The DRV8805 can output a current of up to 2-A (single channel on) or 1-A (all channels on) continuous output current (with adequate PCB heatsinking at 25°C).
The unipolar stepper motor is rated as follows:
Rated Current 1A / Phase
Voltage 5.7V
Winding Resistance 5.7Ω / Phase
Will I be able to drive this stepper with the DRV8805 motor driver at it's limit of 1A channel without encountering any thermal or other problems?
Thank you.
Hello Rick,
Thank you so much for your prompt reply.
I, initially, intended to use the Onsemi STK672-630A-E. But when I came across the DRV8805 I thought it my be a better choice because of its small form factor, functionality (including OCP and thermal protection) and I thought that the output current of 2A is for all channels each until I read the datasheet more in detail.
As I mentioned in the previous email, the operating voltage of the stepper motor is 5.7V, the resistance is 5.7ohm/phase so the current is 1A/phase. The stepper motor is a 2-phase, unipolar motor. The model number of the stepper motor is PK264A1-SG36, the manufacturer is ORIENTAL MOTOR GENERAL.
Specifications:
Frame Size 60mm
Type SH Geared Type
Shaft Type Single Shaft
Motor Lead Wire/Connector Assembly -
Maximum Holding Torque 4N・m
Rotor Inertia J 120×10^-7kg・m^2
Backlash approximately 1˚∼2˚
Speed Range 0～50r/min
Gear Ratio 36
Basic Step Angle 0.05°
Rated Torque 4N・m
Rated Current 1A / Phase
Voltage 5.7V
Winding Resistance 5.7Ω / Phase
Mass: Motor 0.75kg
Yes, I have looked at other DRV88xx motor drivers including the DRV8846. The reason, I have not considered it and other drivers like the DRV8825 (using a bipolar driver for a unipolar stepper motor) is that it would increase the BoM size and would require a larger footprint. Space is a constraint for the PCB. so we're trying to make it small as possible. Please refer to the output connections to the motor as attached.
Thank you.
Regards,
Ismail.
