A High-Efficient DC-DC Buck Converter with Adaptive Constant On-Time Control

This paper presents a DC-DC Buck converter featuring an adaptive constant on-time (ACOT) control technique, designed to maintain high efficiency across a wide load range for Internet of Things (IoT) applications. The converter utilizes a voltage feedback loop to maintain a stable 3.3V output voltage and ensure fast transient response. Additionally, a current-sensor-based feedback loop detects load changes to maintain system stability and efficiency. The ACOT control block dynamically adjusts between modes to optimize efficiency under varying load conditions. Implemented in 0.18 μm BCD technology, the proposed converter occupies 0.63 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of silicon area. Operating with a nominal 5V input, it supports an output load current range of 10 μA to 2A, maintaining efficiencies above 90% and achieving a peak efficiency of 97% at a 500kHz switching frequency. With automatic mode transitions, output ripple remains below 20mV under a 5V input, ensuring performance stability across operating conditions.