A Low Dropout Linear Regulator with High Power Supply Rejection Ratio and Fast Transient Response

Abstract

The invention discloses a low-dropout linear regulator with high power supply rejection ratio and fast transient response, and the invention belongs to the field of low-dropout linear regulator LDO. The low-dropout linear voltage regulator circuit with high power supply rejection ratio and fast transient response proposed by the present invention will cause Vout to change (ΔVout) when the load current changes instantaneously. After the negative feedback path composed of tubes, it is added to the output terminal with an amount opposite to ΔVout, so that Vout is finally stable near the value of Vref. The folded cascode structure is used as the error amplifier, which has the advantages of large gain and large input voltage range. The negative input terminal of the unity gain buffer circuit is connected to the output terminal, and its closed-loop gain is 1, which isolates the large resistance and large capacitance to meet the phase requirements and improve the transient response characteristics. The first intermediate capacitor is used to improve transient response characteristics and circuit stability, and the dynamic bias structure is used to improve transient response characteristics and power supply rejection ratio.

Description

technical field [0001] The invention belongs to the field of LDO (Low drop-out linear regulator). Background technique [0002] In recent years, with the development of mobile consumer electronics, in order to reduce costs and improve efficiency, analog, digital, and RF modules are often integrated on the same chip. The digital and RF modules in these modules are very sensitive to noise. If a A clean and stable supply voltage will affect the performance of these modules. Low-dropout linear regulator LDO has the advantages of low cost, high efficiency, small output ripple, and small quiescent current. It is often used in the power management part of the chip, and its power supply rejection ratio (Power Supply Rejection Ratio, PSRR) is improved. Stable work of sensitive modules. The literature [Zhang Qi. Design of low-power LDO linear regulator with high power supply rejection ratio [D]. Xidian University, 2018.] proposes a scheme to improve the power supply rejection ratio ...

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Problems solved by technology

However, this structure needs to add multiple branches, resulting in high static power consumption, and there is still a lot of room for improvement in terms of phase margin and bandwidth

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