Hi

Fishing for ideas...
I want to design a cirquit to drive a few (preliminary 4) DCmotors back and=
 forvard.  The original design used relays and no motor protection, thus=
 motors died...

As cheap as possible

Motors are 12V, supply is 12V car system
Motor current is rated 8A start, but i will current limit to approx 3A.
Drive time is about one second, then long time rest.

All motors may operate at the same time, but there might be advantageous to=
 drive them one by one: =20
o Less total peak current (smaller system fuse)
o I may use one common current limiter

Extra plus if i can connect it also to 24 volts system.

So I thought that on the input i use a 78S10 or something: simple 10V=
 regulator with suitable current limiting.  (Somebody know of a low-drop=
 2..3A 12V regulator that accept 30V?)

Then i use one simple H-drive for each motor, controlled in sequence by a=
 PIC.

Now, this makes for quite a few transistors if built discrete.
Are there cheap IC H-drives for approx 3A?

I can cheat by connecting one side of all motors together and connect that=
 to either + or minus by a half H, then i only need another half H per=
 motor.  And then i may afford having that common half H as a relay, gaining=
 less voltage drop.

Other ideas?


Manufacture volume is 100+

/Morgan

Morgan Olsson, Morgans Reglerteknik AB
H=E4llek=E5s, 277 35 KIVIK, SWEDEN
info@morgansreglerteknik.se
http://www.morgansreglerteknik.se
tel +46(0)414-446620

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics