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wise_neha
12-29-2005, 08:39 PM
Hi folks !

I have been using L293D for driving motors with lower current ratings but now I have few heavy motors drawing current more than 2 Amps, so I thought of making a motor driver circuit myself.

Please give me the circuit diagram of a working H-Bridge with part numbers.

addy
12-29-2005, 11:07 PM
jus look in the forum.....
there r a hell lot of h bridge configurations out here.
for the mosfets, i ll suggest u to go for irfz44n.... they can bear gud current.
don forget to use heat sinks for the mosfets.
becoz more than 2amps ll make them really hot.

subot_robot
12-29-2005, 11:31 PM
Hi,
you can also try L298 hbridge ic. each bridge can handle 2A and u can 2 h bridges on the chip in parallel to handle 4A.

Regards
Subot_robot

addy
12-30-2005, 02:12 AM
use parallel connection if ur motor draws max. current not more than 4amps.
hold the shaft wid ur hand try ur best to stop it and check the max. current it draws, this current rating shud be ur basis for choosing the driver.

wise_neha
12-30-2005, 02:21 PM
Could you guys , please explain parallel connection in detail ?

devpriya
12-30-2005, 06:21 PM
Parallel connection means ......umm......let me make it clear with an example

Take ULN2803 , now puttin two channels in parallel means connect those two channels to one output line. So that the output current becomes double of what it could have got from one channel.

Putting two L298 in parallel is also doing the same.....Join to two separate outputs to one input of the motor and do the same with the other end of the motor too. This way you will get twice the current !!!!

Supario
12-30-2005, 10:16 PM
Hi,


jus look in the forum.....
there r a hell lot of h bridge configurations out here.
for the mosfets, i ll suggest u to go for irfz44n.... they can bear gud current.
don forget to use heat sinks for the mosfets.
becoz more than 2amps ll make them really hot.

Do you have to take any extra special precautions while handling these MOSFET devices? Books say that they have a tendency to blow up for no reason in particular so I havent tried using any MOSFETs till now even though I want to build a MOSFET based H Bridge. How much do these irfz44n s cost? Do they have a complimentary p-MOSFET ?

Supario

addy
12-30-2005, 11:35 PM
Books say that they have a tendency to blow up for no reason in particular
blowing up for no reason makes no sense....
anyway, all i said was tat if u r using them for high current applications like more than 2amps, use a heat sink becoz it wont dissipate power tat fast and gets heaated.
irfz44n works pretty well
and its contemporary p type is irf 9530...
i once made a half bridge ussing these two and it workd pretty well for 3.5 amps motor.

prabhanshu
12-31-2005, 12:38 AM
i agree with addy. the mosfets he suggested (i.e. irfz44n) can bear current of anout 40-45amp odd. and actually perform pretty well for this also blowing up for no reason makes no sense ,unless your connections aren't proper.

Supario
12-31-2005, 02:21 PM
Hey,

I meant blowing up because of ESD.

Supario

chinn
07-13-2006, 01:28 PM
Hi
check this out vry nice tutorial

www.mcmanis.com/chuck/robotics/tutorial/h-bridge

cya
chinmay :P

moo
03-18-2007, 01:03 PM
Hi,
When paralleling L298, watchout the pins you need to parallel, otherwise the circuit wont work.It is in the data sheet from st micro. Also mosfets are voltage controlled devices, so you would need Min 10V -12V dc to keep it in saturation and keep heating of mosfets to Min. The gate drive should be 10V( good selection) for irfz44n. The devices cost around Rs 30/- per piece. Try to use a totem pole drive for fast on and off, drive the totempole with 12V DC

ankur1986
02-12-2008, 08:58 AM
Parallel connection means ......umm......let me make it clear with an example

Take ULN2803 , now puttin two channels in parallel means connect those two channels to one output line. So that the output current becomes double of what it could have got from one channel.

Putting two L298 in parallel is also doing the same.....Join to two separate outputs to one input of the motor and do the same with the other end of the motor too. This way you will get twice the current !!!!

Just clear things for me a lil more .
i take 2 ULN2803 . Give 4 inputs thru my parallel port to one of the ULN2803 or both ? also i must connect the power supply to both the IC's right ?

then once all this is done i take o/p 1 of both the IC's and connect it to 1 of d coils of the motor ? and similarly connect rest of the outputs ?