The Analysis and Design of Dual Buck Switching Mode Power Supply
|School||Xi'an University of Science and Technology|
|Course||Power Electronics and Power Drives|
|Keywords||DC voltage converter Pulse width modulation Pulse Frequency Modulation High efficiency Low power consumption|
With the growing popularity of portable electronic products , the DC voltage converter (DC-DC) chips are widely used. These products typically use a single battery-powered , energy limited , how to improve the conversion efficiency , reduce power consumption and extend battery life, and became a designer needs to consider the main problem . This graduation project proposed based on pulse width modulation (PWM) and pulse frequency modulation (PFM) mode , high- efficiency , low-power switching power supply DC voltage converter design method . Circuit load current is small (about lt ; 70mA ) load current (about gt; 70mA ) , the inductor current is continuous , the switching frequency of 2MHz Voltage PWM control operating modes ; discontinuous inductor current , a more small , the switching frequency of the peak current and voltage dual control of the PFM operating mode, to achieve a high conversion efficiency in the load current changes the range of 0 ~ 500mA . Chip using SMIC 0.35μm CMOS mixed-signal model design . The simulation and test results show that the circuit can realize a smooth transition between PWM and PFM mode power supply , as well as two modes , and has a better ability to load and linear regulator . Output voltage error of less than 4% of the soil , the maximum quiescent operating current of less than 18μA, maximum conversion efficiency of 90% . The paper first and second chapters discuss the switching power supply DC-DC regulator principle and control methods . The third chapter describes the system structure and the operating mode of the graduation design of the DC-DC converter . Chapter IV Intro design idea of the main circuit of the DC-DC converter module . Chapter 5 gives the the BUCK system simulation results .