A 1.8–5.5-V LDO–BGR System With LACM Buffer for High PSRR in Camera Applications

Abstract

This brief proposes a low-dropout regulator (LDO) and bandgap reference (BGR) system designed for camera applications, where high power supply rejection ratio (PSRR) and low output noise are critical. To achieve a stable output across a wide load range from no load to 600 mA a load-adaptive current-mirror (LACM) buffer is introduced. The LACM buffer effectively regulates current flow across different load conditions, minimizing power loss while ensuring stable operation. Additionally, a sample-and-hold (S/H)-based BGR is implemented to eliminate noise propagation from the supply voltage $(V_{\mathrm { SYS}})$ to the reference voltage $(V_{\mathrm { REF}})$ , further enhancing PSRR. The proposed system was fabricated using a 0.18- $\mu $ m CMOS process.