Design Of A Low Power Consumption Boost DC-DC Converter

With the requirements of miniaturization,low cost and high efficiency of electronic equipment.In particular,the growth of IOT devices will require booster chips to power sensors or communication modules in many scenarios,such as dry battery and button battery power applications.The traditional BOOST has a large static power consumption,which is usually above 10 u A.The BOOST chip is only turned on when the sensor and communication module are working,often leads to signal detection delay.In this paper,a BOOST DC-DC converter with a static power consumption as low as2.5 u A is designed,and it can work normally under low power supply voltage.It has three working modes: CCM,DCM,and burst mode.This chip adopts hysteresis current mode control.By sampling the inductor current in a full cycle,a sawtooth wave signal is obtained,Then enters the hysteresis comparator to obtain a square wave control power level to adjust the output voltage;the hysteresis current mode does not require a slope compensation circuit and does not need oscillation,and is suitable for low power consumption design.The chip adopts synchronous rectification technology,and has designed a start-up oscillator and charge pump to ensure low-voltage start-up capability;according to different loads,it can switch between CCM,DCM and burst mode.This paper proposes a simple structure to achieve burst mode,by detecting the output voltage of the error amplifier to switch the working phase and the non-working phase.When the load current is low,the B-EN pin can make the chip enter the burst mode or maintain the DCM mode to obtain higher efficiency or lower ripple.Burst mode can provide a load current of up to 20 m A;in burst mode,most of the modules in the chip are turned off,and the load current is supplied by the output capacitor.When the voltage drops to the set threshold,Then charge the output voltage through hysteresis current mode.In Burst mode,the ripple is about 30～80 m V,and the quiescent current is as low as 2.5 u A.The power-on and shutdown process is completed by the built-in burst mode control circuit,which detects the output signal of the EA comparator to realize the control of the chip;the designed of burst mode circuit has a simple structure and low system power consumption.Based on the GSMC＿L018S4G9 process,the chip is simulated and analyzed.After simulation verification,this chip has a wide input voltage range of 1.2～4.5 V,an output voltage range of 2.4～5.5 V,static power consumption as low as 2.5 u A,maximum inductor current of 1 A,and output voltage ripple of about 10 m V in CCM mode,The conversion efficiency under 20 u A can reach 80.78%,and the conversion efficiency under 100 m A can reach 94.13%,which can meet the requirements of various batterypowered small electronic systems.