A digital linear regulator

Abstract

The invention provides a digital linear voltage regulator, comprising a band-gap reference source, a clock signal generation module, a comparator, an regulation tube selection and control circuit, a regulation tube circuit, and a feedback voltage. The clock signal generation module generates a clock signal CLK and respectively provides the clock signal for the comparator and the regulation tube selection and control circuit; and the band-gap reference source generates a reference voltage VBG. The feedback circuit receives an output voltage Vout of the digital linear voltage regulator and outputs a feedback voltage VFB to the comparator. The comparator compares the feedback voltage VFB with the reference voltage VBG on a rising edge or a falling edge of each clock signal CLK, and outputs acomparison result to the regulation tube selection and control circuit. The regulation tube selection and control circuit determines a digital control code according to the comparison result, whereinthe digital control code is used for controlling the number of opened regulation tubes in the regulation tube circuit. The feedback voltage VFB or the reference voltage VBG is regulated with the change of the digital control code.

Description

technical field [0001] The present invention relates to voltage regulators, and more particularly to digital linear voltage regulators. Background technique [0002] The main function of the linear voltage regulator circuit is to provide a stable low-noise power supply to the internal modules of the system. The linear voltage regulator circuit is an essential and important circuit module of the microcontroller (MCU) system, and is widely used in the fields of analog integrated circuits and digital-analog hybrid integrated circuits. [0003] figure 1 A schematic diagram showing the architecture of a conventional digital linear regulator. [0004] Such as figure 1 As shown, the traditional digital linear regulator circuit is composed of a comparator, a digital logic control module and a switch array regulator tube. When the load current changes, the logic control module realizes the voltage stabilizing function by controlling the opening quantity of the regulating tube. T...

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Problems solved by technology

Therefore, when the digital linear regulator fixes the voltage of the reference voltage VBG at a unique level, it means that the circuit load regulation is extremely small, that is, the feedback loop gain is extremely high, and it is easy to occur at this time figure 2 Oscillating problems shown

[0006] combine figure 2 , the oscillation problem is detailed as follows: When the output voltage V out above the reference level V BG When , the digital control code (Digital code) will drop, reducing the number of adjustment tubes to reduce the V out , when V out When it reaches VH, the output starts to show a downward trend. At this time, the digital control code code1 is already a stable control code. However, due to the problem of circuit response speed, V out remains above V BG state, so the control code will continue to decline, reduce the number of adjustment tubes until V out down to V BG , but at this time the control code is far lower than code1, and the number of open adjustment tubes is not enough to provide the load current i out , so that V out will continue to fall below V BG , causing the control code to start rising, the same as falling, when V out When it drops to VL, the output level begins to show an upward trend, and the control code code2 is a stable control code, but due to V out still below V BG , so the control code will continue to rise

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