Digital Linear Slope Control Method for Improving the Load Transient Response of a Buck Converter

The paper presents digital linear slope control (LSC) method for reducing the overshoot and undershoot of the output voltage of a buck converter during the load transient. The method suppresses the output voltage fluctuation by modulating the slope of the control signal only during the load transient interval. The digital LSC method utilizes the output voltage information only. Thus, it does not require additional circuit components compared with the conventional voltage-mode control. Furthermore, the burden of microcontroller is minimized by using simple math functions such as adding and subtracting operation. A load transient detector is presented to detect a load transient. The relationship between the slope and the output voltage deviation is analyzed to validate the method. The performance of the LSC method is verified on a 15 V-5 V prototype buck converter operating at 100 kHz.