>On Sep 19, 8:47�pm, Tim Wescott <t...@seemywebsite.com> wrote:
>
>> > I thought it was just me - almost all the parts I want are no stock
>> > everywhere...
>>
>> If employers are afraid to hire even as the work picks up, I see no
>> reason that manufacturers wouldn't be afraid to stock parts, even as
>> demand picks up.
>>
>> Perhaps the "jobless recovery" is a "partless recovery" as well.
>
>We have a serious problem with this at my day job - most of the big
>guys are giving us random leadtimes. I think the recovery is uncertain
>enough that it isn't a sure thing that it's going to be worthwhile to
>fire up a new shift or bring a spare fab online or whatever it is -
>the mfrs just don't want to sign up for increased fixed costs.
>
>On a related note, I found a device that has exactly the inputs I was
>expecting - National LMD18200. Seems like a very old part though.
There are some other like the LMD18200 (approx. 40V/3Apk) chips
aviable
Freescale MC33186
ST: L6203
Infineon TLE7209, TLE5205
all are more or less aviable @ digikey (Austria)
hth
-
Michael Wieser
--
Reply by Noodnik●September 21, 20102010-09-21
"larwe" <zwsdotcom@gmail.com> wrote in message
news:35ebc821-5667-422c-be1c-7b308b497b36@m1g2000vbh.googlegroups.com...
On Sep 19, 4:22 pm, Dave Nadler <d...@nadler.com> wrote:
> > I'm looking for a simple, preferably through-hole H-bridge IC, nothing
> > fancy, for PWM-controlled DC motor drive. (5A max would be plenty).
>
> Sorry if I'm being dense Lewin, but this part is for
> driving a DC motor in one or the other direction,
> for example car electric window.
I need to drive a DC gearhead motor forward and reverse, with some
speed control (2 or 3 steps in each direction). Fine control of motor
speed is not necessary, and this is open loop. It would be a low
frequency PWM signal, but the switching times mentioned in that
specific datasheet seem to imply up to maybe 30kHz is theoretically
doable. Control is from a general-purpose micro with two 10-bit PWM
outputs and various available GPIOs.
I could do what I want to do with discrete FETs but I don't want to
have to design all the shoot-through protection, etc. etc. and worry
about what I might have forgotten - much rather get a canned part.
If shoot-through is what I think it is - both ends of a half bridge being on
together during a transition and shorting the supply - then there are plenty
of half bridge drivers that look after that. Just connect to a pair of
N-channel fets and drive with logic signals (typically H/L and enable). 2
should produce an H-bridge unless I'm missing something.
I've driven FETs up to > 350 KHz using these with no problems.
> PS: careful on lead time of H-bridges - I'm having
> difficulty finding what we need that's actually
I thought it was just me - almost all the parts I want are no stock
everywhere...
Reply by larwe●September 20, 20102010-09-20
On Sep 20, 4:28=A0pm, Anton Erasmus <nob...@spam.prevent.net> wrote:
> >expecting - National LMD18200. Seems like a very old part though.
>
> The even older L298N might also be viable. Stil available from
> multiple sources. In stock at Digikey.
Cheap, too. But dropping 10W(ish) in the chip for a 2A load?! :)
Reply by Tim Wescott●September 20, 20102010-09-20
On 09/20/2010 01:28 PM, Anton Erasmus wrote:
> On Sun, 19 Sep 2010 17:52:46 -0700 (PDT), larwe<zwsdotcom@gmail.com>
> wrote:
>
>> On Sep 19, 8:47 pm, Tim Wescott<t...@seemywebsite.com> wrote:
>>
>>>> I thought it was just me - almost all the parts I want are no stock
>>>> everywhere...
>>>
>>> If employers are afraid to hire even as the work picks up, I see no
>>> reason that manufacturers wouldn't be afraid to stock parts, even as
>>> demand picks up.
>>>
>>> Perhaps the "jobless recovery" is a "partless recovery" as well.
