Design of high-reliability LDO regulator with SCR based ESD protection circuit using body technique and load transient detection

Abstract

External capacitors in conventional LDO regulators can reduce transient response characteristics such as overshoot and undershoot. However, the capacitor-less LDO regulator proposed in this study achieves the transient response improved by applying body technique to the pass transistor, thereby provides the high areal efficiency and excellent current driving capability, and shows the improved ESD robustness characteristics. Also, the proposed ESD protection device based on due to the SCR (Silicon Control Rectifier) built into the output node and the power line. As a result, it was confirmed that the transient response characteristics of the proposed LDO regulator were improved and free space could be secured by applying the body technique of the pass transistor. The operating conditions of the proposed LDO regulator were set as an input voltage varying from 3.3V to 4.5V, a maximum load current of 200mA, and the output voltage of 3V. As a result of the measurement, when the load current was 200mA, the voltage was found to be 23mV in the undershoot state and 29mV in the overshoot state. In addition, the ESD robustness characteristic of HBM is secured at 8kV or higher.