i am looking for a design for a minimum component count buck converter for a special (and triple insulated) led lighting unit. the ideal circuit will rectify mains to 400v then chop it up at around 60-200khz and smooth it with no magnetic components. the output voltage must remain reasonably stable at an adjustable 80-150v at 4-8 Amps. there should be feedback from an ntc thermistor rather than constant current. temperature above 60c should automatically reduce power. mains side power factor correction is not needed as there will be several units back to back. its off grid but still running true sine wave 240v.
components need to be the most common world available parts such as 555 timers, standard mass use mosfets, etc and several mosfets can run in parallel. i repeat that this is a fully insulated unit and there should be no magnetics, high value capacitors, high cost or rare components. all must be off the shelf stuff or pull from scrap so the units can be built anywhere in the world without ordering overseas.
fusing and trips are already catered for. suggestions or complaints about safety are not welcome, nor are suggestions outside the above brief. no flames, no trolls, no "electronics police" type comments PLEASE!
best idea wins a prize
components need to be the most common world available parts such as 555 timers, standard mass use mosfets, etc and several mosfets can run in parallel. i repeat that this is a fully insulated unit and there should be no magnetics, high value capacitors, high cost or rare components. all must be off the shelf stuff or pull from scrap so the units can be built anywhere in the world without ordering overseas.
fusing and trips are already catered for. suggestions or complaints about safety are not welcome, nor are suggestions outside the above brief. no flames, no trolls, no "electronics police" type comments PLEASE!
best idea wins a prize