I know people "piggyback" the two ICs, but that didn't work for me (well, I just wired them in parallel on a breadboard). Both chips got warm, but one got significantly hotter than the other. After some research, I found this post, which led me to this datasheet, which said this:
PARALLELING OUTPUTS
Higher output currents can be obtained by paralleling
the outputs of both bridges. For example, the
outputs of an L298N can be connected in parallel to
make a single 3.5 A bridge. To ensure that the current
is fairly divided between the bridges they must
be connected as shown in figure 2. In other words,
channel one should be paralleled with channel four
and channel two paralleled with channel three.
Apart from this rule the connection is very straightforward
the inputs, enables, outputs and emitters
are simply connected together.
The outputs of an L293 or L293E can also be paralleled
in this case too channel 1 must be paralleled
with channel 4 and channel 2 with channel 3.
But if two bridges are needed this is not a good idea
because an L298N may be used. However, if only
Figure 2 : For higher currents outputs can be paralleled.
Take care to parallel channel 1
with channel 4 and channel 2 with channel
This says I have to flip around some of the connections, but it also doesn't mention the l293D, only the l293. Would I use this method for the l293D as well (I am not sure if the extra diode does anything to affect this).
If you look at page 2 of the datasheet you will see that normally a dual motor setup for bidirectional robot motors would be done like this
(illustration to the right of the title "TRUTH TABLE")
The quote you cited is saying that instead of inputs 1 & 7 for motor 1 which is connected to output pins 3 & 6, (with the second motor inputs 15 & 10 for motor 2 on output pins
14 & 11), they are saying that all 4 of the L293 drivers should be configured as a single motor /dual driver setup using input pin 1 jumpered to input pin 15, and input pin 7 jumpered to input pin 10, and the single motor connected across output pins 3-14 jumpered together and 6-11 jumpered together .
Inputs
1,15 (jumpered)
7,10 (jumpered
outputs
3,14 (jumpered)
6,11 (jumpered)
Why ?
I have no idea, but that's what they are saying.
One chip should be used for one motor with twice the current.
If a second motor is needed a second chip is required, configured the same way.
You are getting confused because you found something similar, but not equal to what your were looking for.
What you have found, is suggested to use when you are using a single bidirectional motor.
They are suggesting that setup, so the heat generated, will be more spread across the chip, and can be better dissipated.
Otherwise the heat would be concentrated to a single side of the chip.
But this isn't at all what you're looking for.
You need to know the the 4 center pins aren't just there to offer some connection point for GND level.
They also are there (and at that location) to help heat be dissipated.
You absolutely need to facilitate that, and it looks like that's what you forgot and why the units got (too) hot.
You can stack multiple 293's to each other and connect each pin.
But be sure the center pins 4, 5, 13 and 12 are well connected to a larger copper surface.
Or even connect some kind of heat sink to each of these 8 pins (or whatever number of chips you use times 4).
So trying to do this in a breadboard is not possible? I don't mind soldering them together, but I am assuming I would need thermal paste etc. to keep their temp the same so the transistors inside all work the same amount.
A breadboard is a bad idea if you need heat dissipation in this way.
Using thermal grease sounds like a good idea, and it won't harm if it doesn't actually help.
Try to create a nice large copper surface to be connected to the GND pins.
I am only using one motor, but it is a stepper motor, so would it follow the same principle? (I don't fully understand if that is possible)
Well, if you look at the schematic of a stepper motor how many windings do you see ?
Maybe the fact that you only have one motor shaft has got you confused. Two windings
is the same as two motors for all practical purposes when discussing the topic of your original post (paralleling L293s).
So trying to do this in a breadboard is not possible?
Yes, it is possible, but as I said before, you need two chips, not one, and each needs to be wired as I said (one chip per winding).
If you pay attention to what MAS3 said about the heat dissipation and heat-sinking the GND pins in the center of the chip, MAYBE you can think of a way to do that if you stacked them but your original post suggests that combining sections 1 & 4, 2 & 3, is a better idea than stacking them. The difference is that you can no longer drive two motors from the same chip. You must dedicate one chip to each motor. You should still try to find a way to provide some heatsinking but it should still work on a breadboard without melting it if your motor doesn't draw too much current.
Using an L298 is a smarter way to go because those modules come heatsinked.
Be aware there are 15 different flavors of L298 modules. Look at the photos VERY CAREFULLY and see if you can figure out the difference.
I can treat the stepper as 2 different motors, and use 1 chip per "motor" (so essentially two chips for one stepper). I would wire it by connecting pins 1-4 and 2-3 to allow the chip to spread heat along the whole chip rather than one side of it.
electricviolin:
I would wire it by connecting pins 1-4 and 2-3
Not pins 1 and 4 - you're paralleling channel 1 and channel 4, so you're connecting input 1 and input 4, output 1 and output 4 (not physical pins 1 and 4). Likewise with 2 and 3. You also tie the enable pins together.
Right, okay I see. I am assuming it is two coils, but I will have to check to make sure. If it is 4 wires, it has to be 2 coils, right? 2 coils (2 wires each). Is this for certain or should I check this somehow?
The problem is that you need to understand how the component works, at least for a bit.
This is why i have a large aversion to sites like instructables.
Over there they tell you "Do this and that, to create the world domination device", but they don't tell you what's going on inside that device.
If you roughly understand the component, you can find mistakes in explanations yourself.
And i'm certainly not stating that anyone actually has made such mistake.
Make distinction between words input, output and pin number.
I can see where you saw what you mentioned, and what went wrong if i take the above in consideration.
I can also understand that all the information, which isn't all synchronised might be somewhat overwhelming.
So help yourself and find a schematic of the internal function blocks of that chip you understand and or like the best, and print it as large as you can.
Keep that available when reading the tips given here and check the answers against that print.
That might help.
Look at the schematic of a discrete H-Bridge: H-bridge
Essentially, what you are doing is taking a duplicate of the above H-bridge circuit, and
wiring it in parallel. When you connect one of your windings across pins 3 & 6, you are also connecting that winding across pins 14 & 11, because section-1 is in parallel with section-4 and section 2 is in parallel with section-3.
8 go to 12V
12 go to 5V
1-9 go to 5V
2-15 go to logic 1
3-14 go to logic 2 (opposite of logic 1)
6-11 go to coil side 1
7-10 go to coil side 2
4-5-12-13 go to GND