Design Of An Adjustable, Low Voltage Low Dropout Linear Regulator

The power management IC (integrated circuit) has many advantages, such as high integrity, high performance/price ratio, the simplest peripheral circuit, the best capability, and high-eficiency power supply etc. It has the vast market foreground. The circuit designed in this paper is for a low power CODEC system. The general applications include the PDA, MP3, DC, radiotelephony and the network of database, instrument etc. Currently many foreign companies still occupy most market of power management IC. It is important to study and develop domestic power management IC product.The object of this paper is to design a low dropout voltage (LDO) linear buck regulator. It has the wide input voltage range (1.6V～3.6V) and seven different output voltages (2.0V, 1.9V, 1.8V, 1.7V, 1.6V, 1.5V, 1.4V). When the load current is 50 mA, the dropout voltage is only 100 mV. This circuit is primarily used as power supply of the circuit such as CPU, DSP etc. In addition, the overheating protection circuit is also designed, which guarantees the electric circuit working in safe operation area (SOA). Based on above technical advantages, the monolithic power supply management ic chip posses excellent characteristics of high efficiency and low power with simple peripheral circuit, the cost is reduced dramatically, the system is powerful for load adjustment, the chip can operates stably under various conditions.The low dropout regulator is designed in SMIC 0.18um CMOS process and is simulated using the EDA softwares, such as Cadence and Hspice. The pre-simulation and post-simulation verification are performed for the chip circuit under different models, voltages, temperatures, this enhances the design reliability and fab success. The simulation results show that the performance and characteristics of the chip are excellent and it can perform diverse pre-specific functions and meet the specifications.