A method for driving a motor by imposing the current in the motor by means
of power current mirrors is presented. This allows driving the motor in
current with higher accuracy and lower electrical noise. The Hard Disk
Drive application is an example where higher resolution is required for
the VCM motor. Furthermore this method reduces the complexity of the
system eliminating components and high performance circuits. Moreover
this approach reduces the development and manufacturing cost by
simplifying the testability and the analysis of the system. The intrinsic
elimination of DC offset also takes out the need for the system offset
calibration phase and significantly improves on the harmonic distortion
of the transfer function. Furthermore this method offers the advantage of
faster overall response of the system and higher efficiency. The
additional benefit of this method is the ability to have a motor drive
system that can be easily and smoothly switched between a PWM drive and a
linear drive for different modes of operation of the motor itself.