CCS/DRV8301: No pwm output when the PVDD1=Vbus higher than 14V

Part Number:DRV8301

Tool/software: Code Composer Studio

Hi all,

In my case, the PVDD1 and Vbus of MOSFET are connected. PVDD2 is float.No SPI connected (using the default value).

When I put the Vbus below 14V, the output PWM is good. (Fig.1, the yellow and pink are input PWM, blue and green are output PWM)

However, I put the Vbus higher than 14V the output PWM are closed (=0). (Fig.2, the yellow and pink are input PWM, blue and green are output PWM)

A protection occurred, when I put higher than 14V then the nFAULT is low.

Any problem may cause the protection? I've check the OV, UV protection, and there is no load connected to the inverter.

By the way, what is the default value of  the OC_ADJ_SET in the Table 13?

Fig.1

Fig.2

Thanks in advance,

Bojun Wang.