| The motivation behind the study of low drop-out(LDO) regulators is driven by the increasing demand for higher performance power supply circuits. Nowadays, foreign enterprises almost occupy the whole market of power management IC. So it is necessary to dominate such a big market. Therefore, it is of great significance to research and develop domestic power management IC. Moreover, it is very important to study the LDO linear regulator circuit. The typical application of the chip includes the Mobile phones,Wireless communication equipment, PDA, portable AV equipment, Battery powered equipment.In this paper, an error Amplifier applied to a low dropout voltage (LDO) linear voltage regulator has been designed. The chip is manufactured by 0.5un, 2P3M, CMOS process. The output voltage of the whole LDO chip is 3.05 V. When the load current of LDO is 30 mA, the dropout voltage of LDO is only 60 mV. What's more, besides the basic block, the LDO linear voltage regulator also includes current limit block, which guarantee the LDO chip operating in safe operation area. LDO regulator with this AMP as error amplifier is highly precise, low noise, positive voltage LDO regulators.In the first part, this paper introduces the background and significance of this research. In the second chapter, firstly the basic theory of LDO linear voltage regulator is narrated. And then, the general structure of the LDO linear voltage regulator is discussed based on its function requirement. Thirdly, There is a detailed description about the amp design. After that, On the basis of the prior knowledge, We design an error amplifier, which has been applied into the LDO linear voltage regulator successfully. With the software HSPICE, simulations of the error amplifier are in good agreement with the theoretical analysis. Therefore, the results have shown that because of this cascade amplifier, the LDO linear voltage regulator has realized its functional object and numeric object successfully. |
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