@gregebert: Yes, I ordered a switching regulator. The 6.3V AC just happens to be available on the transformer I am using for other purposes.
@jfeng: I am tending to agree that an isolated 5V power adapter is the way to go, particularly as I will want the logic circuits to stay functioning even if I disconnect the mains transformer. However, as an exercise, this is turning out to be more interesting than I thought, so I will pursue it for a while longer. Not sure if I'm up for building my own buck/boost converter. Yet. On Sunday, March 24, 2019 at 10:46:22 AM UTC-4, Paul Andrews wrote: > > I want to create a 5V/1A regulated power supply from a 6.3V RMS input. I > can get a regular diode bridge in a 4 pin DIP package, but it is marginal > and my simulations and actual tests show that the forward voltage drop is > too much under even a light load. My simulations show that a Schottky diode > bridge works OK, and I can get an SMD 4 pin package with a total forward > voltage drop of around 0.8V. However, I have seen designs for active MOSFET > full-wave rectifiers, so I figured I might as well try to go that route. > > I came across two potential ICs to help. One is the LT4320 and the other > is the FDMQ8205. The LT4320 uses external FETs, but the killer seems to be > that the minimum output voltage is 9V. The FDMQ8205 has internal FETs, but > I can't figure out how I would use it in a regular full-wave bridge > rectifier. It has AC inputs and gate drive inputs and I'm not sure what the > gate drive inputs should be. In note 4 in the datasheet > <https://www.onsemi.com/pub/Collateral/FDMQ8205-D.pdf>they show a wiring > diagram that connects the AC input to the gate inputs, but I can't tell if > that is a topology that would provide full wave rectification, or if it is > just something used for testing. > > Does anyone have any experience with active bridges at these voltages, or > with these ICs? Is there an alternative I should be looking at? Should I > just stick with the Schottky diode version? > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/1b3bcfc4-b48a-4f8f-be82-ccaa77bdcbdf%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
