Design Of BOOST DC-DC Converter With Hysteretic-Current-Mode Control At Low Input Voltage

BOOST DC-DC converter is widely used in consumer electronic products and portable electronic equipments as an important part of Switching Mode Power Supply.With the continuous development of semiconductor integrated technology and process of the manufacturing,BOOST type DC-DC converter is also moving towards the directions of low cost,low power consumption and high efficiency.This paper designs a BOOST DC-DC converter which uses hysteresis current mode control topology with the characteristics of low input voltage,low output voltage ripple,small quiescent current,low power consumption and high efficiency,mainly used in portable consumer electronic products such as mobile phone,notebook computer,and intelligent wireless mouse.This chip adopts a novel hysteresis current mode control topology to adjust the output voltage by keeping inductor current ripple constant which makes the output voltage ripple very small.The chip dose not integrated oscillator,it dose not need the traditional slope compensation circuit to ensure the stability of the current loop because of its inherent stability,which simplifies the design of circuits.The chip uses ultra-low voltage startup technology and achieves startup at the ultra-low input voltage by using the built-in startup oscillator and charge pump,simultaneously to achieve the accelerated startup by using technology of circuit multiplexing.The synchronous rectification technology is used to reduce power consumption,and the automatic mode conversion circuit ensures that the chip can automatically convert between heavy load and light load and improves the conversion efficiency at light load.The built-in over temperature protection circuit,overload protection circuit,input undervoltage lockout circuit,overvoltage protection circuit and zero-current-detection circuit ensure that the chip can be better applied in various complex environments.On the basis of the system and key sub-module circuits,the chip is implemented by using a0.18 um BCD process and verified by Hspice of Cadence.The simulation results show that the chip can provide up to 50 m A load current and the static current is less than 10 u A and the output voltage ripple is less than 20 m V and the conversion efficiency can reach above90%.And the whole function and performance of the chip can meet the design requirements.