Hi there,
I have a question regarding DRV8825 stepper motor driver.
The datasheet states that the maximum step frequency is 250 kHz. However there is also written that that Internal current control PWM frequency is 30 kHz.
There is also written:
The current through the motor windings is regulated using a fixed-frequency PWM scheme. This means that after any drive phase, when a motor winding current has hit the current chopping threshold (ITRIP), the DRV8825 will place the winding in one of the three decay modes until the PWM cycle has expired. Afterward, a new drive phase starts.
And this confuses me. How then stepping with frequency above 30 kHz is possible? Does it mean that the driver logic is actually ORing two events, one is a pulse from Step pin and another from PWM driver? Roughly speaking, step pulse drives the current through the phases, and then the comparator trips it when the phase current reaches the particular step trip value? And with step frequencies close to 250 kHz pwm actually doesn't play any role no more?
Thanks in advance.