in Matlab ethan007 Programmer's Corner 2 05-12-2009 02:50 PM
DTMF signal through an electricity 220V 50Hz kirill2008 The Projects Forum 11 09-24-2008 02:51 AM
MATLAB - Digital Signal Processing lamerooze Programmer's Corner 0 03-13-2008 06:08 PM
5V and -5V signal menewbie Homework Help 9 03-15-2006 09:59 AM

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 09:26 AM.

User-posted content, unless source quoted, is licensed under a Creative Commons Public Domain License.
Powered by vBulletin
Copyright ©2000 - 2014, vBulletin Solutions, Inc.