DRV8825: DRV8825 current values in RMS / peak-to-peak / peak value?

Hey Jerry,

Thank you for your question.

I chop is referring to the maximum current the output current is limited to. Once the current hits the current chopping threshold, the bridge disables the current until the beginning of the next PWM cycle.

The continuous motor drive output current is referring to the RMS current and we do not recommend exceeding the 2.5 A abs max spec of this driver.

The OCP is the value of current above which the device disables the outputs. An analog current limit circuit on each FET limits the current through the FET by removing the gate drive. If this analog current limit persists for longer than the OCP time, all FETs in the H-bridge will be disabled and the nFAULT pin will be driven low. The device remains disabled until either nRESET pin is applied, or VM is removed and reapplied. Note that overcurrent protection does not use the current sense circuitry used for PWM current control, and is independent of the ISENSE resistor value or xVREF voltage.

The 3A OCP is the minimum threshold at which an OCP event may be triggered, but it might vary based on temperature, load current, voltage etc. So the OCP in your system might be higher than 3A.

Hope this offers some clarification.

Best,

Akshay

Hey Jerry,

OCP refers more so to the peak current, it is the maximum current that the device can sustain before getting shutdown to protect the driver.

I recommend watching this training video which explains the concept in more detail.

https://training.ti.com/zh-tw/peak-vs-rms-current

RMS current is more closely related to thermal shutdowns/warnings where the device is shut down if the IC starts getting too hot due to potentially high current.

Best,

Akshay