New hybrid mode current controller with fast response without sub-harmonic oscillation

An wide bandwidth current controller is required for fast charging / discharging of supercapacitor applications. To do this, peak current mode is generally used, which has fast response characteristics. On the other hand, the peak current mode control must have a slope compensation function to restrain sub-harmonics oscillation. However, if the controlled output voltage is varied, the slope must be changed accordingly. However, it is not easy to change the slope by every changed output voltage. As other solution, the slope is selected as the maximum value, a slow response problem occurs. Therefore, in this paper, we propose a hybrid mode controller that uses a peak current and a newly specified valley current. By the proposed hybrid mode control, the sub-harmonic oscillation does not occur when the duty is larger than 0.5 with fast response.