I'm trying to find an IC that can transform an analog signal (ranging from -18 to -18v) to PWM, ideally on two different pins (one for 0 to 18 and another for 0 to -18).

I can do this with something similar to this this, but I'd like something more compact. I found TL594, but I don't know if it will do.

What other options do I have?


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    \$\begingroup\$ Take opamp to generate sawtooth waveform and two comparators. Actually 555 may do it. \$\endgroup\$ – Gregory Kornblum Jul 14 '17 at 20:54
  • \$\begingroup\$ but is there an IC that can do this? I want to save space on my board. \$\endgroup\$ – user169808 Jul 14 '17 at 23:17
  • \$\begingroup\$ Are the -18v and 18v readily available? Or must the IC produce that too? And fyi, this is very very much like another question that was asked like a couple of hours ago. electronics.stackexchange.com/questions/317458/… \$\endgroup\$ – Harry Svensson Jul 15 '17 at 1:22
  • \$\begingroup\$ linear.com/product/LTC6992-1, you'll have add a divider for +-18V to 0-1 V \$\endgroup\$ – sstobbe Jul 15 '17 at 2:47
  • \$\begingroup\$ -18 and 18 is the signal to be transformed into pwm (18v = 100% pwm and 0v 0% pwm) \$\endgroup\$ – user169808 Jul 15 '17 at 3:13

Have a look at Linear's LTC6992.

enter image description here

You would need to attenuate your positive signal to < 1 V and you would need to attenuate and invert your negative signal into a second chip.

  • \$\begingroup\$ Hmm. Why the downvote? Have I missed something in the question? \$\endgroup\$ – Transistor Jul 15 '17 at 11:06
  • \$\begingroup\$ Not sure why downvote, add a 10k & 170k divider and its job done for positive half \$\endgroup\$ – sstobbe Jul 16 '17 at 16:10
  • \$\begingroup\$ no idea why as well, thanks for the suggestion, is it possible to change the reference in the ltc6992 (like an offset) \$\endgroup\$ – user169808 Jul 16 '17 at 18:02
  • \$\begingroup\$ Expand your original question a bit. Draw a graph with -18 to +18 on the X-axis and PWM 0 to 100% on the Y-axis. Then draw two curves for your desired outputs. You may find that you see the solution as you do it. \$\endgroup\$ – Transistor Jul 16 '17 at 18:10
  • \$\begingroup\$ yes, but I'd like to know if I can move the 0v on this graph left or right eg: 9v gets pwm 90% (or pwm 10%). from page 13 of the datasheet it seems as if I can't, but I'd like to be sure. \$\endgroup\$ – user169808 Jul 16 '17 at 19:39

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