dc motor driver

hi,

i am doing a robotic project . i am using a dc motor which is having high power...i used uln2003 driver ic to connect to the motor.but i found the ic is getting heated....i had shorted 3 pins of ic inorder to get high current capacity.....if any of you know any current sink ic which is having 1-3Amp current capcity....hoping that i will get reply from you...


thanking you
sanoop

hai sanoop

Is it a stepper motor ?
Why are u using darlinton ics ?

I think the correct option is the h-bridge ics
L293 or L298.

L298s are right for the current. Heatsink the 298, about 4"x4"

Heat is going to be your enemy here. You should get a tight handle on the current draw of the motor.

The L293 won't deliver the current you need. the L298 will do it though the limit appears to be 3A - right at your limit. that's a little troublesome. neither package (multiwatt or powerso) are super easy to prototype with. with 3A of current, the L298 will dissipate a very large amount of heat Vsat at 2A is 4.9V - that's 9.8W. Take it up to 3A and it's going to around 15W. I suspect you can get by with passive cooling (heatsink) for 1A draw but 2 or 3A draw will probably need forced air.

alternatively, you could build an h-bridge with mosfets. Mosfets with a reasonably low Rds will give you significantly lower heat dissipation. For example, mosfets with an Rds of .1 ohms will dissipate about a watt each at 3A. It would probably get by with a smallish heatsink. Plenty of plans on the web.

Phil

use L293D for normal DC motors. If it is greater than 600ma go for L298
refer page67 of
MY EXPERIENCE IN AUTONOMOUS ROBOTICS
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