Back EMF monitor for motor control

摘要

An integrated circuit includes a motor current input voltage-to-current (VI) converter that receives a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current. A motor current calibration VI converter compensates for errors in the motor current input VI converter and generates a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current.

主权项

1. An integrated circuit comprising:
a motor current input voltage-to-current (VI) converter configured to receive a motor current sensor voltage from a motor and a reference voltage to generate an output current related to a motor's current; and a motor current calibration VI converter configured to compensate for errors in the motor current input VI converter and to generate a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's current; a stage amplifier configured to amplify current from the summing node, wherein output from the stage amplifier is fed back to the motor current calibration VI converter to control stage gain and is fed to a back electromotive force (BEMF) stage, the BEMF stage being configured to compute a BEMF voltage for the motor; a motor voltage input voltage-to-current (VI) converter that receives a motor voltage sensor voltage from the motor and a reference voltage to generate an output current related to the motor's voltage; and a motor voltage calibration VI converter to compensate for errors in the motor voltage input VI converter and to generate a calibration output current based on the reference voltage, wherein the output current and the calibration output current are combined to form an estimate of the motor's voltage; and at least one calibration digital to analog converter (DAC) to supply a calibration voltage to at least one of the motor current calibration VI converter or the motor voltage calibration VI converter.