The Design And Implementation Of Fully Integrated Single Inductance Dual Output Buck DC-DC Converter

With the development of technology, especially the development of miniaturized portable devices it is necessary to realize high density system routing and placement on PCB. Minimizing the number of external components is becoming one of targets when doing chip design. High efficiency DC-DC converter has been playing an important role in improving the using time of portable equipment battery technology. With the switch frequency of the converter increasing, the size of the inductance is decreased. However the most PCB space of the DC-DC converter has been dominated by the large volume inductance. A fully integrated single chip inductance used to obtain the two outputs or multiple outputs is becoming very attractive.A fully integrated single inductance dual output buck DC-DC converter is proposed in the thesis. The input voltage is 3.6V, the output voltages are 1.8V(load current 300mA) and 1.2V(load current 400mA). The voltage control mode is used in the circuit. The switch frequency is designed to be 50MHz in the thesis in order to get the fully integrated chip. The packing bonding-wire inductance is used for its high Q value and small parasitic resistance which contributes to the improvement of efficiency. The global system architecture is proposed according to the design requirements and sub-module circuits are also designed and simulated. What is more, some innovative sub-modules are proposed such as soft-start circuit and power driver circuit. Finally based on the SMIC 0.18μm CMOS process, the whole circuit is simulated by the EDA software Cadence Spectre, whose results indicate performance satisfied the requirements.