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Using zener diode to protect test circuit?

J

Jim Thompson

Jan 1, 1970
0
Jim Thompson wrote...
[snip]

It works if you...
Tie input of upper inverter to lower "IN"
Tie input of lower inverter to upper "IN"
Cute! I'll use it ;-)

That's right, thanks! I messed-up when translating my first
drawing to the second one. Here's the corrected schematic.

. _Vdd ----- + out
. / |
. IN ---+--O< |--,
. | \_| | Active bridge rectifier
. unknown \________|_ using cmos hex inverters
. polarity ________| |
. / _ |
. | / | |
. IN ---+--O< |----'
. \_|
. Vss ----- - out

Again, someone must have invented this long ago. Sometime shortly
after the first cmos hex inverters came out in the mid 60s, or at
least soon after cmos became available in low-cost plastic packages
about 35 years ago... But now we can make it with a micro-miniature
ON Semi NL27WZ04 MiniGate™ in a SC70-6 package, a 2.1 x 2.1mm dust
flake. See http://www.onsemi.com/site/content/0,,1241,00.html and
http://www.onsemi.com/pub/Collateral/NL27WZ04-D.PDF

Using the FETs in a low-voltage cmos process allows us to use this
technique down to 1.5V or even less, although of course the FET's
on resistance goes up at low voltages. Has anyone seen an Ron vs
Vdd plot for these low-voltage logic families? ON Semi's NL17SV04
is claimed to work well at 0.9V supply, and deliver 50MHz at 1.2V.

BTW, although the fabulous MiniGate logic sample kit is no longer
available free from ON Semi, it's offered by DigiKey for only $39.
Search on MINIGATEA-KIT. Break out those microscopes!

I simulated it with basically a 74HCU04 structure (UNBUFFERED
Inverter).

That is a SINGLE inverter stage.

I don't know quite what it will do with a 74HC04 (each 'inverter' is
actually 3-stages long).

I'll try that next.

...Jim Thompson
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Jim Thompson
That _might_ work if the reverse voltage doesn't ever go above 6V, but
you're playing it awfully close to Absolute Maximum specification.

Are there any NPNs with a higher VEB(BR)? Aren't PNPs better for this
characteristic? A PNP in the 0V is worth an NPN in the +V, surely?
 
J

Jim Thompson

Jan 1, 1970
0
Jim Thompson wrote...
[snip]

It works if you...
Tie input of upper inverter to lower "IN"
Tie input of lower inverter to upper "IN"
Cute! I'll use it ;-)

That's right, thanks! I messed-up when translating my first
drawing to the second one. Here's the corrected schematic.

. _Vdd ----- + out
. / |
. IN ---+--O< |--,
. | \_| | Active bridge rectifier
. unknown \________|_ using cmos hex inverters
. polarity ________| |
. / _ |
. | / | |
. IN ---+--O< |----'
. \_|
. Vss ----- - out

Again, someone must have invented this long ago. Sometime shortly
after the first cmos hex inverters came out in the mid 60s, or at
least soon after cmos became available in low-cost plastic packages
about 35 years ago... But now we can make it with a micro-miniature
ON Semi NL27WZ04 MiniGate™ in a SC70-6 package, a 2.1 x 2.1mm dust
flake. See http://www.onsemi.com/site/content/0,,1241,00.html and
http://www.onsemi.com/pub/Collateral/NL27WZ04-D.PDF

Using the FETs in a low-voltage cmos process allows us to use this
technique down to 1.5V or even less, although of course the FET's
on resistance goes up at low voltages. Has anyone seen an Ron vs
Vdd plot for these low-voltage logic families? ON Semi's NL17SV04
is claimed to work well at 0.9V supply, and deliver 50MHz at 1.2V.

BTW, although the fabulous MiniGate logic sample kit is no longer
available free from ON Semi, it's offered by DigiKey for only $39.
Search on MINIGATEA-KIT. Break out those microscopes!

I simulated it with basically a 74HCU04 structure (UNBUFFERED
Inverter).

That is a SINGLE inverter stage.

I don't know quite what it will do with a 74HC04 (each 'inverter' is
actually 3-stages long).

I'll try that next.

...Jim Thompson

Interesting result is that the 74HC04 isn't as good as the simple
74HCU04 near zero, and has no better load capability since that is
limited by the rail voltage determining the gate voltage of the main
stage.

