Digital Control of High-Frequenc

　　A number of DPWM controller architectures and implementation strategies have been investigated and realized in practice. Many standard microcontrollers and DSP chips are now available， featuring multiple high-resolution PWM and analog-to-digital （A/D） channels， which allow software-based implementation of control and management functions. While advances in this area have been rapid， the software-based approaches are still better suited for applications where switching converters operate at relatively low switching frequencies. On the other hand， at switching frequencies in the hundreds of kilohertz to megahertz range， specialized hardware-based control loops are often preferred. This approach is illustrated in the architecture shown in Fig. 1 ［12， 13］。 The control loop is digital， using specialized， programmable A/D， DPWM， and compensator blocks to achieve high-performance closed-loop dynamic responses， while programmability， power management， and system interface functions are delegated to a microcontroller core. Similar combinations of programmable hardware peripherals specialized for switched-mode power converter applications， with software-based realizations of higher-level management and communication functions are often found in commercially available DPWM controllers. Controllers of the type shown in Fig. 1 can be developed， realized， and tested using standard digital VLSI design flow starting from logic functions described using