P-Channel MOSFET
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Posts: 46,084
Do any of you know of a P-Channel compliment or equivalent to the N-Channel
IRL520 MOSFET? This is for a Basic Stamp related project by the way. I'd
like to be able to use logic control on either the negative or positive
side of a load as I need to.
Thanks,
Tim
IRL520 MOSFET? This is for a Basic Stamp related project by the way. I'd
like to be able to use logic control on either the negative or positive
side of a load as I need to.
Thanks,
Tim
Comments
up, or is it completely trial and error? I can't be the only one who could
use advise from the pro's here.
Tim
At 01:02 PM 3/31/2004, you wrote:
>Do any of you know of a P-Channel compliment or equivalent to the N-Channel
>IRL520 MOSFET? This is for a Basic Stamp related project by the way. I'd
>like to be able to use logic control on either the negative or positive
>side of a load as I need to.
>
>Thanks,
>
>Tim
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>Yahoo! Groups Links
>
>
>
>
Otherwise, you will have to look at the characteristics and figure it out
yourself<G>.
Original Message
From: Timothy Medema [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=vRJr7CQofoCObNyJzu0QK4HJh8va3PUD_lm_-4txe-Xgq-1GjTKQwPrT6dfu4UlBicoQuARgd0jEJWnv]timm@c...[/url
Sent: Wednesday, March 31, 2004 4:52 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] P-Channel MOSFET
Better yet, what method can you recommend for looking something like this
up, or is it completely trial and error? I can't be the only one who could
use advise from the pro's here.
Tim
At 01:02 PM 3/31/2004, you wrote:
>Do any of you know of a P-Channel compliment or equivalent to the
>N-Channel IRL520 MOSFET? This is for a Basic Stamp related project by
>the way. I'd like to be able to use logic control on either the
>negative or positive side of a load as I need to.
>
>Thanks,
>
>Tim
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject
>and
>Body of the message will be ignored.
>
>Yahoo! Groups Links
>
>
>
>
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
Yahoo! Groups Links
>
> [noparse][[/noparse]W]hat method can you recommend for looking something like this
> up, or is it completely trial and error?
Generally, if you search for the device number and the
word "complementary" (note the spelling), you'll find references to a
complementary part. You can also look for a device with similar
parameters. This is more difficult unless you have data in a
convenient form.
I found nothing for this part. It may be because this device is a
logic MOSFET, intended to be gated by a 5V logic signal. (Perhaps
the L in the device number indicates Logic). I haven't thought it
through completely but it may impossible to construct a p-channel
logic MOSFET. All of the IRLxxx parts that I've seen are n-channel.
current you are going to pull through the device
http://www.fairchildsemi.com/ds/FD/FDG316P.pdf
http://www.fairchildsemi.com/ds/FD/FDN336P.pdf
http://www.fairchildsemi.com
ken
===============================
Better yet, what method can you recommend for looking something like this
up, or is it completely trial and error? I can't be the only one who could
use advise from the pro's here.
Tim
[noparse][[/noparse]Non-text portions of this message have been removed]
Logic level P-Ch MOSFETs aren't quite as useful as the N-ch variety if your
load voltage is greater than 5 volts, as is often the case...
First, let's consider the common N-Ch setup with a device like the IRL520N.
The MOSFET is switching on the ground side of the load, with the "source"
connected to ground, the "drain" connected to the load, and the "gate"
connected to the Stamp I/O pin. The positive supply voltage is connected to
the other side of the load. The MOSFET is off when the gate voltage is at
the same level as the source. That would be when the Stamp pin is driven
low in this case. When the Stamp pin is driven high, the gate is now 5
volts more positive than the source, and the MOSFET is turned on. Note that
it doesn't matter if the load's power supply voltage is 5V, 12V, 30V,
tc. -- the gate will still be either at 0 volts or +5 volts relative to the
source, which is good.
Now let's take a look at a typical P-Ch connection, which would be the
equivalent of using a PNP transistor to switch on the positive side of the
load. The MOSFET will be connected between the B+ supply and the "top" side
of the load, with the other side of the load connected to ground. Let's say
we're using a +12V supply for the load...
