L9110 doesn't work depending on power input

Projects General Guidance
1

I am trying to control a 12v fan with a L9110 module and an Arduino Uno. If I connect the Vcc and Gnd pins of the L9110 directly to the terminals of a 12v power supply and power the arduino with 5v via usb, it doesn't respond to signals sent by the arduino. If I try instead to power the arduino from the 12v supply via it's barrel jack, and THEN connect Vin and Gnd of Arduino to Vcc and Gnd of L9110, everything works fine.
Any ideas what might be the cause?

2

In both cases you connect GND of the 12V power supply with the GND of the Ardino, right?

3

In the first case, I have Vcc and Gnd on the L9110 going to +12V and Gnd on the power supply. The Arduino is completely isolated from the 12v supply.

In the second case, I have Vcc and Gnd on the L9110 going to Vin and Gnd on the Arduino, which is connected to the power supply via a barrel jack.

4

Why? Why not use a logic level N channel MOSFET transistor?

Schematics please...
A link to the datasheet of the L9110 would several helpers.

5

Why? Why not use a logic level N channel MOSFET transistor?

It's because that's what I have at hand at the moment.

A link to the datasheet of the L9110 would several helpers.

[l9110 2-channel motor driver - LaskaKit https://www.laskakit.cz/user/related_files/l9110_2_channel_motor_driver.pdf](l9110 2-channel motor driver - LaskaKit https://www.laskakit.cz/user/related_files/l9110_2_channel_motor_driver.pdf)

6

Can we please have a circuit diagram?
An image of a hand drawn schematic will be fine, include ALL power supplies, component names and pin labels.

Did you read @MaximoEsfuerzo post?

Thanks.. Tom.. :grinning: :+1: :coffee: :australia:

7

You must connect GND of both.
That's why it doesn't work powered by USB.

Regards

8

penup_20230811_094457
penup_20230811_0944571080×1620 118 KB

penup_20230811_094010
penup_20230811_0940101080×1620 106 KB

#1 doesn't work, #2 works

9

af84ba411e5adc42fe7041f88659aad032c6e460_2_499x750
af84ba411e5adc42fe7041f88659aad032c6e460_2_499x750499×750 47.5 KB

You understand?

10

Your setup should be something like Fig-1; where, GND-pin of 12V supply must be connected with GND-pin of UNO (Fig-1) as has been pointed in the earlier posts.

motorDriveL9110
motorDriveL9110799×410 104 KB

Figure-1:

Sample Sketch: (not tested)

void setup()
{
     analogWrite(6, 200);
     analogWrite(5, 0);
}

void loop()
{

}
11

I see... So there has to be a ground loop between the Arduino and power supply

12

It is more than above and is stated below:

Among Arduino's GND-pin, Motor Driver's GND-pin, and +12V's GND-pin (Fig-1 of post #10).

13

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