The Design Of A Low Voltage And Practical LDO Linear Regulator

Among many power management technologies, low dropout regulator(LDO) is popular because it has such advantages as smaller area, higher power supply rejection ratio(PSRR), micro-power consumption, lower noise, and simple peripheral circuit. Besides, LDO has good linear transient response and load transient response which makes it important in portable devices, industry and auto industry. Design of LDO now becomes a research hotspot of power technology, which also has important theoretical significance and practical value of application.The main component of the LDO includes bandgap reference voltage generating module, feedback resistance network, power adjustment valve, EAMP, as well as trimming resister circuit, over temperature protection circuit module, current fold back circuit module.The drain terminal branch of power regulator add a group of trimming resistors to obtain different output voltage; we also add a hysteresis circuit to avoid oscillation phenomenon of the circuit because of temperature changes when designing the over temperature protection module. In the design of over current protection module, we take the comparison between the dropout voltage generated by the current_mirror of the power regulator and a reference voltage as the limiting control signal to realize high reliability and high stability of the LDO.The design plan is to do the system design and module function partition first; then do circuit function design and simulation; at last do backend layout design, tape-out and test.In this paper we adopt SMIC 0.5um standard process, and Spectre under cadence for simulating and verification. The simulation results show that the LDO has low power consumption, good accuracy, fast response speed, and good security.