A Low-power With Reverse Polarity Protection LDO Linear Regulator Design

With the advent of mobile intelligent terminals, power management chip turns out to be more and more important. Linear regulator and switching regulator has its own position in today’s market. So the research on LDO linear regulator is also very important.This paper is to design and implement low static power LDO linear regulators in the process of bipolar process. For some special systems that prone to be reversed connected of power and ground, we design reverse polarity protection circuit. We first briefly introduce some of the LDO trends, and then explain the basic theoretical knowledge of LDO linear regulator. Finally, we designed and implemented such LDO chip.In order to reduce static power, the LDO linear regulator vref module should been optimized to further reduce vref supply current and output drive current should decreases, further the process should increase output gain. All those can reduce static power consumption.In order to prevent reverse connection of power and ground, a reverse protection ciruit should be designed. In order to solve this problem, we have all the n+connected directly to the power of the forward diode, and the diode structure specially designed to increase the protection ring, which prevents parasitic current into pad to form the latch. This forms the reverse polarity protection.Put the final layout data to the foundry, and package the chip after fabrication. Actual tests show the quiescent current is400uA, and the reverse polarity protection circuit ables to stand against40V voltage.