| At present, the DC-DC converter is an important part of someelectronic systems. It is the basis of the circuit working properly.TheDC-DC converter has been widely used in communications、IT、comsumer electronics products due to its small size、light weight、highefficiency、wide-range output voltage.In recent years, the portable electronic products is becomingmore and more popular, which makes a rapid growth of powermanagement IC. With the purpose of providing more functions and highperformance, such as saving energy, these electronic products needswitching power supply chip with high conversion efficiency.This thesis proposes a high-efficiency and high-integrationDC-DC converter to meet the application requirement of portableelectronic prodcuts. The chip adopts synchronous rectificationtechnology and Buck PWM control mode. The chip designs a NMOS power switch and designs a bootstrapped circuit to increase the gatevoltage. In addition, the thesis also designs adecreasing-frequency-protection circuit, as well as soft-start andprotection circuits. The simulation results show that the DC-DCconverter can meet the high-efficiency requirement..Each block and the whole system have been simulated usingSpectre with the model of HHNEC0.35um BCD process. It covers thevoltage range from4V to8.5V and provides the output voltage from1.8V to5V with a maximal output current of1A. The simulationindicates that the power efficiency is above90%with5V supply voltage,3.3V output voltage and5load resistor. the output ripple is only2mV.The capacity of linear adjustment and load regulation is also pretty good. |
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