H-Bridge issue

All,
I think if you don't smoke some cheap parts in the begining
you will probably smoke some expensive parts later. I have
built my own H-bridge and after awhile it worked but I eventually
gave in and started using an off the shelf unit. I like the L298N multiwatt
style (from ST Microelectronics) but you have to remember to add good diodes
to squelch the back
emf. I used UC3611N (8 pin dip from TI).
Good luck
Harry
_____

From: b... [mailto:b...] On Behalf Of
r...@aol.com
Sent: Wednesday, May 14, 2008 12:57 PM
To: b...
Subject: Re: [BasicX] Re: H-Bridge issue

Hi,

Hey your are not along. Most of us learned in the way your are going
through. Learning electronics is not so easy as? the people think. Sometime
you have to learned front mistakes. Nobody like it but that's is the only?
way to learn alone.

across each I was going to give you an advice with your project if you one
to try it again. If I were you I add one diode 1N4002mosfet. On the top
mosfet install a diode with the cathode or the band of the the diode to the
drain and the anode to the? source. On the bottom one the diode band should
be on the source and the anode to ground. What you are doing is bypass the
kick back from the motor when you open the mosfet. Because the mosfet you
are using is 60 volts 50 amps. No way the load is killing does mosfet.It is
the voltage front the motor when you open the mosfet.

Good luck

rosarite

-----Original Message-----
From: hmwong76 com>
To: basicx@yahoogroups. com
Sent: Wed, 14 May 2008 9:35 am
Subject: [BasicX] Re: H-Bridge issue

Hi there everyone.

There is a saying, "Knowledge without thinking is useless. Thinking

without knowledge is dangerous". Well, if my memory serves me right

and frankly, I came to agree that saying.

So far, of all my tryouts, the MOSFET Driver TC4469 logic drive is

correct, just a matter of wrong wiring to the high side and low side

MOSFET groups. Nevermind, swallow that failure and end up with dead

TC4469, a 18V diode, an IRFZ44.

Rectify the problem later, when everything seems ok with my trusty

DMM (no shorts due to my amature soldering, voltage drop check,

etc.), together with my 14.4VDC cordless drill motor, it started to

run with no problem but it just would not stop. Meaning, dead IRFZ44

and IRF4905. Found out that 2 possibilities, as mentioned by fellow

forumers in other thread, Gate current too high and also the back EMF

is too high for the internal diode. Hard to swallow but still, life

goes on.

Rectify the problem (again), DMM voltage poking seems everything

performs nicely. Start to provide signal, a small popping sound was

heard. Again, a blown IRFZ44 and IRF4905. So bitter, but hey, "Life's

a box of chocolates, ya never know what ya gonna get".

Still, my desire to learn the ropes is high. Having said that, is

there still something I missed out or is it that the trade of

matching components has some hidden secrets in which I had not learn

through my mistakes?

There are so many projects available on the net which involves

driving MOSFETs seems to be so simple and with no protection. How

does mine differs so much from others?

Sorry for those who sees this reply as a ranting but I am sure even

some BasicX programmers face many H-Bridge or MOSFET driving issues.

Regards.




Start a New Thread

Hi,

First and foremost, thank you for sticking up. Anyway, as for the
schematic diagram, it can be found in the BasicX's file section or
you can go to

http://f1.grp.yahoofs.com/v1/
0DMsSIi2OrZflQ47CT5P194cWaRZ8wh7Jf_6xt1msDP3rtaTXVD7N1331di8DnDnzQtS7_GHoVJITh3KT-
s3gJTyUnQ5/Sketches/schematic.GIF

Thanks.

Regards.
--- In b..., "Don LeRoi" wrote:
>
> HM,
>
> Can you post the schematic?
>
> - Don
>

Start a New Thread

Hi there Harry. Thanks for the advice and appreciate that. That's a
wise thought you got there. Glad you can share your view on that. The
L298N seems similar to the previous suggested LMD18200. As mentioned
earlier, I wish to learn the ropes. I would give it a few more tries
and if that day comes, will go for the off the shelf units. Thanks.

Regards.