Think of this as a mirror image of the N-Ch arrangement. The P-Ch MOSFET's
source is connected to +12V, and its gate must be at the same voltage level
as the source to turn it off, or must be brought more negative (toward
ground) to turn it on. So the gate must be at +12 volts to keep the MOSFET
off. If you connect the gate directly to the Stamp I/O pin, the gate
voltage will be at +5 volts with the Stamp pin high, and at 0 volts with the
Stamp pin low. Either way, the MOSFET will remain on since the gate will be
7 volts more negative than the source when the Stamp pin is high, or 12
volts more negative than the source when the Stamp pin is low. Remember
this is an "upside down" mirror image of the N-Ch arrangement.
An easy way to deal with this dilemma is to use a NPN transistor such as a
2N3904 connected to the Stamp I/O pin as a level translator. The emitter
would be grounded, the base connected to the I/O pin through a ~10k series
resistor, and the collector would be connected to the P-ch MOSFET gate. A
pull-up resistor (10k is fine) would also need to be connected between the
MOSFET's gate and source. The resistor values could be increased or
decreased depending on how "hard/fast" you needed to switch the MOSFET. For
slow switching, it isn't critical. If you're doing high frequency PWM, it's
a very different story.
With the Stamp I/O pin low, the NPN is off, so the pull-up resistor pulls
the MOSFET gate up to B+, turning it off. When the Stamp I/O pin is driven
high, current flows through the NPN base, turning it on. That pulls the
MOSFET gate to ground, turning it on. In this configuration, there is no
advantage to using a logic level P-Ch MOSFET. If you're using a +5V supply
to the load, then the logic level P-Ch would be fine with the gate connected
directly to the Stamp pin. But it's only a matter of a few pennies for the
2N3904 (or any small NPN) and the two resistors.
...So that's why I stock the P-Ch IRF9530N, which is not logic level, but is
a good complement to the IRL520 and IRL530. (100V max, with similar on
resistance and current ratings.) [noparse]:o[/noparse])
-Randy
www.glitchbuster.com
Original Message
From: "Timothy Medema" <timm@c...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, March 31, 2004 1:02 PM
Subject: [noparse][[/noparse]basicstamps] P-Channel MOSFET
>
> Do any of you know of a P-Channel compliment or equivalent to the
N-Channel
> IRL520 MOSFET? This is for a Basic Stamp related project by the way. I'd
> like to be able to use logic control on either the negative or positive
> side of a load as I need to.
>
> Thanks,
>
> Tim
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
> Yahoo! Groups Links
>
>
>
>
>
wrote:
> Hi Tim,
>
> Logic level P-Ch MOSFETs aren't quite as useful as the N-ch variety
if your
> load voltage is greater than 5 volts, as is often the case...
>
> First, let's consider the common N-Ch setup with a device like the
IRL520N.
> The MOSFET is switching on the ground side of the load, with
the "source"
> connected to ground, the "drain" connected to the load, and
the "gate"
> connected to the Stamp I/O pin. The positive supply voltage is
connected to
> the other side of the load. The MOSFET is off when the gate
voltage is at
> the same level as the source. That would be when the Stamp pin is
driven
> low in this case. When the Stamp pin is driven high, the gate is
now 5
> volts more positive than the source, and the MOSFET is turned on.
Note that
> it doesn't matter if the load's power supply voltage is 5V, 12V,
30V,
> tc. -- the gate will still be either at 0 volts or +5 volts
relative to the
> source, which is good.
>
> Now let's take a look at a typical P-Ch connection, which would be
the
> equivalent of using a PNP transistor to switch on the positive side
of the
> load. The MOSFET will be connected between the B+ supply and
the "top" side
> of the load, with the other side of the load connected to ground.
Let's say
> we're using a +12V supply for the load...
