A low-cost digital controller for a switching DC converter with improved voltage regulation

A new control algorithm with improved regulation is presented for a switching dc buck converter. The controller is realized with hardware description language (HDL) and can be implemented in any process. The controller uses four decision levels, combines pulse frequency modulation (PFM), pulse width modulation (PWM), and uses dithering for improved regulation. The controller is prototyped on a field programmable gate array (FPGA) and experimental results show good performance over input and load disturbances. Importantly, the controller does not require high resolution analog-to-digital conversion for signal processing, and also does not require fast digital clocking. This controller has significant potential to be widely used in industrial applications where cost and design time are of great concern.