...Jim Thompson
 
W

Winfield Hill

Jan 1, 1970
0
Jim Thompson wrote...
Interesting result is that the 74HC04 isn't as good as the simple
74HCU04 near zero, and has no better load capability ...

For this test you'd have to trust your spice FET models near 0V,
which as we've discussed is in the subthreshold zone, where most
models are notoriously faulty. 'U04 parts are popular for linear
amplification, etc, where the spice modeling issue also comes up.
One step in evaluating a model is to measure the transfer function
of some real n- and p-channel parts, which either Paul or I will
do for some ON Semi low-voltage unbuffered MiniGate inverters in
the next few days. It's a continuation of what I started with
the 2n7000 and some other JFETs and power mosfets.
 
J

Jim Thompson

Jan 1, 1970
0
Jim Thompson wrote...

For this test you'd have to trust your spice FET models near 0V,
which as we've discussed is in the subthreshold zone, where most
models are notoriously faulty. 'U04 parts are popular for linear
amplification, etc, where the spice modeling issue also comes up.
One step in evaluating a model is to measure the transfer function
of some real n- and p-channel parts, which either Paul or I will
do for some ON Semi low-voltage unbuffered MiniGate inverters in
the next few days. It's a continuation of what I started with
the 2n7000 and some other JFETs and power mosfets.

I modeled this with X-FAB CMOS (integrated circuit) models which DO
model sub-threshold.

I know that they work... I'm in a hearing aid project where virtually
everything is operated sub-threshold. And also VERY noisy :-(

I'm using PSpice Level=7 / HSpice Level=49, none of this Level=3 shit
for me... they only do modeling that crufty for discretes.

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
Jim Thompson wrote...

For this test you'd have to trust your spice FET models near 0V,
which as we've discussed is in the subthreshold zone, where most
models are notoriously faulty. 'U04 parts are popular for linear
amplification, etc, where the spice modeling issue also comes up.
One step in evaluating a model is to measure the transfer function
of some real n- and p-channel parts, which either Paul or I will
do for some ON Semi low-voltage unbuffered MiniGate inverters in
the next few days. It's a continuation of what I started with
the 2n7000 and some other JFETs and power mosfets.

See...

Newsgroups: alt.binaries.schematics.electronic
Subject: Active bridge rectifier using cmos hex inverters (from S.E.D)
- WinsRectifierHCU04.pdf
Message-ID: <[email protected]>

I forgot that, in May 1997, I had redesigned ON-Semi's unbuffered
inverter (...U04) to fit their change to Chartered Semiconductor's
foundry.

...Jim Thompson
 
W

Winfield Hill

Jan 1, 1970
0
Jim Thompson wrote...
I modeled this with X-FAB CMOS (integrated circuit) models which
DO model sub-threshold.

I know that they work... I'm in a hearing aid project where virtually
everything is operated sub-threshold. And also VERY noisy :-(

I'm using PSpice Level=7 / HSpice Level=49, none of this Level=3
shit for me... they only do modeling that crufty for discretes.

This is good, and I envy you your model, but it should still
somehow be verified as correct for the parts we're able to buy.
 
That _might_ work if the reverse voltage doesn't ever go above 6V, but
you're playing it awfully close to Absolute Maximum specification.
Maybe put a diode in the base lead to gain an extra 0.7 volts of
protection. Since it's a 5V input, that might just be enough to make
it perfectly safe.

Stepan
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Jim Thompson
<[email protected]>) about 'Active bridge
rectifier using cmos hex inverters, was Using zener diode to protect
test circuit?', on Sun, 24 Apr 2005:

WARNING!!!! Norton AV found W32.Beagle.AG@mm virus in this message and
has removed it. Virus scanning of outgoing messages is in force here.
 
J

Jim Thompson

Jan 1, 1970
0
I read in sci.electronics.design that Jim Thompson
<[email protected]>) about 'Active bridge
rectifier using cmos hex inverters, was Using zener diode to protect
test circuit?', on Sun, 24 Apr 2005:

WARNING!!!! Norton AV found W32.Beagle.AG@mm virus in this message and
has removed it. Virus scanning of outgoing messages is in force here.
[snip]

What version of NAV are you using?

If it was really there it got there from something in your machine or
news server.

I run the latest version of NAV, and am a paid subscriber to the
automatic (almost daily) updates.

