DRV8308: The VHSG don't output the right Frenquency PWM

Supplementary explanation:
I mean the UHSG VHSG WHSG didn't output the right PWM .

Hello,

Thanks for posting on the MD forum!

Could you tell us which version of the GUI you are using? Is it the online version or the downloaded version?

Regards,

-Adam

Hello , Adam , 

I didn't use GUI , and I designed the PCB myself , and i write the DRV8308's register with my MCU .

I am sure i write the register successfully , and the value is in the above detail .

Thanks

lining

Lining,

Please share your schematic.

Regards,

-Adam

DRV8308.pdf

Hello , Adam , 

please have a  look abou tthe file i upload .

And I set the Enable =1 .

Summary :

(1): I set the DRV8308 to  "Internal Register PWM Mode " 

(2): I write DRV8308 's register by SPI 

(3): I set the some registers , and when i set "The PWM frequency used on the external FETs "= 25K , or 50K , or 100k, the motor can not run .But the motor shake.

When i set the frequency =200K , the motor can run .

So I think i don't find the right register value , when i set the frequency to 25K /50K /100k . Which registers i should pay attention for  ?

I have two doc about the DRV8308 , one it the datasheet  , and another is the user guide , are there any other files about DRV8308 ?

Thanks

lining

Hi ， Adam , 

do you any suggestions about my problem ?

I set the DRV8308 to "Internal Register PWM Mode"

why the 25Khz, 50K hz , 100K hz frequency PWM can not make the Motor run  ?

Can all frequency PWM can make the motor run when I set the right parameter ?

Look forward to your reply .

Thanks

lining

Lining,

Do you have the DRV8308 EVM and device GUI? I would like to try these so that you can easily tune the settings for your motor.

Can you show a picture of the motor and hall connections to your PCB?

Regards,

-Adam

Lining,

Have you checked if any FAULT is occurring during your operation at lower PWM frequency?

Can you share your motor details with us? What is the phase inductance?

Regards,

-Adam

Hello, Adam , 

(1): the fault was occuring during my operation .

when i run in 25K hz & 50Khz  , there always  show " overtemperature shutdown" & " motor OCP"; and motor can not run ;

when  i run in 100k hz , there always show " motor OCP" , and the motor can run , but not smooth and very slow .

when i run in 200k hz , there appear one " motor OCP" , and then disappear . and motor can run , and it is smooth .

Are these normal ? and why ?

(2):i can not get the mortor details about the phase inductance .The motor supplier didn't provide us the parameter.Does these parameters will lead to these behavior ?

(3):I am buying the EVM board , and it 's under shipping .

Look forward to your reply .

Thanks

lining

hello, Adam : 

there is my new test result :

I use in the register speed mode 

(1): when i change the Duty cycle , it's high level time will change , when the high level time bigger than  t_OCP , it will occur OCP.

(2): when i set the  the OCPDEG=0,0 .    t_ocp = 1.6µs, t_BLANK = 2µs . when i set the high level time bigger than t_ocp , it will not occur the fault. But auto set the high level time to 500ns .

Does this two behaviors normal  ? and why for the (2) ?

Thanks

lining

hello ,Adam , I test my PCB again . and i also test the EVM board of DRV8308 .

we find that we set the same register value , and the EVM board can drive the motor but my PCB can not drive the motor .

I am sure my circuit schematic was the same as the EVM Board's .

So if there any problems about the  PCB layout and PCB wires ?

where do I need to pay special attention about the PCB Layout and the PCB Wires ?

look forward to your reply .

Thanks 

lining

Lining,

Sorry for the delay, did you resolve your issue here?

Regards,

-Adam