• State TI Thinks Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 2 answers
  • Subscribers 31 subscribers
  • Views 460 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Audio amplifer for 100V line

Yogesh Singhal
Prodigy 175 points
Other Parts Discussed in Thread: TAS5558

Dear Team

we are looking for a PA amplifier of 100W output.

we want a 100V line system , without output transformer, in class D configuration

Current class AB amplifier has bulky lamination transformer for making it 100V line system

looking for a solution/refernce design

rgds

yogesh singhal

  • 0
    TI__Mastermind 35510 points

    Hi Yogesh

       100W output power is not a problem, but 100V seems too large. Do you mean the output voltage need to reach 100V? May I ask what is the impedance value of their speaker? 

  • 0 in reply to Shadow He
    Prodigy 140 points

    I've seen 70V line PA systems, I suppose 100V isn't much different other than it's "one louder".

    The idea is to reduce I2R losses in long distribution lines by increasing the load impedance.  A transformer is used at each loudspeaker to step the line down to feed a common 8-ohm driver, with taps for various power levels.

    You could look at designs for a sine wave inverter output stage or AC motor drive as a starting point.  What are your audio bandwidth and THD+N design goals?

  • 0 in reply to Jeff Wright1
    TI__Mastermind 35510 points

    Hi Jeff

       Understand your using. However, the amplifier need to output 100V directly to your transformer, it's still too large for audio amplifier. Our products mainly forces on the none-transformer using.

       The target THD is usually <0.03%@1KHz, 1W. Bandwidth up to 175KHz at consumer side products, 

  • 0 in reply to Shadow He
    Prodigy 140 points

    I agree, 100Vrms is a lot to generate directly from any solid-state amplifier, audio or otherwise.  There are designs that aren't specifically intended for audio, but could be made to work.  I was making an out-of-the-box suggestion because sometimes that's what it takes to design something that isn't commonly made.

    They mentioned 100V class-D and I immediately started thinking of high voltage high/low-side gate drivers used in power supply applications.  I have to design a wide variety of circuits, including high-performance audio, so there was some crossover thinking going on there.

    There is a need for this kind of equipment in pro and commercial audio. Here are some related forum posts:

    TPA3116D2: transformerless 100V line PA system

    120W mono class d with 100V output line

    TPA3156D2: Class-D Amplifier Output for a 100V audio transformer

    Hope you have a nice day.

  • 0 in reply to Jeff Wright1
    TI__Mastermind 35510 points

    Hi Jeff

      In that case, maybe there's some way you could have a try.

      The first is to use audio processor + external amplifier or H bridge. You could check device TAS5558, it could help you transfer audio input to PWM output, then you need to find a suitable H bridge for output power. The problem is, output stage is open loop, you may find THD a little hard to control. Special audio power stage would be the best choice, but still not a suitable device could reach 100V.

      The second is if you could add another transformer at output stage of our Class-D amp, would be much easier. Our amp could drive transformer and give you 100V on the line.

      No third option from my thinking, unless you could accept decrease this 100V to around 50V, we do have power stage could reach to this level.

  • 0 in reply to Shadow He
    Prodigy 175 points

    Dear Jeff

    adding a transformer is a cost, Transformer based on EI lamination or based on Toroidal coil is posssible but size is big and expensive.

    can we have a design based on ferrite (like smps transformer) , we need a frequency operation 50Hz to 20KHz .

    some offer transformer less class D amplifier for 70/100V line...what are these?

  • 0 in reply to Yogesh Singhal
    TI__Mastermind 35510 points

    Hi Yogesh

      Maybe you could e-mail to Jeff directly for further discuss. He may not get real time notification from here.