Design Of Low Voltage Start BOOST DC-DC Control Chip Based On PWM Peak Current Mode

With the rapid development of the information age,portable devices such as smart phones and notebook computers are also rapidly popularized.Switching power supply,as an indispensable key module in electronic equipment,is also constantly improving.In recent years,among various portable consumer electronic products,switching power supplies have become more and more miniaturized,with lower and lower operating voltages,and higher and higher efficiency.This paper designs a BOOST DC-DC converter based on PWM peak current mode control,which is mainly used in low-power and low-current portable devices such as Internet audio players,portable medical equipment,remote controls,earphones,and mouse keyboards.Low input voltage,small output voltage ripple,low power consumption,etc.The chip designed in this paper uses synchronous rectification technology,which improves the conversion efficiency compared to the use of rectifier diodes,and uses a zerocrossing detection circuit to realize the DCM mode,and can switch between the two modes.The chip can be started at a very low voltage as low as 0.7V,and the startup is accelerated by a three-step boost method,and the output voltage is used to power the control module,thereby overcoming the problem that the control module cannot be driven by the low input voltage.The chip adopts PWM peak current mode control,constant frequency modulation ensures good frequency characteristics of the system,and the internal integrated slope compensation module enhances the stability of the system.The chip also integrates an overtemperature protection module,an over-voltage protection module,and an input undervoltage lockout module to avoid damage to the chip in harsh environments.In this paper,the circuit is simulated and tested by spectre tool of cadence software,and the circuit design is based on Hua Hong’s 0.18μm process.In order to verify the functions and performance indicators of the chip,this paper has done overall simulation and performance testing of the circuit,the results show that the switching frequency of the chip is 500 k Hz,the input voltage range is 0.7～2.3V,the load current range is 1～400m A,and the output voltage ripple is less than 10 m V,static The current is less than 65μA,the normal working temperature range is-40～110℃,the load adjustment rate is about 0.66%(1/A),the linear adjustment rate is about 0.062%(1/V),the conversion efficiency can reach more than90%.,and other performance indicators and functions also meet the design requirements.