3 ms·
My favorite cute hack of a power supply is the ringing choke converter (self-oscillating flyback). It doesn't require any controller ICs, just a couple of trans
by SAI_Peregrinus 9y ago
My favorite cute hack of a power supply is the ringing choke converter (self-oscillating flyback). It doesn't require any controller ICs, just a couple of transistors, resistors, caps, and a transformer. You get isolation, and the circuit is quite simple. With an optoisolator and zener diode you can even get regulated output!
The disadvantages are the poor efficiency, need for tuning, and need for a transformer if you don't need the isolation. Also no programming involved, so not really of as much interest to most of the HN community.
- blackguardx 9y agoThat was the first circuit I put together after cobbling together some old TV parts in 8th grade. The noise and dazzling purple glow of the high voltage arc from the flyback transformer were mesmerizing. The urge to understand how it worked led me to study EE in college.
- kens 9y agoIf you buy a $2 phone charger, this circuit (the ringing choke converter) is what you get. It's kind of amazing how cheaply these are made. It can look just like an Apple charger on the outside, but the power quality (and safety) is much, much worse.
- SAI_Peregrinus 9y agoYep, they're used in lots of cheap power supplies, not just phone chargers. The poor power quality and safety aren't inherent problems of the ringing choke design, those are just issues with cheap chargers. They tend to omit the output filtering and do horrible things to creepage and clearance distances.
- userbinator 9y agoAll the controller ICs do is put almost everything but the coil onto one silicon die. Otherwise they work similar to the discrete version.