Abstract

The output voltage transient of a buck regulator during a load current step is often a key performance specification, which is the response characteristic to a sudden load fluctuation, that is, the time until the output voltage returns to a preset value after having fallen or risen, and the waveform of the output voltage. While there are many types of control topologies addressing special design challenges for non-isolated DC/DC converter, including peak current mode control, constant on-time (COT) control, D-CAP2™ control mode (a variation of adaptive constant-on time control mode), advanced emulated current mode (AECM). The various control modes each has unique advantages. This note, we will provide a performance comparison of DC/DC converters operating in three different modes: PCM control mode, D-CAP2™ control mode (a derivative of constant on-time), and AECM control mode. These three control modes were all used widespread, none of these control modes require loop compensation which making the design simple.