Hi guys,
This is a follow-up to this thread:
http://forum.allaboutcircuits.com/showthread.php?t=40653&page=4
It's too old to post to the thread so I'm starting a new one. Page 3 shows the recommend circuit from AudioGuru that I've been using. Quick summary: I used a pair of 5v signals to drive 10 volts to a motor, one to drive forward and one signal to reverse the motor. Motor typically drew 100-200 mA.
Well, for the past year or so I've been using this design and it's done fairly well. But I've had a few circuits fail because of the stalling current burning up the transistors.
So, it's time to update the circuit and make it more robust as well as a few other changes.
Ok, so the 2 main changes: 3.3v control signal operation (was 5v) and bigger transistors. I still have the 10 volt motor voltage. The same motor, but now I need to consider that at stall the motor can draw 400-500 mA for about 5 seconds.
I like surface mount parts. On the darlington pair, I don't mind if it's two different NPN transistors. Cost-sensitive of course.
I've started looking through components. But I'm not an analog designer and thought someone might have the experience to quickly chose some parts. I'm hoping I covered the various pieces... let me know if I missed something.
Thanks as always
Tony
This is a follow-up to this thread:
http://forum.allaboutcircuits.com/showthread.php?t=40653&page=4
It's too old to post to the thread so I'm starting a new one. Page 3 shows the recommend circuit from AudioGuru that I've been using. Quick summary: I used a pair of 5v signals to drive 10 volts to a motor, one to drive forward and one signal to reverse the motor. Motor typically drew 100-200 mA.
Well, for the past year or so I've been using this design and it's done fairly well. But I've had a few circuits fail because of the stalling current burning up the transistors.
So, it's time to update the circuit and make it more robust as well as a few other changes.
Ok, so the 2 main changes: 3.3v control signal operation (was 5v) and bigger transistors. I still have the 10 volt motor voltage. The same motor, but now I need to consider that at stall the motor can draw 400-500 mA for about 5 seconds.
I like surface mount parts. On the darlington pair, I don't mind if it's two different NPN transistors. Cost-sensitive of course.
I've started looking through components. But I'm not an analog designer and thought someone might have the experience to quickly chose some parts. I'm hoping I covered the various pieces... let me know if I missed something.
Thanks as always
Tony