--- In b..., "Harry J. White" wrote:
>
> All,
> I think if you don't smoke some cheap parts in the begining
> you will probably smoke some expensive parts later. I have
> built my own H-bridge and after awhile it worked but I eventually
> gave in and started using an off the shelf unit. I like the L298N
multiwatt
> style (from ST Microelectronics) but you have to remember to add
good diodes
> to squelch the back
> emf. I used UC3611N (8 pin dip from TI).
> Good luck
> Harry
> _____
>
> From: b... [mailto:b...] On
Behalf Of
> rosarite@...
> Sent: Wednesday, May 14, 2008 12:57 PM
> To: b...
> Subject: Re: [BasicX] Re: H-Bridge issue
> Hi,
>
> Hey your are not along. Most of us learned in the way your are going
> through. Learning electronics is not so easy as? the people think.
Sometime
> you have to learned front mistakes. Nobody like it but that's is
the only?
> way to learn alone.
>
> across each I was going to give you an advice with your project if
you one
> to try it again. If I were you I add one diode 1N4002mosfet. On the
top
> mosfet install a diode with the cathode or the band of the the
diode to the
> drain and the anode to the? source. On the bottom one the diode
band should
> be on the source and the anode to ground. What you are doing is
bypass the
> kick back from the motor when you open the mosfet. Because the
mosfet you
> are using is 60 volts 50 amps. No way the load is killing does
mosfet.It is
> the voltage front the motor when you open the mosfet.
>
> Good luck
>
> rosarite
>
> -----Original Message-----
> From: hmwong76 com>
> To: basicx@yahoogroups. com
> Sent: Wed, 14 May 2008 9:35 am
> Subject: [BasicX] Re: H-Bridge issue
>
> Hi there everyone.
>
> There is a saying, "Knowledge without thinking is useless. Thinking
>
> without knowledge is dangerous". Well, if my memory serves me right
>
> and frankly, I came to agree that saying.
>
> So far, of all my tryouts, the MOSFET Driver TC4469 logic drive is
>
> correct, just a matter of wrong wiring to the high side and low
side
>
> MOSFET groups. Nevermind, swallow that failure and end up with dead
>
> TC4469, a 18V diode, an IRFZ44.
>
> Rectify the problem later, when everything seems ok with my trusty
>
> DMM (no shorts due to my amature soldering, voltage drop check,
>
> etc.), together with my 14.4VDC cordless drill motor, it started to
>
> run with no problem but it just would not stop. Meaning, dead
IRFZ44
>
> and IRF4905. Found out that 2 possibilities, as mentioned by fellow
>
> forumers in other thread, Gate current too high and also the back
EMF
>
> is too high for the internal diode. Hard to swallow but still, life
>
> goes on.
>
> Rectify the problem (again), DMM voltage poking seems everything
>
> performs nicely. Start to provide signal, a small popping sound was
>
> heard. Again, a blown IRFZ44 and IRF4905. So bitter, but hey,
"Life's
>
> a box of chocolates, ya never know what ya gonna get".
>
> Still, my desire to learn the ropes is high. Having said that, is
>
> there still something I missed out or is it that the trade of
>
> matching components has some hidden secrets in which I had not
learn
>
> through my mistakes?
>
> There are so many projects available on the net which involves
>
> driving MOSFETs seems to be so simple and with no protection. How
>
> does mine differs so much from others?
>
> Sorry for those who sees this reply as a ranting but I am sure even
>
> some BasicX programmers face many H-Bridge or MOSFET driving issues.
>
> Regards.
>
>
>
>
>
>
>

Start a New Thread

Hi,

Regarding the .gif schematic, there are serious errors in the symbols and part
number labeling of the power MOSFETs. Please refer to the IR spec sheets
and the way H-Bridge circuits are wired. Google "H-bridge".

Best regards, Eric

----- Original Message -----
From: hmwong76
To: b...
Sent: Thursday, May 15, 2008 6:18 AM
Subject: [BasicX] Re: H-Bridge issue
Hi,

First and foremost, thank you for sticking up. Anyway, as for the
schematic diagram, it can be found in the BasicX's file section or
you can go to

http://f1.grp.yahoofs.com/v1/
0DMsSIi2OrZflQ47CT5P194cWaRZ8wh7Jf_6xt1msDP3rtaTXVD7N1331di8DnDnzQtS7_GHoVJITh3KT-
s3gJTyUnQ5/Sketches/schematic.GIF

Thanks.

Regards.

--- In b..., "Don LeRoi" wrote:
>
> HM,
>
> Can you post the schematic?
>
> - Don
>


Start a New Thread

HM,

As I said before, I use the LMD18200 for these circuits, so I'm not
very familiar with the discrete H-bridge circuits. However, I believe
that your circuit requires a low to turn on the p-channel mosfets and a
high to turn on the n-channel mosfets. The way you have the TC4469
wired appears to turn on the mosfets that are directly in series with
each other, rather than the ones that are on either side of the motor.

