Design Of CMOS Low Dropout Regulator

With the popularization of mobile devices and digital products, such as notebook PC, mobile telephone, digital camera, etc, the development of corresponding integrated circuit for various battery power is more active. Since it is simple structure, cheap, low-power and smaller device size, CMOS low-dropout regulatior is widely used in portable electronic products.The reverse design of CMOS low-dropout regulatior is accomplished in the thesis. Firstly, the transverse sizes of transistors, resistances and capacitance are extracted by dissecting samples. The circuits are separated into five main modules, power control circuit , voltage reference circuit, error amplifier circuit, output transistors, short circuit protection circuit. The transistors size, resistance and capacitance value are obtained by calculating and simulating the main modules, and the optimized performance parameters of the circuit are acquired. Then, according to the dissection of the samples and the simulating results of the circuits, the possible process is given. Finally, the complete layout is provided.The main modules and the whole circuit are simulated by using the hspice software with 2μm n trap Silicon-gate process model, the simulating results show that the static current of the circuit is smaller than 80μA, the output voltage is 3V, the output current is 100mA, the dropout voltage between the input and the output is 180mV at 100mA output current, the current for the short circuit protection is 45mA, the output voltage precision is 2%.The simulating results have proved that the designed circuit has good characteristics. The circuit realized with the standard CMOS process has higher practical value.