>
> Think of this as a mirror image of the N-Ch arrangement. The P-Ch
MOSFET's
> source is connected to +12V, and its gate must be at the same
voltage level
> as the source to turn it off, or must be brought more negative
(toward
> ground) to turn it on. So the gate must be at +12 volts to keep
the MOSFET
> off. If you connect the gate directly to the Stamp I/O pin, the
gate
> voltage will be at +5 volts with the Stamp pin high, and at 0 volts
with the
> Stamp pin low. Either way, the MOSFET will remain on since the
gate will be
> 7 volts more negative than the source when the Stamp pin is high,
or 12
> volts more negative than the source when the Stamp pin is low.
Remember
> this is an "upside down" mirror image of the N-Ch arrangement.
>
> An easy way to deal with this dilemma is to use a NPN transistor
such as a
> 2N3904 connected to the Stamp I/O pin as a level translator. The
emitter
> would be grounded, the base connected to the I/O pin through a ~10k
series
> resistor, and the collector would be connected to the P-ch MOSFET
gate. A
> pull-up resistor (10k is fine) would also need to be connected
between the
> MOSFET's gate and source. The resistor values could be increased or
> decreased depending on how "hard/fast" you needed to switch the
MOSFET. For
> slow switching, it isn't critical. If you're doing high frequency
PWM, it's
> a very different story.
>
> With the Stamp I/O pin low, the NPN is off, so the pull-up resistor
pulls
> the MOSFET gate up to B+, turning it off. When the Stamp I/O pin
is driven
> high, current flows through the NPN base, turning it on. That
pulls the
> MOSFET gate to ground, turning it on. In this configuration, there
is no
> advantage to using a logic level P-Ch MOSFET. If you're using a
+5V supply
> to the load, then the logic level P-Ch would be fine with the gate
connected
> directly to the Stamp pin. But it's only a matter of a few pennies
for the
> 2N3904 (or any small NPN) and the two resistors.
>
> ...So that's why I stock the P-Ch IRF9530N, which is not logic
level, but is
> a good complement to the IRL520 and IRL530. (100V max, with
similar on
> resistance and current ratings.) [noparse]:o[/noparse])
>
> -Randy
> www.glitchbuster.com
>
>
Interesting take and good application.
Logic Level MOSFETS are probably much easier to use than trying to
use mosfet drivers.
Also, it is possible to bootstrap the signal to an NPN device to use
them in place of a PNP. That makes it simiplier to have one unit for
both but it does complicate the circuit.
Dave
Thank You! I now understand MOSFET's better than I have before. You have
explained complete examples here and that learning method works so well for
me. Also, I'll be able to refer back to your examples if my memory fails
me, should a little time pass until the next time. I really appreciate
your time invested and I'm surely not the only one to benefit from it
within our group.
Tim
At 12:30 AM 4/1/2004, you wrote:
>Hi Tim,
>
>Logic level P-Ch MOSFETs aren't quite as useful as the N-ch variety if your
>load voltage is greater than 5 volts, as is often the case...
>
>First, let's consider the common N-Ch setup with a device like the IRL520N.
>The MOSFET is switching on the ground side of the load, with the "source"
>connected to ground, the "drain" connected to the load, and the "gate"
>connected to the Stamp I/O pin. The positive supply voltage is connected to
>the other side of the load. The MOSFET is off when the gate voltage is at
>the same level as the source. That would be when the Stamp pin is driven
>low in this case. When the Stamp pin is driven high, the gate is now 5
>volts more positive than the source, and the MOSFET is turned on. Note that
>it doesn't matter if the load's power supply voltage is 5V, 12V, 30V,
>tc. -- the gate will still be either at 0 volts or +5 volts relative to the
>source, which is good.
>
>Now let's take a look at a typical P-Ch connection, which would be the
>equivalent of using a PNP transistor to switch on the positive side of the
>load. The MOSFET will be connected between the B+ supply and the "top" side
>of the load, with the other side of the load connected to ground. Let's say
>we're using a +12V supply for the load...
