A Single-Event Transient Tolerant Multi-Loop Hybrid Low-Dropout Regulator in 28-nm CMOS Technology

Low-dropout regulators (LDOs) are critical modules in aerospace electronic systems. However, they are susceptible to single-event transient effects, which can impact the stability of the power system. Currently, almost all aerospace LDOs employ analog design to achieve robust output current characteristics. In this paper, three LDO architectures including analog LDO, digital LDO, and hybrid LDO are investigated, and a novel multi-loop hybrid LDO featuring analog proportional and digital integral control is proposed. A load detection module is introduced to allow the analog loop to operate independently under light-load conditions, thereby eliminating limit cycle oscillation (LCO) issues. In addition, a falling edge detection module is implemented to accelerate the transient response of the circuit. Three LDO circuits are designed using a 28 nm CMOS process, and their single-event transient responses are compared using double-exponential current pulse simulations. The results show that the proposed hybrid LDO exhibits the strongest transient response and best immunity to single-event effects under heavy-load conditions, achieving an efficiency of 99.975%.