DRV8829/ OCP trip level
Part Number: DRV8829
Hello Good day,
I have a DRV8829 setup like the typical application page in the datasheet, i am trying to drive a 12V, 0.5A typical linear actuator (it becomes open when it reaches one end).
I notice that the fault pin goes LOW when the linear actuator reaches one end indicating that the protection was activated. It can't be over-temperature because nothing goes hot,
it can't be under voltage because voltage supplied to VM is constant (12V), so it must be overcurrent, but i dont understand why since my linear actuator only reaches up to 0.5 A.
Motor Drive Solutions
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In reply to Wang5577:
In reply to Marion Ramos:
Hello Wang Li, I tried putting a series inductor of 25uH with the linear actuator and i still had the same problem, the fault pin gets low when the linear actuator goes to one end. Do you think it's the same issue with this one? except there he's using a drv8825 e2e.ti.com/.../1392704
1. Would you share the schematic to me through the e2e private message? I want to check I[4:0] pull-up resistor value and any other possible reason to cause this issue.
2. Would you check the output current to see the OCP triggering event when the motor moved to the end?
Hello Wang Li,
1. I tried using the current regulation, i now used 0.75 ohm resistor for Risense, so that gives me Ichop = (3.3V/(5*0.75)) = 0.88A.
then I used 0x0Dh on I[4:0] which sets to 60 % of full scale which will make about 0.88*0.6 = 0.53A but im still getting a LOW on the fault pin when the actuator reaches one end
2. At the bottom of page 9 of the datasheet it says "The overcurrent protection does not use the current sense
circuitry used for PWM current control, and is independent of the ISENSE resistor value or VREF voltage. "
3. I think this has something to do with disconnecting the motor while the drv8829 is driving it.
Marion, Do you mean the OCP is still triggered after adding the current sense resistor and 8.2uH series inductor?
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