Design of a Power Regulated Circuit with Multiple LDOs for SoC Applications

In this paper, a power regulated circuit (PRC) is proposed for system-on-a-chip (SoC) applications. The proposed PRC is composed of a limiter, a bandgap reference (BGR), three low-dropout regulators (LDOs), and a bias generator. A high output voltage of an active rectifier is given to the limiter, which limits it to a desired supply voltage for circuits in PRC. The curvature-compensated BGR robust to process, voltage and temperature (PVT) variations are designed to provide a stable reference voltage for three LDOs. The three LDOs are implemented to generate regulated output dc voltages. The proposed PRC is designed and fabricated in 130 nm bipolar-CMOS-DMOS (BCD) technology with die area of 1.9 mm × 0.860 mm, including pads. The measurement results show that the limiter limits the input voltage of (6 V to 20 V) to 5.3 V. The BGR produces a stable reference voltage of 1.24 V with a power supply rejection ratio (PSRR) of −58.6 dB and −51.9 dB at 10 Hz and 1 kHz, respectively. The LDO_5V, LDO_3V, and LDO_1.5V generate regulated output dc voltages of 5 V, 3 V, and 1.5 V, respectively, with dc load regulations of 0.43 mV/mA, 0.70 mV/mA, and 0.28 mV/mA while delivering load currents of 300 mA, 100 mA, and 100 mA, respectively.