| Portable electronic products with small size,powerful functions,high integration,were one of the important trends in the development of electronic devices.With the continuous improvement of the performance of portable electronic devices,the trade-off between the endurance of electronic devices and the volume of electronic devices has become increasingly prominent.High-efficiency power converters could effectively improve the utilization of batteries and delay the lifetime of electronic devices.Based on those,a kind of in-phase boost-buck DC-DC switching power supply conversion circuit with peak current control mode was designed for lithium batteries commonly used in portable electronic devices in this thesis.The main contents including:Firstly,on the basis of discussing the DC-DC switching power converter topology and operating principle,the modulation method and control mode of DC-DC converter were analyzed.Based on the topology of the four-switch synchronous rectification buck-boost converter,the control mode of the buck-boost converter was given in this thesis.Secondly,the boost-boost DC-DC switching power supply converter was divided into three operation modes according to the relationship between input voltage and output voltage.Analyzed the minimum duty cycle of boost mode and the maximum duty cycle of buck mode,and set the conversion voltage of the buck-boost converter.In the stability of the system loop,fixed slope compensation technology and type II compensation of transconductance amplifier technology were analyzed.Thirdly,the drain(source)-substrate PN junction between the source,drain,short gate and substrate of PMOS transistor was used to replace the base-emitter PN junction of NPN transistor in traditional bandgap reference.A low temperature coefficient of the reference voltage source was designed by adopting temperature curvature compensation technology in high temperature region and temperature piecewise linear compensation technology in low temperature region,and it achieved the temperature coefficient of 1.45ppm/°C.Finally,critical modules of the buck-boost DC-DC converter,which included the internal power supply circuit,error amplifier circuit,oscillator circuit,current detection circuit,protection circuit and drive circuit,were designed in 0.35μm BCD process.A non-inverting buck-boost DC-DC switching power supply conversion circuit with peak current control mode was designed by adopting the low temperature coefficient reference voltage source and loop compensation method.Simulation results showed that the buck-boost DC-DC switching power supply conversion had the input voltage range of 2.5V~5.5V,the switching frequency of 1.026 MHz,the average output voltage of 3.295 V,the ripple voltage of 40 mV in buck-boost mode and the maximum load current of 660 mA in each operation mode.At the same time,buck-boost DC-DC switching power supply conversion had good linear adjustment rate and transient response. |
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