>
>Think of this as a mirror image of the N-Ch arrangement. The P-Ch MOSFET's
>source is connected to +12V, and its gate must be at the same voltage level
>as the source to turn it off, or must be brought more negative (toward
>ground) to turn it on. So the gate must be at +12 volts to keep the MOSFET
>off. If you connect the gate directly to the Stamp I/O pin, the gate
>voltage will be at +5 volts with the Stamp pin high, and at 0 volts with the
>Stamp pin low. Either way, the MOSFET will remain on since the gate will be
>7 volts more negative than the source when the Stamp pin is high, or 12
>volts more negative than the source when the Stamp pin is low. Remember
>this is an "upside down" mirror image of the N-Ch arrangement.
>
>An easy way to deal with this dilemma is to use a NPN transistor such as a
>2N3904 connected to the Stamp I/O pin as a level translator. The emitter
>would be grounded, the base connected to the I/O pin through a ~10k series
>resistor, and the collector would be connected to the P-ch MOSFET gate. A
>pull-up resistor (10k is fine) would also need to be connected between the
>MOSFET's gate and source. The resistor values could be increased or
>decreased depending on how "hard/fast" you needed to switch the MOSFET. For
>slow switching, it isn't critical. If you're doing high frequency PWM, it's
>a very different story.
>
>With the Stamp I/O pin low, the NPN is off, so the pull-up resistor pulls
>the MOSFET gate up to B+, turning it off. When the Stamp I/O pin is driven
>high, current flows through the NPN base, turning it on. That pulls the
>MOSFET gate to ground, turning it on. In this configuration, there is no
>advantage to using a logic level P-Ch MOSFET. If you're using a +5V supply
>to the load, then the logic level P-Ch would be fine with the gate connected
>directly to the Stamp pin. But it's only a matter of a few pennies for the
>2N3904 (or any small NPN) and the two resistors.
>
>...So that's why I stock the P-Ch IRF9530N, which is not logic level, but is
>a good complement to the IRL520 and IRL530. (100V max, with similar on
>resistance and current ratings.) [noparse]:o[/noparse])
>
>-Randy
>www.glitchbuster.com
>
>
>
>
Original Message
>From: "Timothy Medema" <timm@c...>
>To: <basicstamps@yahoogroups.com>
>Sent: Wednesday, March 31, 2004 1:02 PM
>Subject: [noparse][[/noparse]basicstamps] P-Channel MOSFET
>
>
> >
> > Do any of you know of a P-Channel compliment or equivalent to the
>N-Channel
> > IRL520 MOSFET? This is for a Basic Stamp related project by the way. I'd
> > like to be able to use logic control on either the negative or positive
> > side of a load as I need to.
> >
> > Thanks,
> >
> > Tim
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>Yahoo! Groups Links
>
>
>
>
It is clear to me that I have to make more time to study! I enjoy
electronics very much, but I'm one of those people that the subject doesn't
come very easily to.
Tim
At 05:00 AM 4/1/2004, you wrote:
>--- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
>wrote:
> > Hi Tim,
> >
> > Logic level P-Ch MOSFETs aren't quite as useful as the N-ch variety
>if your
> > load voltage is greater than 5 volts, as is often the case...
> >
> > First, let's consider the common N-Ch setup with a device like the
>IRL520N.
> > The MOSFET is switching on the ground side of the load, with
>the "source"
> > connected to ground, the "drain" connected to the load, and
>the "gate"
> > connected to the Stamp I/O pin. The positive supply voltage is
>connected to
> > the other side of the load. The MOSFET is off when the gate
>voltage is at
> > the same level as the source. That would be when the Stamp pin is
>driven
> > low in this case. When the Stamp pin is driven high, the gate is
>now 5
> > volts more positive than the source, and the MOSFET is turned on.
>Note that
> > it doesn't matter if the load's power supply voltage is 5V, 12V,
>30V,
> > tc. -- the gate will still be either at 0 volts or +5 volts
>relative to the
> > source, which is good.
> >
> > Now let's take a look at a typical P-Ch connection, which would be
>the
> > equivalent of using a PNP transistor to switch on the positive side
>of the
> > load. The MOSFET will be connected between the B+ supply and
>the "top" side
> > of the load, with the other side of the load connected to ground.
>Let's say
> > we're using a +12V supply for the load...
