L
Larty
Hi,
Does anyone have any good ideas for a programmable current source/sink
circuit that can drive an inductive load (stepper motor coil)?
I'm trying to microstep a 2 phase stepper motor at high speeds in
order to try and reduce the level of audible noise produced. This
means driving both coils with two sine wave currents 90 degrees out of
phase.
I have searched for PWM type current drive chips, but these all seem
to only operate with a maximum chopping frequency of around 100kHz -
this would give less than 1 chopper cycle for each microstep at the
speeds I want to go at (2000 degrees/sec, 1.8 degree per step, 128
microsteps per full step). Hence I was wondering if it is possible to
use a constant current drive approach rather than the normal PWM
approach. The current will be programmed via a microcontroller and DAC
and will need to be accurate to around 14 bits, with a new value
around every 7us. The full scale current is likely to be +/-1A.
Thanks in advance.
Larty.
Does anyone have any good ideas for a programmable current source/sink
circuit that can drive an inductive load (stepper motor coil)?
I'm trying to microstep a 2 phase stepper motor at high speeds in
order to try and reduce the level of audible noise produced. This
means driving both coils with two sine wave currents 90 degrees out of
phase.
I have searched for PWM type current drive chips, but these all seem
to only operate with a maximum chopping frequency of around 100kHz -
this would give less than 1 chopper cycle for each microstep at the
speeds I want to go at (2000 degrees/sec, 1.8 degree per step, 128
microsteps per full step). Hence I was wondering if it is possible to
use a constant current drive approach rather than the normal PWM
approach. The current will be programmed via a microcontroller and DAC
and will need to be accurate to around 14 bits, with a new value
around every 7us. The full scale current is likely to be +/-1A.
Thanks in advance.
Larty.