关键词: 降压转换器, 超低静态电流, 自适应恒定导通时间, 轻载高效率

Abstract: In the applications such as wearable and internet of things (IOT), the system is usually powered by batteries. In order to ensure a long standby time, the power supply chip is required to have an ultra-low standby current. In order to reduce standby power consumption, most circuits turn off in sleep mode with no load, and only low power oscillator (LP_OSC), voltage reference sample &hold and low power comparator (LP_CMP) work, so the standby current is merely 430 nA. Meanwhile, in order to ensure good transient performance, an adaptive constant on time (ACOT) structure is designed. This structure has the characteristics of good transient performance, stable frequency in current continuous mode and stable loop. The chip can deliver as much as 600 mA current for output,the peak efficiency is up to 96%. With 5V input voltage, 3.3 V output voltage and 10 μA current load, the efficiency is higher than 80%.

Key words: step down converter, ultra-low quiescent current, adaptive constant on time, high efficiency with light load