AUTO CALIBRATION DRIVER IC AND ITS APPLICATION MOTOR DRIVER SYSTEM

摘要

A motor driver IC with auto calibration function is provided, the motor driver IC utilizes a Hall sensor of a switched sensor circuit to detect the changes in an external magnetic field. By using the compensation current which is generated by the automatic calibration circuit to correct the unexpected offset existed in the Hall sensor of the sensing unit itself to zero so that the sensing unit can sense the changes in the external magnetic field accurately and can point out the rotor position correctly, and the motor can be further driven to commutate relatively to reduce the motor rotation noise to achieve good output performance of the motor rotation and the better motor driving system stability.

主权项

1. A driving chip with correction functions, comprising:
a sensing unit, which senses the changes in an external magnetic field and generates a first sensing voltage signal and a second sensing voltage signal; a pre-processing unit, which receives and amplifies the first sensing voltage signal and the second sensing voltage signal and outputs a offset voltage; a calculating unit, which includes one terminal that is electrically connected with the pre-processing unit and another terminal of the calculating unit is electrically connected with a reference voltage and outputs a first calculating signal and a second calculating signal; a gain adjusting unit, which is connected with the pre-processing unit to generate a first voltage controlling signal and a second voltage controlling signal; and a controlling unit, which includes a power-on delay circuit, a comparator and an automatic correction circuit, wherein a positive input terminal of the comparator is electrically connected with the gain adjusting unit for receiving the first voltage controlling signal and a negative input terminal of the comparator is electrically connected with the gain adjusting unit for receiving the second voltage controlling signal, after comparing the first voltage controlling signal and the second voltage controlling signal, the offset voltage can be determined to belong to a positive offset voltage or a negative offset voltage and outputs a controlling signal to the automatic correction circuit, when the power-on delay circuit counts a counter to a presetting delay time to generate a start signal to trigger the automatic correction circuit and at the same time, an enabling signal is provided for triggering the gain adjusting unit to adjust a gain factor, the automatic correction circuit generate a compensation current that returns to the pre-processing unit to correct the positive offset voltage or the negative offset voltage to zero.