• Join
  • Sign In with my.TI Login
Texas Instruments
  • Products
  • Applications
  • Tools & Software
  • Support & Community
  • Sample & Buy
  • About TI
Sample & Purchase Cart Sample & Purchase Cart
  • Search
  • Advanced
TI E2E™ Community
  • Support Forums
  • Blogs
  • Groups
  • Videos
  • 简体中文
  • More ...
TI Home » TI E2E Community » Support Forums » Amplifiers » Audio Amplifiers » Audio Amplifiers Forum » Question about BTL for TPA3123D2
Share
Audio Amplifiers
  • Forum
  • E2E Wiki
Options
  • Subscribe via RSS
Check out
Analog Wire blog
  • $core_v2_blog.Current.Name

    RS-485 - Who says you can't teach an old dog new tricks?

    Posted 2 days ago
    by Neel Seshan
    Would you agree that RS-485 has turned out to be one of the most...
  • $core_v2_blog.Current.Name

    Filter for thought

    Posted 3 days ago
    by Soufiane Bendaoud
    Have you ever wondered how engineers designed active filters...
  • $core_v2_blog.Current.Name

    Let’s take this driver out for a spin

    Posted 9 days ago
    by Soufiane Bendaoud
    Before I suggest a suitable op amp to drive an ADC, I look at...

Question about BTL for TPA3123D2

Question about BTL for TPA3123D2

This question is answered
Justin Reyes
Posted by Justin Reyes
on Jul 31 2009 10:16 AM
Prodigy20 points

Hello!

I have a question regarding the audio input in the TPA3123D2 Class-D Audio Power Amplifier for anyone that has experience with this chip. I currently have the speaker output filters in a Bridge-Tied Load (BTL) configuration using one speaker. What happens if I tie both the left and right audio input pins (LIN and RIN) together, so that they are receiving the same audio signal? Will I hear an amplified signal from the speaker or just no sound at all?

Thanks for your help!

TPA3123D2
Report Abuse
  • Reply
You have posted to a forum that requires a moderator to approve posts before they are publicly available.
All Replies
  • Fred Shipley
    Posted by Fred Shipley
    on Jul 31 2009 23:37 PM
    Verified Answer
    Verified by Don Dapkus
    Genius16650 points

    Hello Justin:

    Since the TPA3123D2 would behave as a  differential input amplifier in BTL mode, if you connect LIN and RIN the output would be the input signal multiplied by the Common Mode Rejection Ratio (CMRR) and this residual multiplied by the gain of the amplifier.  Since this is not a true differential amplifier, you could consider the gain matching to be your CMRR or your residual signal would be ~60dB less than the input signal.

    The residual signal would be multiplied by the gain of the amplifier, 20dB to 32dB; therefore, the output signal would be 28dB to 40dB below the input signal.

    This is all a long way of saying the there would not be very little output signal.

    Regards,

    Fred

    Report Abuse
    • Reply
    You have posted to a forum that requires a moderator to approve posts before they are publicly available.
  • Justin Reyes
    Posted by Justin Reyes
    on Aug 03 2009 10:31 AM
    Prodigy20 points

    thanks for the explanation and for your help Fred!

    Report Abuse
    • Reply
    You have posted to a forum that requires a moderator to approve posts before they are publicly available.
TI E2E™ Community
  • Support Forums
  • Blogs
  • Videos
  • Groups
  • Site Support & Feedback
  • Settings
TI E2E™ Community Groups
  • TI University Program
  • Make the Switch
  • Microcontroller Projects
  • Motor Drive & Control
Other Communities
  • Deyisupport
  • Designsomething.org
  • beagleboard.org
  • TI on Element 14
  • TI on TechXchangeSM
Other Technical & Support Resources
  • WEBENCH® Design Center
  • Product Information Centers
  • Technical Documents
  • TI Design Network
  • TI Technical Articles
  • TI Training

All content and materials on this site are provided "as is". TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with regard to these materials, including but not limited to all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement of any third party intellectual property right. TI and its respective suppliers and providers of content make no representations about the suitability of these materials for any purpose and disclaim all warranties and conditions with respect to these materials. No license, either express or implied, by estoppel or otherwise, is granted by TI. Use of the information on this site may require a license from a third party, or a license from TI.

Content on this site may contain or be subject to specific guidelines or limitations on use. All postings and use of the content on this site are subject to the Terms of Use of the site; third parties using this content agree to abide by any limitations or guidelines and to comply with the Terms of Use of this site. TI, its suppliers and providers of content reserve the right to make corrections, deletions, modifications, enhancements, improvements and other changes to the content and materials, its products, programs and services at any time or to move or discontinue any content, products, programs, or services without notice.

Follow Us Texas Instruments on Facebook Texas Instruments on Twitter Texas Instruments on LinkedIn Texas Instruments on Google+
TI Worldwide | Contact Us | my.TI Login | Site Map | Corporate Citizenship | mobile m.ti.com (Mobile Version)

TI is a global semiconductor design and manufacturing company. Innovate with 100,000+ analog ICs and
embedded processors, along with software, tools and the industry’s largest sales/support staff.

© Copyright 1995-2013 Texas Instruments Incorporated. All rights reserved.
Trademarks | Privacy Policy | Terms of Use