> >
> > Think of this as a mirror image of the N-Ch arrangement. The P-Ch
>MOSFET's
> > source is connected to +12V, and its gate must be at the same
>voltage level
> > as the source to turn it off, or must be brought more negative
>(toward
> > ground) to turn it on. So the gate must be at +12 volts to keep
>the MOSFET
> > off. If you connect the gate directly to the Stamp I/O pin, the
>gate
> > voltage will be at +5 volts with the Stamp pin high, and at 0 volts
>with the
> > Stamp pin low. Either way, the MOSFET will remain on since the
>gate will be
> > 7 volts more negative than the source when the Stamp pin is high,
>or 12
> > volts more negative than the source when the Stamp pin is low.
>Remember
> > this is an "upside down" mirror image of the N-Ch arrangement.
> >
> > An easy way to deal with this dilemma is to use a NPN transistor
>such as a
> > 2N3904 connected to the Stamp I/O pin as a level translator. The
>emitter
> > would be grounded, the base connected to the I/O pin through a ~10k
>series
> > resistor, and the collector would be connected to the P-ch MOSFET
>gate. A
> > pull-up resistor (10k is fine) would also need to be connected
>between the
> > MOSFET's gate and source. The resistor values could be increased or
> > decreased depending on how "hard/fast" you needed to switch the
>MOSFET. For
> > slow switching, it isn't critical. If you're doing high frequency
>PWM, it's
> > a very different story.
> >
> > With the Stamp I/O pin low, the NPN is off, so the pull-up resistor
>pulls
> > the MOSFET gate up to B+, turning it off. When the Stamp I/O pin
>is driven
> > high, current flows through the NPN base, turning it on. That
>pulls the
> > MOSFET gate to ground, turning it on. In this configuration, there
>is no
> > advantage to using a logic level P-Ch MOSFET. If you're using a
>+5V supply
> > to the load, then the logic level P-Ch would be fine with the gate
>connected
> > directly to the Stamp pin. But it's only a matter of a few pennies
>for the
> > 2N3904 (or any small NPN) and the two resistors.
> >
> > ...So that's why I stock the P-Ch IRF9530N, which is not logic
>level, but is
> > a good complement to the IRL520 and IRL530. (100V max, with
>similar on
> > resistance and current ratings.) [noparse]:o[/noparse])
> >
> > -Randy
> > www.glitchbuster.com
> >
> >
>
>Interesting take and good application.
>
>Logic Level MOSFETS are probably much easier to use than trying to
>use mosfet drivers.
>
>Also, it is possible to bootstrap the signal to an NPN device to use
>them in place of a PNP. That makes it simiplier to have one unit for
>both but it does complicate the circuit.
>
>Dave
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>Yahoo! Groups Links
>
>
>
>
Thank you for your help with the search criteria. I often find this to be
a time consuming and frustrating part of a project. I had done a similar
search and found nothing as well.... I hoped that I had missed something or
that someone had a neat technique to hear about.
Tim
At 02:25 PM 3/31/2004, you wrote:
>--- In basicstamps@yahoogroups.com, Timothy Medema <timm@c...> wrote:
> >
> > [noparse][[/noparse]W]hat method can you recommend for looking something like this
> > up, or is it completely trial and error?
>
>Generally, if you search for the device number and the
>word "complementary" (note the spelling), you'll find references to a
>complementary part. You can also look for a device with similar
>parameters. This is more difficult unless you have data in a
>convenient form.
>
>I found nothing for this part. It may be because this device is a
>logic MOSFET, intended to be gated by a 5V logic signal. (Perhaps
>the L in the device number indicates Logic). I haven't thought it
>through completely but it may impossible to construct a p-channel
>logic MOSFET. All of the IRLxxx parts that I've seen are n-channel.
>
>
>
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>Yahoo! Groups Links
>
>
>
>
===================================
Hi Randy,
Thank You! I now understand MOSFET's better than I have before. You have
explained complete examples here and that learning method works so well for
me. Also, I'll be able to refer back to your examples if my memory fails
me, should a little time pass until the next time. I really appreciate
your time invested and I'm surely not the only one to benefit from it
within our group.
Tim
[noparse][[/noparse]Non-text portions of this message have been removed]