Digital Controlled Power Supply
Much time, effort and funds have been devoted to the development digital controllers for switch mode power supplies (SMPS) because of the several key advantages that microcontrollers offer. Traditionally, power supply technology has resided in the analog domain. Digital controllers have opened a completely new dimension and world for SMPS. In fact, this digital revolution for power supplies has grown considerably in recent years and allows power supplies to reach new levels.
Using a digital signal controller (DSC) offers several advantages to a power supply. DSC reduces part count thus providing a cost savings over a comparable analog approach. This reduction in part count also reduces board real estate.
The microcontroller allows a power supply designer to quickly redesign with few, if any, component changes or board revisions. Additionally, advanced power supply circuits, topologies and features can be easily implemented using DSC. The switching frequency can be adjusted for the SMPS to operate at the most efficient level which can be a function of the load or other parameters. Lower or smaller loads generally lead to less efficiency. The digital controller provides many options to optimize the efficiency of SMPS over the entire operating range or wider ranges.
During little to no load conditions the switching power supply can be programmed to low power modes by stopping the switching action, pulse skipping, shutting down a pulse width modulator (PWM) module, or even causing the microcontroller to go into a low current sleep mode until the supply is needed again.
Using a microcontroller to provide error amplification and compensation allows designers to quickly adjust the compensation and observe the results without changing component values or configurations. Different compensation arrangements can also be provided for different situations during power supply operation. Inductor current limits, output voltage, and even operating frequency can be adjusted automatically while the power supply is running in the system if desired.