I just scanned the original here and it shows no problems.

I also scanned a downloaded copy to see if a virus was somehow
inserted.... neeeeerp!

I also run SpyBot, ScanSpyware and AdAware at least once a week; plus
I have a hardware firewall, so I think I have a clean machine ;-)

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
I read in sci.electronics.design that Jim Thompson
<[email protected]>) about 'Active bridge
rectifier using cmos hex inverters, was Using zener diode to protect
test circuit?', on Sun, 24 Apr 2005:

WARNING!!!! Norton AV found W32.Beagle.AG@mm virus in this message and
has removed it. Virus scanning of outgoing messages is in force here.
[snip]

John, I just realized that you referenced a text message. Where's the
virus ?:)

...Jim Thompson
 
J

Jim Thompson

Jan 1, 1970
0
Maybe put a diode in the base lead to gain an extra 0.7 volts of
protection. Since it's a 5V input, that might just be enough to make
it perfectly safe.

Stepan

Naaah! You'd still have BVCEOrev back thru from the load

...Jim Thompson
 
W

Winfield Hill

Jan 1, 1970
0
Jim Thompson wrote...
See...

Newsgroups: alt.binaries.schematics.electronic
Subject: Active bridge rectifier using cmos hex inverters
(from S.E.D)- WinsRectifierHCU04.pdf
Message-ID: <[email protected]>

I forgot that, in May 1997, I had redesigned ON-Semi's unbuffered
inverter (...U04) to fit their change to Chartered Semiconductor's
foundry.

That's very nice, can you show us the spice-model code?
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Jim Thompson
<[email protected]>) about 'Active bridge
rectifier using cmos hex inverters, was Using zener diode to protect
test circuit?', on Sun, 24 Apr 2005:
I read in sci.electronics.design that Jim Thompson
<[email protected]>) about 'Active bridge
rectifier using cmos hex inverters, was Using zener diode to protect
test circuit?', on Sun, 24 Apr 2005:

WARNING!!!! Norton AV found W32.Beagle.AG@mm virus in this message and
has removed it. Virus scanning of outgoing messages is in force here.
[snip]

What version of NAV are you using?

2004 V7.0 Build 81 Automatic updates enabled
If it was really there it got there from something in your machine or
news server.

That's rather what I suspected. It's not on my machine. But I thought it
best to send a warning, just in case.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Jim Thompson
<[email protected]>) about 'Active bridge
rectifier using cmos hex inverters, was Using zener diode to protect
test circuit?', on Sun, 24 Apr 2005:
John, I just realized that you referenced a text message. Where's the
virus ?:)

I couldn't see it as an attachment or anything, but then I don't know
whether a virus can now (e.g. as of today!) hide itself in some way. I
wasn't motivated to try too many experiments before I let Norton kill
it.
 
J

Jim Thompson

Jan 1, 1970
0
Jim Thompson wrote...

That's very nice, can you show us the spice-model code?

Sure. It's been 8 years, so it's out of NDA...

Subject: Re: Active bridge rectifier using cmos hex inverters (from
S.E.D) - WinsRectifierHCU04.pdf - CharterModels.zip
Message-ID: <[email protected]>
References: <[email protected]>

...Jim Thompson
 
Naaah! You'd still have BVCEOrev back thru from the load
Would a few hundred nanofarads worth of decoupling caps in the load
matter though? I know that certain things like LEDs can be damaged by
very low reverse currents due to localized heating in the die, due to
non-uniform reverse breakdown over the entire junction, but is that
the case for transistor be junction?

stepan
 
Would a few hundred nanofarads worth of decoupling caps in the load
matter though? I know that certain things like LEDs can be damaged by
very low reverse currents due to localized heating in the die, due to
non-uniform reverse breakdown over the entire junction, but is that
the case for transistor be junction?
I should have mentioned that there aught not be much charge left on
the decoupling caps by the time you disconnect and re-connect the
circuit. So I wonder how much abuse an EB junction can take. Yes, I
don't think anyone would want to see an electrolytic in there.

Stepan
 
J

Jim Thompson

Jan 1, 1970
0
Why not use a zener instead of R1, R2, DZ1? The only thing I noticed
when simulating with LTSPICE was the power dissipation at R3 at 5V.

You OUGHT to know the answer to that... zeners aren't worth the powder
to blow 'em to hell when they're under 5V.

...Jim Thompson
 
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