TL494 audio simple way

Discussion in 'General Electronics Chat' started by Motanache, May 16, 2017.

  1. Motanache

    Thread Starter Member

    Mar 2, 2015
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    http://geekcircuits.com/2010/07/class-d-amp-using-tl494-dc-to-dc-converter-chip-2/
    TL494 Audio amplifier

    I made this scheme and worked very well:
    [​IMG]

    I do not have the MOS driver IC from the following schema:
    [​IMG]

    I do not have the IR2010 or any closer.
    What to use?
    I can use transistors MOSFET (N-MOS, IRF840) or bipolar.

    Create the driver from discrete components?
    Or try transformer for Gate drive?
    Anyway, I need dead time what is done by group D6 / R6 and D7/R7, D4/R3, D5/R4.
    For D6 and D7 I have neither the equivalent.
    I have 1n4007 but it's not a fast diode.

    How to do ? B-E diode of a transistor is good instead of fast diode?
     
  2. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    A TL494 is a switchmode psu chipset not an Audio amplifier!
     
  3. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    @Dodgydave , They are using the TL494 as a class D modulator.
    @Motanache , You can not ommit the IR 2010, as it provides a boost converter to drive the upper mosfet.

    Bertus
     
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    Are you sure about that? I was under the idea the TL494 incorporated drivers internally to drive the mosfets directly?
     
  5. ronv

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    Nov 12, 2008
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    You can use the 1N4007 in place of the 914 diodes. If you have another small 12 volt power supply and some small transistors you could build your own driver.
     
  6. Motanache

    Thread Starter Member

    Mar 2, 2015
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    No, it has those two transistors as in the figure, which can be configured in any way.
     
  7. Motanache

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    Mar 2, 2015
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  8. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    1N914, 1N4148, are both the same high speed switching diodes,
     
  9. ronv

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  10. Motanache

    Thread Starter Member

    Mar 2, 2015
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    I started by building the voltage source.
    Also with TL494 because I really like this IC:
    [​IMG]
    The problem is that I thought wrong.
    I thought he had reverse polarity protection:):):)
    I built it, it works well ,but if you change the polarity of the input voltage it's something similar to the circuithort-circuited.
    It is normal for the IRFZ44 to have antiparallel diode.

    Do you know any cheaper solution than to use yet another power MOSFET for inverse polarity protection?
     
  11. ronv

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    Nov 12, 2008
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    VD1 should blow the fuse with reverse polarity.
    You could put that diode in series with the 12 volts depending on the current you need.
    I think all the FETs have the diode.
     
  12. Motanache

    Thread Starter Member

    Mar 2, 2015
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    It would be good to burn the fuse.
    But I'm afraid that first the power transistors(IRFZ44) are burn and then the fuse.
     
  13. ronv

    AAC Fanatic!

    Nov 12, 2008
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    Don't worry, be happy. :)
    The body diode has a high current rating and a higher voltage drop than your reverse protection diode.
     
  14. Motanache

    Thread Starter Member

    Mar 2, 2015
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    I'm done with the source.
    It works well, but Push-Pull it's a bit more expensive fhan Boost.

    With this schematic(Push-Pull) I got:
    70V on a resistance of 20R(a piece from a heater). P=U*U/R=aprox. 250W which is very good.

    The 12V was from a PC ATXpower supply. I used IRFZ44.

    I am pleased with the results, now move on to the amplifier:
    ------------------------------------------------------------------------------------------------------------------------------------------------------------------

    The following amplifiers intend to test them first at 12V And if all goes well to put them in a higher voltage.

    Prefrer the final stage to work in switching, To remove heat sink that is quite expensive.
    I would start with this seems quite simple:
    [​IMG]

    What I notice is that they do not have dead time.
    The bipolar transistor is even a slower switch than a correctly used MOSFET.

    I have seen correctly used transistors that remain cold at high power.
    I'm afraid that in this scheme it warm up a little and need a heat sink.

    Instead of 40106(NOT) I will use 4093(NAND).
    CA3110 is given at 15MHz. I'll try instead it LM386.
    It does not use a PWM with a given frequency, is a bit more weird amplifier.

    If anyone wants to explain how it works, please do it.
     
  15. ian field

    AAC Fanatic!

    Oct 27, 2012
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    Its theoretically possible - just because I never got around to trying it doesn't seem to have stopped someone else.

    Once I built a very nasty loud siren with full bridge speaker drive - the circuitry behind the power transistors was loosely based on the innards of that sort of chip.
     
  16. Motanache

    Thread Starter Member

    Mar 2, 2015
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    I'm done with the amplifier.
    Works well.
    I chose the version without feedback.

    I tested it at a low voltage, it should work if I increase the voltage.
     
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