| 摘要 |
PROBLEM TO BE SOLVED: To achieve stable current mode control by a smaller-scale circuit without using a slope compensation circuit even under a condition where an I/O voltage varies.SOLUTION: A switching power supply unit 1 controls with a peak current detection system when a duty ratio of a PWM signal is 50% or less and with a valley current detection system when the duty ratio of the PWM signal is more than 50%; therefore, no sub harmonic oscillation occurs. Thus, slope compensation is not required and hence stable current mode control can be performed. |
