High Performance Ultra-low Quiescent Current LDO Regulator

Abstract

This paper deals with the design of a high performance ultra-low quiescent current LDO voltage regulator in BCD technology of STMicroelectronics company. Efficiency is one of the most important aspects of contemporary integratedcircuits. Therefore,besidestheultra-lowquiescent current around 1 microampere under no load current condition, the emphasis has been put on ultra-low drop-out voltage as well. Although there are available ultra-low quiescent current LDOs on the market with a quiescent current in units of microamperes, some of their parameters are not usually sufficiently good, for example, power supply rejectionratio(PSRR)andtransientresponsebehavior. Thementionedultra-lowdrop-outvoltageisnotgenerallytheirboast featureeither. TheproposedLDOrepresentsauniquedevice comparing to commercial products regarding the mentioned parameters. Another key feature of this device is the ability to function even with as low input voltage as 0.8 volts. This isallowedbyusinganNMOSpowertransistorwhilethevast majority of commercial LDOs uses PMOS transistors which normally do not allow that low input voltage