This is a placeholder topic for “TB9051FTG Single Brushed DC Motor Driver Carrier” comments.
This breakout board makes it easy to use Toshiba’s TB9051FTG brushed DC motor driver. It has a wide operating voltage range of 4.5 V to 28 V and can…
Read moreI’m trying to use the TB9051FTG Single Brushed DC Motor Driver Carrier. So far two of the ones I’ve tried to use are no longer working and the diagnostic pin has been pulled low and I cannot determine the cause. I’ve just pulled out a brand new one and wired it up to a breadboard, using a 3.3v signal as a 100% pwm duty cycle input to the enable pin and a high signal to pwm1. I’ve grounded the enable b pin and pwm2. According to the truth table this should cause it to drive forward but I’m getting no voltage output. Please help!
Hey @Laura214244,
Sorry to hear you’re having issues with the board!
First off, is there any chance you could send some images of your setup? Hopefully that way we can rule out the simple stuff. I’m looking over the datasheet now, I’ll let you know if anything sticks out immediately.
Also, I notice you mentioned two of the boards you are using “no longer” work, does this mean you had this setup driving the motors successfully previously?
Hey @Laura214244,
Notice the paragraph at the bottom of this image,
I believe you are using this configuration method. Seeing as the minimum Toff is 80 microseconds, I fear that feeding a constant voltage to simulate a 100% duty cycle PWM signal may not work. This is more referring to the fact that you cannot achieve more than 90% regardless of the input, but this driver has a lot of input protection, so it’s possible that is the issue.
I would try feeding it a safe duty cycle of around 50% to test.
Let me know how this goes!
Hi Laura
That should be correct
It is not quite clear where you are measuring.
Have you got a motor connected or are you just measuring output volts.
If just measuring output volts you should be measuring ACROSS the output points between “Out 1” and “Out 2”, NOT with respect to ground.
100% duty cycle should be full logic high. Is this the case? Try disconnecting the logic signal and applying a HIGH to the PWM input. The motor should go full speed or measure full volts at the output.
You can check the presence of a PWM signal if you don’t have an oscilloscope. Use a DC Multimeter and it should read the AVERAGE DC voltage. That is say for 50% duty you should read 50% of logic high. For 5V logic that would be 2.5V.
I do note the voltage applied to VCC should be regulated 5V. Is this your case.
As there does not seem to be a 3.3V regulator on board I assume the logic operating voltage to be 5V.
Also there seems to be no mention of the required PWM logic level. It could be 5V as mentioned above so if you are using 3.3V this may not be high enough. Perhaps Core can advise on the PWM level requirement.
Cheers Bob
Zac popped in while I was replying. He could well be correct here and you need a PWM signal. But at 100% this signal is going to be a steady logic HIGH if using an Arduino or any of the boards I have used so if Zac is indeed correct some modification of the driver software would be required to prevent a full 100% input.
Hey @Laura214244, @Robert93820,
Good idea re: PWM logic level Bob, I was in the process of checking this. The datasheet for the IC itself doesn’t ever seem to mention 3V3 logic level explicitly. Though it should work per the table below (found on the IC’s datasheet).
VIH (Input Voltage High) a.k.a. the “high” state of a PWM input, seems to be able to range from 1.75V - Vcc. So while the chip was designed with 5V logic in mind, it seems 3V3 PWM logic should work fine, though you will likely have a lower maximum motor speed. The max motor speed achievable with this setup would be as follows:
New Max Speed = (Motor Max Speed)*(3.3/5)
Regardless, try some of these suggestions @Laura214244, if you’re still having trouble I would post pictures of your setup.
Hope this helps!
Hi Zac
The PWM input voltage level will be completely divorced from the pulse output level which will be the same (or should be) as the motor drive input voltage.
So
would not be so.
The motor speed would be determined by both the actual drive voltage (the motor supply voltage) and the pulse WIDTH of the PWM signal. PWM being “Pulse WIDTH Modulation”. As I mentioned above when measured with a DC meter you will read the AVERAGE of the DC pulsed signal so 50% will read half the drive voltage.
You are correct though in that according to the IC data sheet this should be quite OK with 3.3V logic.
Cheers Bob
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