I think that pin 13 of the TC4469 should connect to pins 4 and 9 and
pin 12 should connect to pin 6 to get the right logic.

- Don
Start a New Thread

Hi there, sorry for that. Clean up the diagram abit, hope this
version will clear all the confusion. Again as before the link is

http://f1.grp.yahoofs.com/v1/
0BQtSK5Ri5wbxk5bPMDDlwUaSIP4DDzcAnL8J_4sb0KJQ9zd8Hl-
pTp_bT0h0B52NZw5De5FMFHCCBqIC78f86GC6Nt4/Sketches/schematic.GIF

Regards.

--- In b..., "eserdahl@" wrote:
>
> Hi,
>
> Regarding the .gif schematic, there are serious errors in the
symbols and part
> number labeling of the power MOSFETs. Please refer to the IR spec
sheets
> and the way H-Bridge circuits are wired. Google "H-bridge".
>
> Best regards, Eric
>
> ----- Original Message -----
> From: hmwong76
> To: b...
> Sent: Thursday, May 15, 2008 6:18 AM
> Subject: [BasicX] Re: H-Bridge issue
> Hi,
>
> First and foremost, thank you for sticking up. Anyway, as for the
> schematic diagram, it can be found in the BasicX's file section
or
> you can go to
>
> http://f1.grp.yahoofs.com/v1/
>
0DMsSIi2OrZflQ47CT5P194cWaRZ8wh7Jf_6xt1msDP3rtaTXVD7N1331di8DnDnzQtS7_GHoVJITh3KT-
> s3gJTyUnQ5/Sketches/schematic.GIF
>
> Thanks.
>
> Regards.
>
> --- In b..., "Don LeRoi" wrote:
> >
> > HM,
> >
> > Can you post the schematic?
> >
> > - Don
> >
>
>
>

Start a New Thread

HM,

If your schematic is correct, your connections to the TC4469 give the
logic in your truth tables, which I think is wrong. I think what you
want is:

TC4469 Fwd. Rev.

13 1 (Off) 0 (On) Left P-Channel
12 0 (On) 1 (Off) Right P-Channel
11 1 (On) 0 (Off) Left N-Channel
10 0 (Off) 1 (On) Right N-Channel

You have pin 13 connected to pins 4 and 6 and pin 12 connected to pin
9. Connecting pin 13 to pins 4 and 9 and connecting pin 12 to pin 6
should give you the right logic.

- Don
Start a New Thread

Hi Don. The way you put it, you are correct. Seems i
made a silly mistake then. Realizing this flaw, came
another question. I'm running with 24V, wouldn't at
whatever 12 or 0V at the high gate, the P MOSFET
would still be on?

Regards.
--- In b..., "Don LeRoi"
..> wrote:
>
> HM,
>
> As I said before, I use the LMD18200 for these
circuits, so I'm not
> very familiar with the discrete H-bridge circuits.
However, I believe
> that your circuit requires a low to turn on the
p-channel mosfets and a
> high to turn on the n-channel mosfets. The way
you have the TC4469
> wired appears to turn on the mosfets that are
directly in series with
> each other, rather than the ones that are on
either side of the motor.
>
> I think that pin 13 of the TC4469 should connect
to pins 4 and 9 and
> pin 12 should connect to pin 6 to get the right
logic.
>
> - Don
>

Start a New Thread

--- In b..., "hmwong76" wrote:
>
> Hi Don. The way you put it, you are correct. Seems i
> made a silly mistake then. Realizing this flaw, came
> another question. I'm running with 24V, wouldn't at
> whatever 12 or 0V at the high gate, the P MOSFET
> would still be on?
>

HM,

I hadn't noticed that. Yes, the P-channel MOSFETs would always be on.
To run on 24V, you will need to do some level shifting in order to turn
the P-channel devices off.

- Don
Start a New Thread

--- In b..., "hmwong76" wrote:
>
> Hi Don. The way you put it, you are correct. Seems i
> made a silly mistake then. Realizing this flaw, came
> another question. I'm running with 24V, wouldn't at
> whatever 12 or 0V at the high gate, the P MOSFET
> would still be on?
>
> Regards.
HM,

Check out the schematic I put in the files section below yours for a
possible solution.

- Don
Start a New Thread