I was experimenting with a low watt boost converter,12V to 100V,50mA using the venerable MC34063A and an external MOSFET switch..I calculated the inductor value to be about 100uH.So I made two inductors using a drum core and toroid ring,both of which are 100uH.The drum core works well,but under load the toroid drops to 60V or so. Is the toroid saturating? If so ,should i use a larger toroid to overcome this problem? TIA.
A 5:1 ratio is already on top of what is possible with a simple boost converter. The turn-off time of your switch has to be extremely short for higher ratios, otherwise you won't get a high boost. A flyback topology is often simpler to implement.