>>
>> We have a serious problem with this at my day job - most of the big
>> guys are giving us random leadtimes. I think the recovery is uncertain
>> enough that it isn't a sure thing that it's going to be worthwhile to
>> fire up a new shift or bring a spare fab online or whatever it is -
>> the mfrs just don't want to sign up for increased fixed costs.
>>
>> On a related note, I found a device that has exactly the inputs I was
>> expecting - National LMD18200. Seems like a very old part though.
>
> The even older L298N might also be viable. Stil available from
> multiple sources. In stock at Digikey.
> 60000 stock at Future Electronics.
>
> Regards
> Anton Erasmus
Lovely part. Huge voltage drop compared to a MOSFET H-bridge.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by Anton Erasmus●September 20, 20102010-09-20
>On Sep 19, 8:47�pm, Tim Wescott <t...@seemywebsite.com> wrote:
>
>> > I thought it was just me - almost all the parts I want are no stock
>> > everywhere...
>>
>> If employers are afraid to hire even as the work picks up, I see no
>> reason that manufacturers wouldn't be afraid to stock parts, even as
>> demand picks up.
>>
>> Perhaps the "jobless recovery" is a "partless recovery" as well.
>
>We have a serious problem with this at my day job - most of the big
>guys are giving us random leadtimes. I think the recovery is uncertain
>enough that it isn't a sure thing that it's going to be worthwhile to
>fire up a new shift or bring a spare fab online or whatever it is -
>the mfrs just don't want to sign up for increased fixed costs.
>
>On a related note, I found a device that has exactly the inputs I was
>expecting - National LMD18200. Seems like a very old part though.
The even older L298N might also be viable. Stil available from
multiple sources. In stock at Digikey.
60000 stock at Future Electronics.
Regards
Anton Erasmus
Reply by Mark Borgerson●September 20, 20102010-09-20
In article <9c51d5b3-ef28-4ea7-bfa2-5c8c0b981255
@k13g2000vbq.googlegroups.com>, zwsdotcom@gmail.com says...
> On Sep 19, 8:47=A0pm, Tim Wescott <t...@seemywebsite.com> wrote:
>=20
> > > I thought it was just me - almost all the parts I want are no stock
> > > everywhere...
> >
> > If employers are afraid to hire even as the work picks up, I see no
> > reason that manufacturers wouldn't be afraid to stock parts, even as
> > demand picks up.
> >
> > Perhaps the "jobless recovery" is a "partless recovery" as well.
>=20
> We have a serious problem with this at my day job - most of the big
> guys are giving us random leadtimes. I think the recovery is uncertain
> enough that it isn't a sure thing that it's going to be worthwhile to
> fire up a new shift or bring a spare fab online or whatever it is -
> the mfrs just don't want to sign up for increased fixed costs.
>=20
> On a related note, I found a device that has exactly the inputs I was
> expecting - National LMD18200. Seems like a very old part though.
>=20
I don't know what you call old----but I have that part in systems
designed in 2003 and it wasn't new when I first came across it. OTOH,
it is still available through DigiKey---although it is currently out of
stock and there won't be more until ~10/15/10.
If you need one for testing and can't find an easy source, I have
a leftover in the miscellaneous parts bin and can mail it to you.
Mark Borgerson
Reply by larwe●September 19, 20102010-09-19
On Sep 19, 8:47=A0pm, Tim Wescott <t...@seemywebsite.com> wrote:
> > I thought it was just me - almost all the parts I want are no stock
> > everywhere...
>
> If employers are afraid to hire even as the work picks up, I see no
> reason that manufacturers wouldn't be afraid to stock parts, even as
> demand picks up.
>
> Perhaps the "jobless recovery" is a "partless recovery" as well.
We have a serious problem with this at my day job - most of the big
guys are giving us random leadtimes. I think the recovery is uncertain
enough that it isn't a sure thing that it's going to be worthwhile to
fire up a new shift or bring a spare fab online or whatever it is -
the mfrs just don't want to sign up for increased fixed costs.
