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Control 4 motors, each with its own speed


LuigiCRD
(@luigicrd)
Active Member
Joined: 5 months ago
Posts: 6
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Hello,

I'm building a 4WD car, and I want to control the speed of each of the wheels. At the moment I'm controlling the motors with an L298N, but I'm thinking to use a smaller driver since two L298N would occupy too much space on the car.

As a logic replacement, the TB6612NFG would be the choice, but I'm considering the DRV8833 because as I read it occupies fewer pins.

About this driver I have a doubt because I can't find much about it: can one DRV8833 manage the speed of two motors separately as the L298N and the TB6612NFG?
I've not understood if the PWM signal for the speed goes to the input pins of the motors or to the "SLEEP" pin to enable/disable the driver itself, in the first case it could manage the speed of each motor, but in the second, both of the motors would always be subject to the same duty cycle.

Could anyone clarify my doubt about the DRV8833?


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jker
 jker
(@jker)
Eminent Member
Joined: 11 months ago
Posts: 44
 

The TI data sheet shows two DC motors running from a single 8833 on the functional block diagram on page 8. https://www.ti.com/lit/ds/symlink/drv8833.pdf   It might be a little confusing because it shows a stepper on the same diagram, but that's an "either/or" diagram.

The DRV8833 can be run via a PWM signal into the input pins under either a fast or slow decay cycle by grounding or fixing high the "other" pin.

Usually the sleep pin is for shutting the entire chip off, not for motor control. NSLEEP low puts the DRV8833 into sleep mode and resets the internal state. It could conceivably work as a control pin... but the device only guarantees a 1ms maximum sleep to on-time, with no range or typical time specified.

"A resistor makes a lightbulb and a capacitor makes an explosion when connected wrong"
"There are two types of electrical engineers, those intentionally making antennas and those accidentally doing so."


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LuigiCRD
(@luigicrd)
Active Member
Joined: 5 months ago
Posts: 6
Topic starter  

I already did look at that link, I'm not much used to read datasheets, especially those having that level of detail, but thanks to your message I've understood where to get the information I needed. I've also learnt something I didn't know at all: fast/slow decay.

Thank you


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