The invention relates to a self-adaptive digital DC /
DC control method which has fast dynamic response and a converter. The self-
adaptive control method related by the invention is implemented in a
secondary side controller. In the control method, error detected is positive (negative) when sag (uprush) happens to an output
voltage, and a first PID with good steady-state characteristics is switched to a second PID with good dynamic characteristics when the absolute value of the error exceeds a preset threshold value, the output
voltage begins to enter a
steady state when the error turns to be negative (positive), and the second PID is switched to the first PID when alternative changes between positive and negative errors are continuously detected, for which a
steady state is deemed to be realized. The circuit structure of the DC /
DC converter comprises a main
power topology, an isolating
transformer, a primary side controller, the
secondary side controller, a
driving circuit, a
voltage and current detecting channel, a feedback and sampling channel, a primary side assisting source, a
secondary side assisting source, a parameter memorizer and a
communication interface. The control method of the invention has reasonable design and the converter is simple and practical.