Patent ID: 6114826
Filing Date: 2000-09-05
Classification: H02P

Abstract:
An apparatus for driving a stepping motor in a micro step manner by a PWM control signal generated based on a sense voltage, comprising:first and second power supply terminals;a first switching element connected between said first power supply terminal and a first terminal of said stepping motor;a second switching element connected between a second terminal of said stepping motor and a reference resistor;a third switching element connected in parallel to said second switching element, an ON resistance of said third switching element being larger than an ON resistance of said second switching element;a sense resistor, connected between said second switching element and said second power supply terminal, for generating said sense voltage; anda fourth switching element connected between the first terminal of said stepping motor and said second power supply terminal,and first, second and third switching elements being turned ON and said fourth switching element being turned OFF, when being PWM signal is activated,said third and fourth switching elements being turned ON and said first and second switching elements being turned OFF, when said PWM signal is not activated.