DRV8306: after some actions DRV8306 damaged means nBRAKE or PWM or DIR pin connect to GND

Amir Rayan

Part Number: DRV8306
Other Parts Discussed in Thread: CSD88537ND,

I design a circuit like DRV8306EVM board for drive a sensored BLDC motor with nominal voltage 24V and nominal current about 4A. My motors datasheet is available at:: https://datasheets.globalspec.com/ds/5488/MaxonPrecisionMotors/F55869DF-CFFD-4AC7-9822-80DC4BEA9557

so the circuit have DRV8306 as Brushless DC Motor Controller and gate Mosfet drivers, and CSD88537ND as Power Mosfets. now my motor doesn't have load so the driver current is so low.

I bought 20 number DRV8306 for testing but now I see some problems in DRV8306

after some effort for controlling my motor by DSC I saw sometimes my Driver didn't work. after impedance test of my driver I see nBRAKE or PWM or DIR pin of DRV8306 is connected to GND (about 10 ohm).

I don't know what is the problem. now I have 5 damaged IC.

I didn't check fault pin in my DSC program and enable pin is always 5V high. maybe checking and controlling this pins are important.

i would be thankful if you could help me to resolve my problem.

over 5 years ago

0 Amir Rayan over 5 years ago

Prodigy 120 points

I have to mention that my PWM frequency is 73kHZ and nBRAKE pin is always high

0 Adam Sidelsky over 5 years ago in reply to Amir Rayan

TI__Guru 65140 points

Rayan,

Thanks for posting on the MD forum!

As I am not sure what has happened to your devices, please use a scope and monitor these pins in question to check for any anomalies and let us know what you find. Please post screenshots when you can.

Regards,

-Adam

0 Adam Sidelsky over 5 years ago in reply to Adam Sidelsky

TI__Guru 65140 points

Rayan,

I have seen no update on this thread, did your issue get resolved?

I will mark this thread as closed for now but please post again if you need further assistance.

Regards,

-Adam

0 Amir Rayan over 5 years ago in reply to Adam Sidelsky

Prodigy 120 points

my problem is not resolved yet.

I want to know is it a common problem in DRV8306?

in the datasheet mentioned this pin pull down with 100k resistor. it seems strange result that I see after some efforts this pins connect to GND. it's ok at first but after long test this problem happened. power supply of IC is 24V and I have 5V enable and PWM,DIR and BRAKE have 3.3V in high logic with iso742. Vds and IDRIVE are HI-Z..

if anybody had a same experience I would be grateful know about it.

0 Adam Sidelsky over 5 years ago in reply to Amir Rayan

TI__Guru 65140 points

Amir,

We need more help to resolve this issue. Can you use a scope to check the nBrake, PWM, and DIR pins and check for overvoltage or undervoltage during your device testing and operation?

This is not a common issue.

Regards,

-Adam

0 Amir Rayan over 5 years ago in reply to Adam Sidelsky

Prodigy 120 points

Hi Adam

thanks for your replies

after some test i understood sometimes specially when the motor direction is change the signals changed too

sometimes result are worse than that you see above. I have to mention the yellow signal is PWM pin of DRV8306 and blue one is GND!

my designed circuit is:

maybe freewheeling diodes or a snubber circuit could help me I don't know.

what's your idea for solving this problem

0 Amir Rayan over 5 years ago in reply to Amir Rayan

Prodigy 120 points

can anybody suggest me a better IC?

0 Adam Sidelsky over 5 years ago in reply to Amir Rayan

TI__Guru 65140 points

Amir,

You likely have an issue with your board layout or GND if you are seeing +10V or -10V on your GND node. This is violating the ABS max of the DRV8306. If you can share your layout, I can review it and give some recommendation.

Regards,

-Adam

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DRV8306: after some actions DRV8306 damaged means nBRAKE or PWM or DIR pin connect to GND