Multiple-loop design technique for high-performance low dropout regulator

In portable mobile devices, the power management IC unit (PMIC) requires many low-dropout voltage regulators (LDO) with different output voltages and load current capacities to support many applications; such as Application Processor (AP), Camera, Memory, RFIC Transceivers, USB, etc. For example, the PMIC in mobile phone Galaxy S6/S7 needs more than 50 LDOs to support the above applications, which require an extremely big quiescent current that degrade battery life time. Reducing quiescent current of LDO while maintaining system's operation is critical; however, there is a big trade-off between quiescent current and other LDO's characteristics such as undershoot/overshoot, PSRR, noise, etc. This paper proposed a new multiple-loop design technique for LDO that offer very low quiescent current (more than 50% reduction); however, excellent performance improvement compared to prior reported works. The design has been successfully implemented in many products of Samsung for mobile phone, Table PCs, etc.