https://www.dropbox.com/scl/fo/cx2tgk4xexj134kck54js/h?rlkey=qrp95nd26g5zy2bjqce1k5pfa&dl=0 Diodes Inc AP63300. This will switch +48 down to 5/12/24 or whatever. I tested it because sometimes synchronous switchers make horrendous noise spikes, but this looks pretty good. The trick seems to be to tweak the doping so the substrate diode isn't an SRD.
cute little switcher
Started by ●September 20, 2023
Reply by ●September 21, 20232023-09-21
On a sunny day (Wed, 20 Sep 2023 11:33:39 -0700) it happened John Larkin <jl@997PotHill.com> wrote in <64cmgitdu9m6hrobm7rqllkagba0cjkdnq@4ax.com>:>https://www.dropbox.com/scl/fo/cx2tgk4xexj134kck54js/h?rlkey=qrp95nd26g5zy2bjqce1k5pfa&dl=0 > >Diodes Inc AP63300. This will switch +48 down to 5/12/24 or whatever. >I tested it because sometimes synchronous switchers make horrendous >noise spikes, but this looks pretty good. The trick seems to be to >tweak the doping so the substrate diode isn't an SRD.OK second harmonic 1 MHz in the medium wave radio band...
Reply by ●September 21, 20232023-09-21
On Thu, 21 Sep 2023 05:14:10 GMT, Jan Panteltje <alien@comet.invalid> wrote:>On a sunny day (Wed, 20 Sep 2023 11:33:39 -0700) it happened John Larkin ><jl@997PotHill.com> wrote in <64cmgitdu9m6hrobm7rqllkagba0cjkdnq@4ax.com>: > >>https://www.dropbox.com/scl/fo/cx2tgk4xexj134kck54js/h?rlkey=qrp95nd26g5zy2bjqce1k5pfa&dl=0 >> >>Diodes Inc AP63300. This will switch +48 down to 5/12/24 or whatever. >>I tested it because sometimes synchronous switchers make horrendous >>noise spikes, but this looks pretty good. The trick seems to be to >>tweak the doping so the substrate diode isn't an SRD. > >OK >second harmonic 1 MHz in the medium wave radio band...Switchers do that. I like the old Simple Switchers that run at 50 KHz, but they need a catch diode and gigantic inductors and capacitors. One of our products just/finally passed the CE EMI tests, after 6 expensive EMI lab visits. That has a front-end isolated switching supply running at 100 KHz. The failure was conducted EMI on the 24 volt input, which makes no sense since that's deep inside a big system. Fortunately, our cusomer paid for the testing.
Reply by ●September 21, 20232023-09-21
On Thursday, September 21, 2023 at 7:21:44 AM UTC-7, John Larkin wrote:> >second harmonic 1 MHz in the medium wave radio band... > Switchers do that. I like the old Simple Switchers that run at 50 KHz, > but they need a catch diode and gigantic inductors and capacitors. >Looks like this one can run at any desired rate up to 2.5 MHz, similar to the LT parts. It does look like a good alternative.> One of our products just/finally passed the CE EMI tests, after 6 > expensive EMI lab visits. That has a front-end isolated switching > supply running at 100 KHz. The failure was conducted EMI on the 24 > volt input, which makes no sense since that's deep inside a big > system.Ouch. I thought I was being clever by using an LT3086 as a preregulator just behind the power entry jack on one box, running with about 1V of dropout headroom. No problem passing FCC/CE. Sailed right through. But it was sure as hell a problem when LT decided to stop shipping LT3086IRs for a year or so. :(
Reply by ●September 22, 20232023-09-22
On a sunny day (Thu, 21 Sep 2023 07:21:26 -0700) it happened John Larkin <jl@997arbor.com> wrote in <qvjogilaue84p27va21p324m9kgnsm3p53@4ax.com>:>On Thu, 21 Sep 2023 05:14:10 GMT, Jan Panteltje <alien@comet.invalid> >wrote: > >>On a sunny day (Wed, 20 Sep 2023 11:33:39 -0700) it happened John Larkin >><jl@997PotHill.com> wrote in <64cmgitdu9m6hrobm7rqllkagba0cjkdnq@4ax.com>: >> >>>https://www.dropbox.com/scl/fo/cx2tgk4xexj134kck54js/h?rlkey=qrp95nd26g5zy2bjqce1k5pfa&dl=0 >>> >>>Diodes Inc AP63300. This will switch +48 down to 5/12/24 or whatever. >>>I tested it because sometimes synchronous switchers make horrendous >>>noise spikes, but this looks pretty good. The trick seems to be to >>>tweak the doping so the substrate diode isn't an SRD. >> >>OK >>second harmonic 1 MHz in the medium wave radio band... > >Switchers do that. I like the old Simple Switchers that run at 50 KHz, >but they need a catch diode and gigantic inductors and capacitors. > >One of our products just/finally passed the CE EMI tests, after 6 >expensive EMI lab visits. That has a front-end isolated switching >supply running at 100 KHz. The failure was conducted EMI on the 24 >volt input, which makes no sense since that's deep inside a big >system. > >Fortunately, our cusomer paid for the testing. >Yes it makes ense to filter all in and out going power line.
