Load driving control apparatus

A load driving control apparatus for controlling driving of an inductive load, the load driving control apparatus comprising:

• a switching element provided in a current supply path to the inductive load to supply current to the inductive load when turned on;
• an actual current value detection part for detecting an actual current value, which is supplied to the inductive load;
• a duty ratio setting part for setting a duty ratio based on the actual current value and a target current value, which is a target value of the current supplied to the inductive load;
• and
• a PWM driving part for generating a PWM signal having the duty ratio, which is set by the duty ratio setting part, at a predetermined cycle period and outputting the PWM signal to the switching element,
• wherein the duty ratio setting part includes a slope calculating part, a first calculating part and a second calculating part,
• the slope calculating part calculates a first slope and a second slope indicating slopes of currents in an on-period and an off-period in one cycle period of the PWM signal, respectively, by using the actual current values at a start time point and an end time point of the PWM signal as well as two sets of data, which includes the duty ratios corresponding to the actual current values and the actual current value of predetermined one of the start time point and the end time point of which is within a predetermined current area,
• the first calculating part calculates the duty ratio based on a difference between the target current value and the actual current value, and
• the second calculation part calculates the duty ratio based on the first slope, the second slope, the actual current value at the start time point and the target current value, when a predetermined one of the current values between the actual current value at the start time point and the target current value is within the current area, and
• wherein the PWM driving part generates the PWM signal by using the duty ratio calculated by the first calculating part until calculation of the first slope and the second slope is completed and generates the PWM signal by using the duty ratio calculated by the second calculating part after the calculation of the first slope and the second slope is completed.