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I am working on a wireless power transfer project using, I need to design an oscillator. I need a frequency of over 2MHz and I need it for a high power application.

So my question is what is the maximum value of voltage I can apply as \$V_{CC}\$. Does it depend on what the oscillator uses, i.e BJT, MOSFET, or an op amp?

Any suggestions and solutions are welcome.

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  • \$\begingroup\$ You can use a transformer to increase the voltage. What sort's of voltages and currents do you need? \$\endgroup\$ Jan 20, 2015 at 15:04
  • \$\begingroup\$ generating high voltage is not the problem. I wanted to know how to find the oscillator's limits(max voltage) \$\endgroup\$
    – Quadphazer
    Jan 20, 2015 at 15:14
  • \$\begingroup\$ I've got a ~60 MHz oscillator that runs off of 28V but has a auto transformer on the output and so delivers ~150 Vp-p. \$\endgroup\$ Jan 20, 2015 at 15:27
  • \$\begingroup\$ The AC voltage on an LC oscillator can be much greater than the supply voltage. \$\endgroup\$ Jan 20, 2015 at 17:41

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The maximum voltage you can apply as Vcc is going to restricted by the limits of the components in the circuits.

I.e. oscillators that use op amps will be restricted by the op amp's maximum supply voltage and input voltage, go too high and you'll fry the op amp. You can get op amps which can handle large voltages, you'll just have to search for them on a distributors website (like element14 or rscomponents) and they may cost more than your regular op amps.

Same goes for any other active component like mosfets and BJTs, though they may also be subject to current limits too.

However, for a high power application, you can only increase the voltage so far, and you're unlikely to find op amps that can handle 1000KV. What you need to do is also increase the current flowing into your antenna, the same way you need to increase the current going into speakers to increase the power.

A better solution is generate your oscillations and then pass them into a current or "power" amplifier to drive your antenna or load.

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  • \$\begingroup\$ ok so referring the datasheet of the device used, i.e op amp, fet would be enough? \$\endgroup\$
    – Quadphazer
    Jan 20, 2015 at 15:12
  • \$\begingroup\$ I am going to work on a maximum of 230 volts DC. I had this confusion because all the circuits i refered to had 5-12 volts Vcc. \$\endgroup\$
    – Quadphazer
    Jan 20, 2015 at 15:15
  • \$\begingroup\$ It may not be enough but it's the best place to start. You'll also want to look at the output current limits - This will affect the amount of power you're able to get out immediately (i.e. before putting a power amplifier on the output) \$\endgroup\$
    – Sarrk
    Jan 20, 2015 at 15:17
  • \$\begingroup\$ what do u suggest i start testing with? op amp or BJT's? i am just exploring oscillators, for the first time practically \$\endgroup\$
    – Quadphazer
    Jan 20, 2015 at 15:25
  • \$\begingroup\$ Start with an op amp. They will be the easiest to work with. If you are just exploring oscillators, there is no need to achieve a final high voltage right now, 5V is a good Vcc to start with which should be compatible with general purpose op amps. Look at some classic oscillators if you haven't already, the Wein Bridge is one that comes to mind. You will then need to look into buffers or ways to scale up a low level oscillated voltage into a high level one. Sorry I am no telecommunications engineer so I cannot help with this one. \$\endgroup\$
    – Sarrk
    Jan 20, 2015 at 15:49

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