A 310 nA DCM Hysteretic Buck Converter With 95.8% Peak Efficiency and Greater Than 90% Efficiency in 10 <i>μ</i> A–100 mA Load Range for Battery Powered IoT Sensors

This paper presents a discontinuous conduction mode (DCM) hysteretic buck converter for battery-powered Internet of Things (IoT) sensors. To reduce the quiescent power consumption, a duty-cycled comparator with delay compensation feedback loop is used in the zero current detector (ZCD). This feedback loop generates a self-calibrated comparator input offset to compensate for the comparator propagation delay. Additionally, a dynamic biasing scheme is applied to the hysteretic comparator to enhance the conversion efficiency under light load. The proposed buck converter was implemented in a 55-nm CMOS BCDLite process with an active area of 0.76mm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ \times 0.69$</tex-math> </inline-formula> mm. With 310 nA quiescent current, this buck converter supports load currents in the range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~{\mu }$</tex-math> </inline-formula>A - 300 mA with output voltage 0.8 V - 2.2 V. In particular, greater than 90% efficiency is maintained for load current from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10~{\mu }$</tex-math> </inline-formula>A to 100 mA with 95.8% peak efficiency.