Patent ID: 7630616
Filing Date: 2009-12-08
Classification: G11B,H02P,H03K

Abstract:
1. A coil load driving circuit that drives a coil load in a positive or negative direction by applying a PWM pulse in accordance with a difference between an input control voltage and an input reference voltage to either terminal of the coil load, comprising: a transfer voltage generating circuit that inputs the input control voltage and the input reference voltage, and, depending on a difference thereof, outputs a first transfer voltage that increases and decreases about a center voltage of a triangular wave signal that is output by an oscillator and a second transfer voltage that increases and decreases oppositely to the first transfer voltage about the center voltage of the triangular wave signal that is output by the oscillator; a first PWM comparator that outputs a first PWM signal by comparing the first transfer voltage and the triangular wave signal; a second PWM comparator that outputs a second PWM signal by comparing the second transfer voltage and the triangular wave signal; an output PWM pulse synthesis circuit that outputs an AND signal of the first PWM signal with an exclusive OR signal of the first and second PWM signals and that outputs an AND signal of the second PWM signal with the exclusive OR signal of the first and second PWM signals; a first output buffer arranged to output a PWM pulse at one terminal of the coil load, being controlled by the AND signal of the first PWM signal and the exclusive OR signal; and a second output buffer arranged to output a PWM pulse at the other terminal of the coil load, being controlled by the AND signal of the second PWM signal and the exclusive OR signal.