Low dropout linear voltage regulator with large output current range

Abstract

The invention relates to a low dropout linear voltage regulator with a large output current range, and belongs to the field of integrated circuit design. After output voltage of an LDO (Low Dropout Regulator) is subjected to voltage division sampling, feedback voltage is obtained; the feedback voltage and reference voltage are input into an error amplifier; after being amplified, a voltage difference is supplied to a controller realized by a digital circuit; the controller outputs a control word to adjust on and off of current of each branch, so that the LDO can output stable current; each branch is formed by connecting a switch tube with a current source in series; all the branches are connected in parallel and are connected between a power supply and the output voltage; particularly, the controller converts an input analog signal into a digital signal through a digital-to-analog converter and then processes the digital signal through a digital logic control circuit to obtain the control word, so as to control on and off of multiple current branches consisting of the current sources and switches, and obtain required output current. The multiple parallel-connected current branches supply the output current, so that the low dropout linear voltage regulator is relatively large in output voltage range; each branch comprises the current source and the switch which are connected in series; the output current is stable.

Description

Technical field [0001] The invention belongs to the technical field of integrated circuit design, and in particular relates to a low-dropout linear regulator with a large output current range. Background technique [0002] Low Dropout Regulator (LDO) has the advantages of small input and output voltage difference, stable output voltage, low noise, etc., and has a wide range of applications in integrated circuits. [0003] figure 1 It is a schematic diagram of a classic analog low dropout linear regulator. V OUT It is the output voltage of the LDO, which remains stable under the action of the feedback loop. When load R L , C L When changing, the control voltage V output by the error amplifier C Along with change, control adjustment tube M 1 The output current is for the load. When the LDO is in a light load state, the regulator tube M 1 The output current needs to be small; when the LDO is under heavy load, the regulator M 1 The output current needs to be large. However, for a s...

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Problems solved by technology

In this circuit, the MOS tube M S1 ~ M SN When turned on, it provides current as a current source, but its output current is easily disturbed by the power supply voltage and control voltage, making the output current of the LDO inaccurate

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