A digital controller with a low-power approach for point-of-load synchronous buck converters is discussed and compared with its analog counterpart to confirm its feasibility for system integration. The tri-mode digital controller IC in 0.35 μm CMOS process is presented to demonstrate solutions that include a PID, quarter PID, and robust RST compensators. These compensators address the steady-state, stand-by, and transient modes according to the system operating point. An idle-tone free condition