cute little switcher...

[John Larkin]

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.

 

[Jan Panteltje]

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...

 

[John Larkin]

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.

 

[John Miles, KE5FX]

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.

 

[Jan Panteltje]

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.