I am a bit peeved about the baby Os lately. First I had two that had the LEDS soldered backwards. Now I have burned out two of the TB6612FNG motor controllers on other board. I find the rating on the website:
Continuous output current per channel: 1 A
Peak output current per channel: 3 A
to be optimistic. I burned out the first one driving a pair of small gear motors. I thought hmm, that’s strange, maybe it was something I did.
This time I used the example library and ramped the motor duty cycle up. At 12V when it exceeded 850 ma to one channel (1.1 Amp total) the motor shutdown. Subsequent powering just left the driver “hot to the touch” Perhaps you should derate the spec a bit and save me 2 $20 parts. Close inspection after subsequent powering shows a small bubble in the TB6612FNG. Maybe to get the full current we need to heat sink the drivers or make sure there is a full copper pad underneath that is bonded to the chip? I think this gets worse when you parallel the drivers as it definitely seemed like thermal runaway was the culprit so there is not just a current issue but a total power issue. A quick look at the datasheet (I should have done this first) shows that the package can dissipate ~.75W - 1.25W depending on the copper underneath. Since the RDSon is ~0.5 Ohms, it seems like there shouldn’t be thermal problems. Still, maybe these should be speced to dissipate a max wattage say 10W / channel. All this should caution about paralleling the channels on this driver.
I am sorry about the Baby Orangutans that were manufactured incorrectly with the backward LEDs. Did you receive our offer (via email) to replace the boards? I am also sorry about the damaged motor drivers. What are you using for your power supply? What motors were you using? What is the stall current at 12V? When you say “parallel the drivers” what do you mean? Please note that paralleling the outputs on a Baby Orangutan is bad because it makes it very easy to short the outputs together.
“I am sorry about the Baby Orangutans that were manufactured incorrectly with the backward LEDs. Did you receive our offer (via email) to replace the boards?”
Yes I did. It was no big deal to just reverse the LEDs using the rework station, it just threw me for a bit out of the box. Hence the “peeved”
" I am also sorry about the damaged motor drivers. What are you using for your power supply? "
0-30V 5A regulated supply x-tronic. First tests were at 5V then 12V (robot runs off a 3S 500mAh 20C cell so gobs of current are available.)
"What motors were you using?"
fingertech gold spark 50:1
"What is the stall current at 12V? "
Don’t know. I just loaded the motors (knuckle to wheel increasing pressure) and read the current with meter in series. The driver didn’t fail at stall, just under load. I suspect the stall current is above an amp!
"When you say “parallel the drivers” what do you mean? Please note that paralleling the outputs on a Baby Orangutan is bad because it makes it very easy to short the outputs together."
Context of the test was driving motors on both channels. This is more total wattage for the driver to dissipate.
Now am running a vnh3sp30 without any trouble. Also an old school L298N with a giant heat sink seems to be fine. Kudos to you for all the great products.
I am glad the VNH3SP30 driver is working well for you.
The TB6612FNG should be able to deliver that kind of power fairly comfortably, and the thermal protection should kick in before it gets damaged by overheating. I’m not sure what happened to your board, but my main suspicion is the damage was the result of a voltage spike (in our experience, the 15 V absolute maximum is a fairly strict limit). You could use an oscilloscope to see how stable the supply voltage at the board is and what the motor noise is like.
Please email us if you’d like to try again with a replacement.
