A Low-Power High Accuracy Over Current Protection Circuit for Low Dropout Regulator

Socheat HENG  Cong-Kha PHAM  

IEICE TRANSACTIONS on Electronics   Vol.E92-C   No.9   pp.1208-1214
Publication Date: 2009/09/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E92.C.1208
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electronic Circuits
over current protection,  limiting current,  holding current,  low dropout regulator,  low power,  low voltage,  

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In this paper, a low power current protection circuit implemented in a low dropout regulator (LDO) is presented. The proposed circuit, designed in a 0.35 µm CMOS process, provides a precise limiting current as well as holding current with low dependency on both supply voltage and regulator output voltage. The experimental results showed that the proposed circuit is operable in the regulator output voltage range from VOUT=1.2 V to VOUT=3.6 V and supply voltage range from VDD=VOUT+0.5 V to VDD=5.6 V. Since the proposed circuit is composed of few simple basic circuits such as a comparator and a Schmitt Trigger, it has a low current consumption of less than ISS=0.82 µA at a load current of ILOAD=200 mA. This makes the circuit suitable for low power and low voltage LDO design.