Motor control circuit with adaptive controller path selection for different load conditions

摘要

A motor control circuit for controlling rotation of a motor includes parallel first and second controller paths (gears). Each path includes a proportional and integral (PI) controller and a digital to analog converter (DAC). The DACs operate over different dynamic ranges (gains). The respective PI controllers have different control parameters to provide a common frequency response. The first controller path is used to output motor control signals to control the application of drive current to the motor. The circuit switches to the second controller path once the first controller path operates within a selected tolerance of a minimum or maximum level of the first dynamic range. The final state of the first PI controller is used to configure the initial state of the second PI controller to eliminate transients. The use of different gears allows the circuit to adaptively accommodate large variations in motor current and spindle motor configurations.