On-chip LDO (low dropout regulator) capable of making low-voltage fast transient response

Abstract

The invention discloses an on-chip LDO (low dropout regulator) capable of making low-voltage fast transient response and belongs to the technical field of power supply management. A grid electrode of each power tube is connected with an output end of the output stage, and a drain electrode of the power tube is grounded through a series structure of a first feedback resistor and a second feedback resistor. An in-phase input end of an error amplifier is connected with the series joint of the first feedback resistor and the second feedback resistor, and an inverting input end of the error amplifier is connected with reference voltage, a first output end of the error amplifier is connected with a first input end of the output stage, and a second output end of the error amplifier is connected with a second input end of the output stage. A Miller capacitor is in series connection with a zero-setting resistor, the other end of the zero-setting resistor is connected with the grid electrode of the power tube, the other end of the Miller capacitor is connected with the drain electrode of the power tube. A load capacitor is connected between the drain electrode of the power tube and the ground. An inverter based rail-to-rail input operational amplifier is introduced to the error amplifier to achieve the purpose of low input voltage, and an STCB structure and a high-pass coupling structure are introduced to realize fast transient response of the on-chip LDO. The on-chip LDO realizes self-starting without extra bias network.

Description

Technical field [0001] The invention belongs to the technical field of power management, and specifically relates to an on-chip low-dropout linear regulator LDO with low voltage and fast transient response. Background technique [0002] With the rapid development of electronic products such as mobile phones and palmtop computers and integrated circuit systems, power management chips have shown an increasingly important role in the field of integrated circuits. Low Dropout Regulator (LDO), as a member of the DC power management chip, has the characteristics of low cost, low noise, high precision, and simple peripheral circuits, and is widely used in various electronic products. Compared with the traditional output LDO with large capacitance, the on-chip LDO is easier to integrate. However, due to its small output capacitance, the undershoot of the output voltage during load switching will be significantly larger than that of a traditional LDO with a large capacitance. It is diffi...

AI Technical Summary

Problems solved by technology

[0010] Aiming at the disadvantages of poor transient response performance of the existing on-chip LDO and difficulty in application under low power supply voltage, the present invention provides an on-chip LDO with low-voltage fast transient response, by introducing an inverter-based rail-to-rail into the error amplifier Rail input operational amplifier achieves the purpose of low input voltage, the introduction of STCB structure and high-pass coupling structure realizes the fast transient response of the on-chip LDO, and does not need an external bias network, the LDO can achieve self-start

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