Motor Driving Circuit and Method

摘要

A motor driving circuit for driving a direct-current (DC) motor, includes a driving circuit for converting an input voltage into a first and a second output voltages, a Hall sensor for generating a first and a second time sequential control signals according to a working condition of the DC motor, a current sensing unit for comparing the motor current to a reference current to generate a comparison result, and a control unit coupled to the driving circuit, the current sensing unit and the Hall sensor for controlling a working status of the driving circuit according to the first and the second time sequential control signals and the comparison result.

主权项

1. A motor driving circuit for driving a direct-current (DC) motor, comprising:
a driving circuit, for converting an input voltage into a first output voltage and a second output voltage, the driving circuit comprising:
an input terminal, for receiving the input voltage;a first output terminal, for outputting the first output voltage;a second output terminal, for outputting the second output voltage;a first transistor, coupled between the input terminal and the first output terminal, for switching a conduction condition of the input terminal and the first output terminal according to a first transistor control signal;a second transistor, coupled between the first output terminal and a grounding terminal, for switching a conduction condition of the first output terminal and the grounding terminal according to a second transistor control signal;a third transistor, coupled between the input terminal and the second output terminal, for switching a conduction condition of the input terminal and the second output terminal according to a third transistor control signal; anda fourth transistor, coupled between the second output terminal and the grounding terminal, for switching a conduction condition of the second output terminal and the grounding terminal according to a fourth transistor control signal; a Hall sensor, for generating a first time sequential control signal and a second time sequential control signal according to a working condition of the DC motor; a current sensing unit, coupled to the first output terminal and the second output terminal, configured to compare a motor current through the DC motor with a reference current and generate a comparison result; a control unit, comprising:
a counter, coupled to the current sensing unit, configured to generate a counting output according to the comparison result;a digital-to-analog convertor, coupled to the counter, configured to generate a first reference voltage and a second reference voltage according to the counting output;a first comparator, coupled to the digital -to-analog convertor and the Hall sensor, configured to generate a first transition voltage according to the first time sequential control signal, the second time sequential control signal and the first reference voltage; anda second comparator, coupled to the digital-to-analog convertor and the Hall sensor, configured to generate a second transition voltage according to the first time sequential control signal, the second time sequential control signal and the first reference voltage; anda logic unit, coupled to the first comparator, the second comparator, first transistor, the second transistor, the third transistor, and the fourth transistor, configured to generate the first transistor control signal, the second transistor control signal, the third transistor control signal and the fourth transistor control signal according to the first transition voltage and the second transition voltage; wherein when the comparison result indicates that the motor current is higher than the reference current, the control unit adjusts the first transition voltage higher; wherein when the comparison result indicates that the motor current is lower than the reference current, the control unit adjusts the first transition voltage lower.