DRV8871 Breakout board not working!!!

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pzachkani
 
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DRV8871 Breakout board not working!!!

Post by pzachkani »

I have purchased three DRV8871 boards separately, and none of them are working. The first board was not working from the beginning. The second board worked for one hour, I came back and plugged the device back in, and it was not working anymore. The third one was not working either. My power supply is 12V and my maximum current draw is 1.8 A which is way below the specs of the breakout board (spec sheet says that the board can handle 3.6 A and operates at voltages 6.5-43 V). I have looked at my output with an oscilloscope and measured the voltage across the IC legs with a probe. NOTHING! changing the duty cycle for PWM does not change the voltages on the output legs at all. Also, it says that the board is protected against overcurrent and overheating. Even if there was overcurrent (which there wasn't because my setup is well characterized and I know exactly what the max and steady state currents are), it should not have affected the board. What is going on here? And how is it possible that none of the boards are working? (Technically one of them worked for an hour only and then died)?!!!
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adafruit_support_bill
 
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Re: DRV8871 Breakout board not working!!!

Post by adafruit_support_bill »

Please post a photo that shows all of your wiring. Also please post the electrical specs for the motors you are using.

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pzachkani
 
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Re: DRV8871 Breakout board not working!!!

Post by pzachkani »

I am using this board to control a thermoelectric module (peltier). Here are the specs:

SPECIFICATIONS
Running Current (A) 1.8
Startup Current (A) 2.3
Nominal Voltage (V) 12
Max Voltage (V) 15
Power Input (W) 22
Performance Tolerance ±10%

I also have to add that after the first two failures, when I wanted to test the third board, It was not connected to my load, just the power supply and arduino. I measured the output voltage to see if I see the same 12V on the output, and It was not working, even before I connect it to my load. (obviously I have coded the arduino to give me 12V on the output of the DRV8871 and be able to change the output voltage by pwm)
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adafruit_support_bill
 
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Re: DRV8871 Breakout board not working!!!

Post by adafruit_support_bill »

That should be a manageable load for the DRV8871. Please post the code you are using to drive it.

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pzachkani
 
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Re: DRV8871 Breakout board not working!!!

Post by pzachkani »

The device is malfunctional. All three of them. they don't work even with a simple code like below. I've done way more in-depth measurements to be able to tell the difference.

void setup(){
pinMode(2,OUTPUT);
pinMode(3,OUTPUT);
digitalWrite(2,LOW);
digitalWrite(3,HIGH);
}
void loop(){
}

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adafruit_support_bill
 
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Re: DRV8871 Breakout board not working!!!

Post by adafruit_support_bill »

These are the first reported failures I am aware of since we started producing these more than 2 years ago. The probability of you getting the only 3 defective ones is vanishingly small. It is either a bad batch of parts, or something specific to your application. I will check with our QA team.

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adafruit2
 
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Re: DRV8871 Breakout board not working!!!

Post by adafruit2 »

something you're doing isnt working or breaking these. its not compatible with your setup.
email support@adafruit for a refund - but dont get replacements it doesnt make sense to replace them, you'll probably just have the same issue. you'll need to find some other driver chip! we don't have any recommendations on what that may be though

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