DRV120: The fpwm is10khz with Rosc is 0 ohm.it is not meet datasheet, or it is nomal?

Hello

Thank you for reaching out to us.

As explained below, whe Waveform looks correct to me. If you have any issue with current, please share the waveform to me. 

As illustrated in the DRV120 7.3 Functional Block Diagram, the PWM clock (PWMclk) is constant and set by the OSC pin, similar to the DRV110 structure with an external FET. For reference, please see the DRV110 datasheet, specifically Figure 3: "DRV110 Current Control with Varying OUT Duty Cycle". This figure shows that the output voltage (VOUT) becomes low when VSENSE is greater than or equal to VREF, with a minimum duty cycle of 8%. Otherwise, VOUT remains high for several periods to provide the determined current.

Regarding the screenshot you shared, the captured delta of 10.6 kHz appears to be incorrect. To accurately assess the situation, we recommend comparing VOUT with the load current to verify if the current is set to the determined value. Then, calculate the frequency for that specific period. Notably, the frequency calculation in your screenshot indicates a setting of 20 kHz. Please check the Figure 3 to find how to measure the frequency. The VSENSE can be substitute with load current in DRV120. 

Figure 3. DRV110 Current Control with Varying OUT Duty Cycle

                                DRV120                                                                                          DRV110

Best regards, 

Mojtaba.