Strange transistor driver circuit

"Jim Thompson" <thegreatone@example.com> a écrit dans le message de
news:2br0a1lod1os4snmf9p5daho45o2gs9lfr@4ax.com...
On Fri, 3 Jun 2005 16:35:41 +0200, "Fred Bartoli"
fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:

[snip]


Then I invent this one :

.-----------+-----+-----
| | |
|< |< |
----| .---| |
|\ | |\ |
| | | |
| |/ | |/
'---| '---|
|> |
| |
'-----------+-----

which has an even more huge HFE, uses an NPN as the power element and
allow
a lower VCEsat (NPN power element).

It is very pompously named a smartlington.

And VCEsat=??
Click to expand...
Certainly lower than for the 3 transitors PNP version.

For example, from the moto 3055/2955 datasheet, VBEsat @ 7A is 1.3V for the
NPN vs 1.6V for the PNP.

Allow, say 150/200mV VCEsat for the driver and you have 1.5V vs 1.8V.

The "input stages" will work nicely at 1.5V and won't contribute anything to
VCEsat.


This obviously don't hold if you need a power NPN. Just revert to the 3
transistors circuit.


--
Thanks,
Fred.
 
On Fri, 3 Jun 2005 17:04:25 +0200, "Fred Bartoli"
<fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:

"Jim Thompson" <thegreatone@example.com> a écrit dans le message de
news:2br0a1lod1os4snmf9p5daho45o2gs9lfr@4ax.com...
[snip]

And VCEsat=??


Certainly lower than for the 3 transitors PNP version.

For example, from the moto 3055/2955 datasheet, VBEsat @ 7A is 1.3V for the
NPN vs 1.6V for the PNP.

Allow, say 150/200mV VCEsat for the driver and you have 1.5V vs 1.8V.

The "input stages" will work nicely at 1.5V and won't contribute anything to
VCEsat.


This obviously don't hold if you need a power NPN. Just revert to the 3
transistors circuit.
Click to expand...
Just making sure you really understood the drops. Of course these
configurations are butt-slow on turn-off.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On Fri, 3 Jun 2005 16:35:41 +0200, the renowned "Fred Bartoli"
<fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:

Then I invent this one :

.-----------+-----+-----
| | |
|< |< |
----| .---| |
|\ | |\ |
| | | |
| |/ | |/
'---| '---|
|> |
| |
'-----------+-----

which has an even more huge HFE, uses an NPN as the power element and allow
a lower VCEsat (NPN power element).

It is very pompously named a smartlington.
Click to expand...
"Bartlington"


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On Fri, 03 Jun 2005 12:04:19 -0400, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

On Fri, 3 Jun 2005 16:35:41 +0200, the renowned "Fred Bartoli"
fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:


Then I invent this one :

.-----------+-----+-----
| | |
|< |< |
----| .---| |
|\ | |\ |
| | | |
| |/ | |/
'---| '---|
|> |
| |
'-----------+-----

which has an even more huge HFE, uses an NPN as the power element and allow
a lower VCEsat (NPN power element).

It is very pompously named a smartlington.

"Bartlington"


Best regards,
Spehro Pefhany
Click to expand...
Barfington ?:)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"Jim Thompson" <thegreatone@example.com> a écrit dans le message de
news:6sv0a15gu57r6oad2ues7ddkv0nd55ue1j@4ax.com...
On Fri, 03 Jun 2005 12:04:19 -0400, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:

On Fri, 3 Jun 2005 16:35:41 +0200, the renowned "Fred Bartoli"
fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:


Then I invent this one :

.-----------+-----+-----
| | |
|< |< |
----| .---| |
|\ | |\ |
| | | |
| |/ | |/
'---| '---|
|> |
| |
'-----------+-----

which has an even more huge HFE, uses an NPN as the power element and
allow
a lower VCEsat (NPN power element).

It is very pompously named a smartlington.

"Bartlington"


Best regards,
Spehro Pefhany

Barfington ?:)
Click to expand...
I knew you were so nice.


--
Thanks,
Fred.
 
"Jim Thompson" <thegreatone@example.com> a écrit dans le message de
news:kjs0a1t6abkm0rpsg4lafcbke0luba0acs@4ax.com...
On Fri, 3 Jun 2005 17:04:25 +0200, "Fred Bartoli"
fred._canxxxel_this_bartoli@RemoveThatAlso_free.fr_AndThisToo> wrote:


"Jim Thompson" <thegreatone@example.com> a écrit dans le message de
news:2br0a1lod1os4snmf9p5daho45o2gs9lfr@4ax.com...
[snip]

And VCEsat=??


Certainly lower than for the 3 transitors PNP version.

For example, from the moto 3055/2955 datasheet, VBEsat @ 7A is 1.3V for
the
NPN vs 1.6V for the PNP.

Allow, say 150/200mV VCEsat for the driver and you have 1.5V vs 1.8V.

The "input stages" will work nicely at 1.5V and won't contribute anything
to
VCEsat.


This obviously don't hold if you need a power NPN. Just revert to the 3
transistors circuit.

Just making sure you really understood the drops. Of course these
configurations are butt-slow on turn-off.
Click to expand...
Now we too are sure you understand this basic stuff.
Well, I think.


--
Thanks,
Fred.
 
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