DRV8307: Do not drive MOSFET

Ahn,

What makes you think the device is damaged?

I don't see any obvious issue with your schematic but you may have some setup or procedure incorrect.

Could you tell us the status of your Brake and nFault pins?

Regards,

-Adam

Hi  Adam.

Thank you for your reply.

I am not sure DRV8307 were damaged, but when I bought other parts there were defective parts occasionally.

PWM frequency is 25Khz and BRAKE signal goes to LOW about 1ms before nENABLE active.

 

Ch1(yellow) : nENABLE

Ch2(blue) : nFault

Ch1 : nENABLE

Ch2 : HSG

Ahn,

Have you tried the startup without a motor or load on the output? If not, please try this and check for output switching.

Have you seen the output switching at all? Or just this DC level after the enable?

Regards,

-Adam

Hi Adam.

I have tried with / without a motor but the results were the same.

I have not seen the output switching untill now even I tested with motor.

Power VM is supplied +24V.

Best regards.

Ahndy.

Ahndy,

Sorry for the delay here, do you have any update or further information?

Regards,

-Adam

Hi Adam.

Thank you.

I don't find the cause of problem and solution yet.

I assembled the same other PCB and tested it, but the result was the same as provious one.

I thought the DRV8307 was the most suitable component for this project in terms of simple circuit and low cost.

But I spent too much time to solve this problem, so I am reviewing other gate drive IC specifications.

Best regards.

Ahndy.

Ahndy,

Have you tried to use the EVM for this device? If not, I can provide you one. This may help having a second working example to double check.

Regards,

-Adam

Hi Adam.

I have no EVM,

I appreciate it if you send me a EVM.

Please let me know  the account number and amount that I have to transfer.

I will check the connection and pattern difference between my PCB and EVM.

My address is like the profile and I will let you know if you do not know.

Best regards.

Ahn do-yoon

Hi ADAM.

I  found a problem.

Three high side MOSFET drive signals show the waveform as the attached image.

When  run the motor continuously, only three high side MOSFETs generate a lot of heat.

The gate drive signal shows the same waveform every time.

Best regards.

Ahndy.

Ahndy,

Do you know if your FETs are fully turning on? Maybe they are still in their resistive region and the increased RDSON is causing heating.

Regards,

-Adam

Adam.

Thank you very much for your reply.

How do I know if the FETs are fully turning on?

PWM with 70% duty-ratio is supplied without acceleration / deceleration.

The Vgs(th) of IRFR7546 is described as max 3.7V in datasheet.

I attached two screenshot.

1. picture 1.

- Channel 1 :  V high side gate signal

- Channel 2 :  V signal

2. picture 2.

- Channel 1 : V hallout signal

- Channel 2 : V signal

Best regards

Ahndy

Adam.

I have two questions.

1. Is channel 1 wavwform of the below screenshot normal?

   The waveform differ from the GHA wavwform(picture 35, page32) in the DRV8306 datasheet.

2. Some motor runs normally with other driver but does not run with DRV8307 driver.

Best regards.

Ahndy

- Channel 1 : V HSG (drv8307 pin 35)

- Channel 2 : V signal (DRV8307 pin 36)