22-12-2016, 05:30 PM
Thanks to Trevor and Greg for their help with this, there was no one single fix. But further experimentation with the circuit has made it stable and repeatable.
More than half the alpha test examples failed to work properly, found unfortunately after the PCB's had been commissioned.
Greg, (new member "reset") had done a spice simulation, concentrating on the decoupling of the base bias of the converter transistor, he has posted his findings in his blog, http://radio.radiotrician.org/2016/12/us...g.html?m=1 Combining Trevor and Greg's suggestions with a little resistive damping of the feedback has resulted in a circuit that has worked 100% with fifty examples of the 9018 transistor.
Thanks to you both,
Andy.
More than half the alpha test examples failed to work properly, found unfortunately after the PCB's had been commissioned.
Greg, (new member "reset") had done a spice simulation, concentrating on the decoupling of the base bias of the converter transistor, he has posted his findings in his blog, http://radio.radiotrician.org/2016/12/us...g.html?m=1 Combining Trevor and Greg's suggestions with a little resistive damping of the feedback has resulted in a circuit that has worked 100% with fifty examples of the 9018 transistor.
Thanks to you both,
Andy.
