5A H-Bridge motor controllers

[karookann]

It also provides some safety features.
W1 and W2 and the inputs the logic circuit, the state of the power transistors are the outputs. Using a logic circuit to control the power transistors allows the circuit to turn on/off only selected pairs of power transistors.
Ie
Forward Q5 = 0, Q6 = 1, Q7 = 1, Q8 = 0
Reverse Q5 = 1, Q6 = 0, Q7 = 0, Q8 = 1
etc etc.

There are no combination of inputs that will allow say Q5 and Q6 to both be on simultaneously. That would cause a short between the positive and negative terminals of the power source. Which as im sure you can imagine would be baddd

I agree! that's also very important.

I think you are right about the safety, this circuit does provide safety feature. But it seems to me that our only task is to keep only one transistor "on" at a time, from Q5 and Q6, and I wonder "isn't it possible to accomplish that with BJT inverters etc".
I meant to say that I agree that it provides safety as well as control, but I think the same task could be done with a little less elements.
Thanks

[ikalogic]

I meant to say that I agree that it provides safety as well as control, but I think the same task could be done with a little less elements.
Thanks

Great! show me, i would love to see it

[karookann]

I think you are right about it, I was only thinking about forward/reverse state of the motor only and I neglected the breaking, disconnected feature.
Thanks for your reply!!!!!!!!

[karookann]

I am still thinking of eliminating these two ICs by appropriate code in my MC, as I have plenty of i/o pins available and enough room for code too. So I would like to have your opinion in this regard.
Furthermore I want to know the purpose of transisters Q1-Q4. I suspect these are for power or voltage issues but I want your expert opinion.

[ikalogic]

I am still thinking of eliminating these two ICs by appropriate code in my MC, as I have plenty of i/o pins available and enough room for code too. So I would like to have your opinion in this regard.
Furthermore I want to know the purpose of transisters Q1-Q4. I suspect these are for power or voltage issues but I want your expert opinion.

Hello,

Sure, if you have spare I/O pins, then you can get rid of those ICs.

The transistors Q1 to Q4 are very important, because they provide high enough base current for the TIP transistors. the I/O from logic gates or from the µC do not give enough current.

[karookann]

Now I completely know the purpose of each component, thanks you very much.

[kenny6]

I have built a h bridge with these tip transistors and controlling them through an Ardunio and i have biased the bases with 330 ohm resistors.This works ok on 6 volts but i cant work out why when i try to run it on 12 volts the transistors start to fry bad immediatly.Yet when i try to biase the bases with 1000 ohm resistors the thing wont even turn on,yet i think the qs get very hot still.I have tied bases together on each side.I am using small mabuchi motors.
Im aware that motors resistance influences collector current
I have calculated that the ideal resistor i should use is about 2000 ohms.if the motors resistance is about 10 ohms.mabuchi motors at 6 volts divides by full load current gives around this value for motor resistance.(6/.560).
My questions are.
What motors are you running on your bridge.2683
Any sugestions to make improvements thanks
back again .I am now using motors by solarbotics and have much better results.I believe these motors draw less current than the Mabuchis.I have a couple of ideas to tinker with when i get time.

[onibnasir]

I made the circuit on breadboard but it is not working. I want to ask one thing. We have to take the output from the collector terminals of the TIP transistors2683 Please respond quickly



i don't understand the question2683

also, you say it's not working, what is the problem exactly2683

[onibnasir]

I made the circuit on breadboard but it is not working. I want to ask one thing. We have to take the output from the collector terminals of the TIP transistors2683 Please respond quickly



i don't understand the question2683

also, you say it's not working, what is the problem exactly2683

The problem is that the potential difference that I am getting at the collector is 0.5 to 0.6 V ....

[WesleyRoss]

I plan to use your circuit to move a 100lb sliding steel door. No micro or pwm. Just 24v. My only concern is driving the TIP's. You mentioned in previous posts, you used 10-25 VDC. Do you see any problem keeping all resistors the same, but using 24vDC2685 Thanks to all for their insight and knowledge. Schematic attached.

[gojko_sisa]

Salam,

I am currently building a Line following robot, and I want to use this H-bridge for the engine control. I have downloaded this PCB schematic, but I I can't figure out what are the inputs P3, P4, P5 for26852685
I have already found what you previously said on this forum:

[/quote]
P4 = 12V / 24V
P5 = 5V
P6 = Ground
[/quote]

Studying this schematic; however, I have found a few issues. In my opinion this inputs should be connected in this way:

P1 - pin 1
P2- pin 4
P3- (+12v)
P4-GND
P5-PWM input
P6-(+5v)
p7-(+FAN)
P8-(-FAN)

Can you double-check yours schematic 2685
Thnx

[Junior]

Hi I'm new in this so i would you ask that the names of the diodes are need for 5A H-Bridge motor controllers and can that works without diodes.
Thanks !

[ikalogic]

Hi I'm new in this so i would you ask that the names of the diodes are need for 5A H-Bridge motor controllers and can that works without diodes.
Thanks !

there MUST be diodes!

any rectifier diodes will do just fine, (but they should have a forward current of 5 to 10 A

[Junior]

ok thanks

[yawstick]

I've tried to download your zip file and getting errors when I try to open it... seems to be corrupted... nice article otherwise.