On a related note, I found a device that has exactly the inputs I was
expecting - National LMD18200. Seems like a very old part though.
Reply by Tim Wescott●September 19, 20102010-09-19
On 09/19/2010 05:28 PM, larwe wrote:
> On Sep 19, 4:22 pm, Dave Nadler<d...@nadler.com> wrote:
>
>>> I'm looking for a simple, preferably through-hole H-bridge IC, nothing
>>> fancy, for PWM-controlled DC motor drive. (5A max would be plenty).
>>
>> Sorry if I'm being dense Lewin, but this part is for
>> driving a DC motor in one or the other direction,
>> for example car electric window.
>
> I need to drive a DC gearhead motor forward and reverse, with some
> speed control (2 or 3 steps in each direction). Fine control of motor
> speed is not necessary, and this is open loop. It would be a low
> frequency PWM signal, but the switching times mentioned in that
> specific datasheet seem to imply up to maybe 30kHz is theoretically
> doable. Control is from a general-purpose micro with two 10-bit PWM
> outputs and various available GPIOs.
>
> I could do what I want to do with discrete FETs but I don't want to
> have to design all the shoot-through protection, etc. etc. and worry
> about what I might have forgotten - much rather get a canned part.
>
>> PS: careful on lead time of H-bridges - I'm having
>> difficulty finding what we need that's actually
>
> I thought it was just me - almost all the parts I want are no stock
> everywhere...
If employers are afraid to hire even as the work picks up, I see no
reason that manufacturers wouldn't be afraid to stock parts, even as
demand picks up.
Perhaps the "jobless recovery" is a "partless recovery" as well.
--
Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
Reply by larwe●September 19, 20102010-09-19
On Sep 19, 4:22=A0pm, Dave Nadler <d...@nadler.com> wrote:
> > I'm looking for a simple, preferably through-hole H-bridge IC, nothing
> > fancy, for PWM-controlled DC motor drive. (5A max would be plenty).
>
> Sorry if I'm being dense Lewin, but this part is for
> driving a DC motor in one or the other direction,
> for example car electric window.
I need to drive a DC gearhead motor forward and reverse, with some
speed control (2 or 3 steps in each direction). Fine control of motor
speed is not necessary, and this is open loop. It would be a low
frequency PWM signal, but the switching times mentioned in that
specific datasheet seem to imply up to maybe 30kHz is theoretically
doable. Control is from a general-purpose micro with two 10-bit PWM
outputs and various available GPIOs.
I could do what I want to do with discrete FETs but I don't want to
have to design all the shoot-through protection, etc. etc. and worry
about what I might have forgotten - much rather get a canned part.
> PS: careful on lead time of H-bridges - I'm having
> difficulty finding what we need that's actually
I thought it was just me - almost all the parts I want are no stock
everywhere...
Reply by ●September 19, 20102010-09-19
On 19.09.2010 21:43, larwe wrote:
> I'm looking for a simple, preferably through-hole H-bridge IC, nothing
> fancy, for PWM-controlled DC motor drive. (5A max would be plenty).
> Infineon TLE5205 ought to do the trick, but I don't understand how one
> would drive it.
That may be caused by looking at not entirely the optimal IC for what
you have in mind. I'll second Dave's assessment here: that IC appears
to be intended for simple DC use, not for PWM'ed operation.
The IC you're looking for would effectively need five output states (two
different ones that end up as high-z) and thus _three_ inputs: e.g.
direction, brake (for "00" state) and enable (turn off to reach "zz").
> I was expecting a direction input and a drive input. As it stands, if
> I PWM IN1 and set IN2 according to my desired output direction, I'll
> be PWMing between either free or braking according to whether I'm set
> for reverse or forward direction.
You could PWM both inputs, and thus have
PP:P0 --- PWM forward
P0:0P --- PWM backward