High Frequency power

Discussion in 'The Projects Forum' started by jester1, Mar 15, 2012.

  1. jester1

    Thread Starter Member

    Feb 10, 2011
    I'm trying to build a circuit using a 555 timer. The circuit needs to put out 450v at ~1.3MHz. Now my problem even with the transistor amp in the circuit it outputs 2.2v and with the transformer I have on hand the voltage going into it needs to be minimum 15v to get out the required 450v. Attached is a picture of the circuit and also a multisim design.
    Last edited: Mar 15, 2012
  2. Johnny B. Goode

    New Member

    Jun 14, 2010
    I am by no means an expert, but in your schematic both transistors are PNP. In the schematic you based on one is a NPN and the other a PNP. Your circuit is going to behave somewhat differently than the one you based it on.

    I would try driving the transformer off the collector of a single transistor. If you're driving it with a square wave from the 555 you might be able to just tie the base of the transistor to ground with a pull down resistor and get an inverted output(which shouldn't matter for driving a transformer).
  3. crutschow


    Mar 14, 2008
    What transformer do you have that's good to 1.3MHz?
  4. DickCappels


    Aug 21, 2008
    On the schematic, one is NPN and the other is PNP, but the part numbers are the same for both.

    Running as emitter followers is a good idea because it is very difficult to get bipolar transistors to switch fast enough to pump 1.3 MHz efficiently.

    As per Crutschow's comment, the transformer, with that many turns, would be very difficult to make with a low leakage inductance. A better approach might be to use capacitance to resonate at 1.3 MHz with the leakage inductance (an expert might be able to do that with only the parasitic capacitance) to achieve most of your voltage multiplication that way.

    You might want to try 13 kHz first, then work your way up.