Traingle wave generator IC

Discussion in 'The Projects Forum' started by k2n2a2, Oct 1, 2012.

  1. k2n2a2

    Thread Starter Member

    Jul 16, 2012
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    1
    Hello,

    I am looking for an IC that generates triangular wave with frequency range from 1KHz to 100KHz. I looked at many ICs and the thing I didn't like is that the frequency is set either through a fixed resistor or a pot.
    Is there a triangle wave generator chip whose frequency can be set/adjusted through an analog voltage directly.

    Thank you.
     
  2. Papabravo

    Expert

    Feb 24, 2006
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    I don't think so. There used to be a handful of function generator chips, but they have been obsolete for a decade or more. They are available on auction sites for princely sums. My suggestion is to build one from basic parts by integrating the output of a square wave VCO.

    You might also try DDS (Direct Digital Synthesis) with a first order hold.
     
  3. wayneh

    Expert

    Sep 9, 2010
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    +1 Another, sloppier approach would be to use the voltage on top of a 555's timing capacitor. IT's not quite a triangle but awfully close for most uses.
     
  4. BMorse

    Senior Member

    Sep 26, 2009
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  5. Wendy

    Moderator

    Mar 24, 2008
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    Do you need a symmetrical triangle wave, or will a linear ramp work? There are 555 circuits that will do this.

    [​IMG]

    Here is what the earlier post was alluding to:

    [​IMG]
     
  6. k2n2a2

    Thread Starter Member

    Jul 16, 2012
    37
    1
    yes, I am looking for a symmetrical tri-wave, to be used a part of a PWM generator.
     
  7. Wendy

    Moderator

    Mar 24, 2008
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    PWM does not need a symmetrical triangle wave.

    Pulse Width Modulation

    Something I wrote for the AAC book.
     
  8. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  9. t06afre

    AAC Fanatic!

    May 11, 2009
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    I have used this AD5932. It also looks like NTE is selling rebranded ICL8038 under the name of NTE864. It's daylight robbery to charge that amount of money for that chip although
    http://www.datasheetdir.com/NTE864+download
     
  10. Wendy

    Moderator

    Mar 24, 2008
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    Especially when there are many ways to skin this cat. If the OP finds what I have shown unacceptable I can dig up other circuits. Triangle waves are both easy and bread and butter to electronics.
     
  11. Papabravo

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    Feb 24, 2006
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  12. crutschow

    Expert

    Mar 14, 2008
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    So why do you need a voltage controlled frequency? :confused:
    PWM is normall fixed frequency with variable duty-cycle.
     
  13. k2n2a2

    Thread Starter Member

    Jul 16, 2012
    37
    1
    well, both the PWM frequency and duty cycle need to be controlled, because this PWM will control a high voltage pulse generator, which need to operate at different frequencies as well as different duty cycles.
     
  14. t06afre

    AAC Fanatic!

    May 11, 2009
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    The ICL8038 could be used as a VCO. And the NTE IC I pointed you to. Is in fact a ICL8038. If this is some one of i kind project. I say why not get some ICL8038 from EBAY. Better than getting the same chip from NTE
     
    k2n2a2 likes this.
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