Could some electronics guru shed some light on the following ? Normally, when we think of a bridge rectifier, input signal frequencies of 50/60 Hz come to mind. How high could the input frequencies rise? Is there some limit ? Thanks in advance for your help.
I'm using an ordinary bridge for 8 kHz, but it seems to be rather=20 inefficient. So I searched for Schottky bridges, and found some that = should=20 be a lot better:
No specs on frequency or recovery time.
If 28V and 200mA are OK, here is a little one SOT-143:
But also no frequency specs.
A comparable product from TI shows 15-30 nSec recovery. That's pretty=20 fast...
Paul=20
"Daku"
** Ordinary power diodes get hotter as the frequency rises above about 1kHz. ** Package temps over 100C are not wise.At frequencies of 10kHz or more, folk generally go for bridges made from high speed diodes.
... Phil
ld
/CBRHDSH2-10...
Actually, Vishay claims on its Web site that it has < 10 nanosecond reverse recovery time diodes.
A bridge rectifier is typically a set of four diodes of arbitrary specification. So, no, there ain't no limit on the bridge...just the diodes...read the spec. You can make one hell of a fast diode bridge out of 1N21 diodes. And that's 60 or more years old technology.
If you mean, bridge rectifier as a packaged diode quad optimized for 60 Hz., then, yes, there are issues that depend on the individual diodes in the package...'cause they're optimized for cost when used at 60 Hz....read the spec.
You're working the problem backwards. Decide what frequencies you need, voltages and currents, how much loss you can tolerate, how much heat you can get rid of, how much EMI you can tolerate, whether your input is sine wave or not. Then figger out the specs of the bridge you need. Then RTFM to determine whether you can afford the diodes that meet your spec. Junction capacitance and reverse recovery time are two relevant specs.
No, it's not a simple question.
Double balanced mixers use diodes. (in a ring) I've got a low frequncy one from mini-circits that's good to 200MHz. I'm sure they go higher. (But maybe stop using diodes?)
George H.
This is running at about 90 KHz. Works fine.
ftp://jjlarkin.lmi.net/ESM_power.pdf
D2 and D3 are little surface-mount schottky bridge rectifiers.
There's no fundamental limit on bridge frequency. Schottky diodes work into the GHz.
John
(Note that this is a real, working schematic, with parts values.)
Some sampling scopes used 4-diode bridge samplers. The Tek 7S14 did, and got about 2 GHz bandwidth using a potted bridge rectifier. Weird design.
John
Of course, this "potted bridge rectifier" was made with some relatively exotic (I think Tek-made) Schottky diodes... not an off-the-shelf part.
Like others have posted, the bridge architecture has no inherent upper frequency limits. The freq. limit would be based on the parasitics of the individual bridge diodes, plus component layout at higher frequencies.
Some of those big high current, high reverse voltage rectifiers might only be good for 10s or 100s of kHz.
-- Paul Hovnanian mailto:Paul@Hovnanian.com ------------------------------------------------------------------ What if no one ever asked a hypothetical question?
Yup. A full-wave diode rectifying bridge is a close topological cousin to the diode ring used in double-balanced mixers, and these are frequently used at switching (local-oscillator) frequencies up in to the high MHz range.
It really all depends on the diodes.
A lot of the common power-rectifier diodes (e.g. 1N400x family) have a PIN structure, and are relatively slow to shut off in the face of reverse bias... they've got a long carrier lifetime. I suspect that many common power-rectification bridges use diodes of a similar nature.
You can buy power-rectification bridges made out of HEXFRED or similar fast-recovery diodes (see
--
Dave Platt AE6EO
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Here is a link showing how the recovery time can be measured. In = particular,=20 it shows that a common 1N4004 diode has a t(rr) of 1.2 uSec. So it would = be=20 unusable at 1 MHz, perhaps have 10% switching losses at 100 kHz, but = should=20 be fine for most audio purposes up to 20-30 kHz or so. Larger bridge=20 rectifiers over 1 amp are likely to be worse, but it is difficult to = find=20 the specs since they are usually optimized for 50/60/400 Hz where = switching=20 time is largely irrelevant.
I was surprised to find Schottky bridges that handle 2 amps and 100V for =
less than a buck:
Switching time is not specified, but is likely to be about as good as = the=20
1N5818. This is also not specified, because the usefulness is more a = factor=20 of junction capacitance, which in this case (20-200pF) limits use to 1 = or 2=20 MHz:Paul=20
Sadly from an ftp site I cannot access :( Not my end 'cos I downloaded >2GB from mirror.aarnet.edu.au last week using wget for windows on Win7.
But there's a workaround :o) Search for the file in google, select 'quick view', then file, Download original, if you like to view in local .pdf viewer.
But I didn't see the 555! ;)
Grant.
snipped-for-privacy@grrr.id.au wrote in news: snipped-for-privacy@4ax.com:
I suspect junction capacitance of the schottky diode may have some effect on operation.
Power diodes are different than small-signal diodes.
-- Jim Yanik jyanik at localnet dot com
These are cute, only 100 pF or so.
61.222.192.61/mccsemi/up_pdf/MB12S-MB110S(MBS-1).pdfJohn
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