Low transient voltage dual loop buck converter using digital charge control technique

A digital control dc-dc buck converter with dual voltage feedback loop is presented to achieve good transient performance. Unlike conventional voltage mode buck converter which uses linear controller, such as PID control, the transient response is limited by the control bandwidth and switching frequency. The proposed dual loop system adds an extra control loop with charge control technique to improve the transient response. Also, the transient output voltage of the buck converter can be suppressed under 3.5% of the output voltage. The digital controller is implemented by FPGA and power stage is implemented by PCB with discrete component. Experimental results demonstrate the superior transient output voltage over that of a conventional linear controller.