Low-dropout linear regulator of improved digital-analog hybrid circuit

Abstract

The invention discloses a low-dropout linear regulator of an improved digital-analog hybrid circuit. The digital-analog hybrid circuit comprises a power circuit, an analog circuit and a digital circuit which are integrated on a PCB. The digital circuit and the analog circuit are physically isolated. An analog circuit ground and a digital circuit ground are separately arranged in different stratums. The low-dropout linear regulator comprises an error amplifying circuit, a power level output circuit and a bandwidth increasing circuit. The output end of the power level output circuit is connected to the positive-phase input end of the error amplifying circuit in a negative feedback mode. The negative-phase input end of the error amplifying circuit is connected with a reference voltage. The output end of the bandwidth increasing circuit is connected with the input end of the power level output circuit, and the bandwidth increasing circuit is used as a second level non-inverting amplifier for increasing the bandwidth of the whole negative feedback loop circuit. The low-dropout linear regulator can improve one of the functions of reducing interference between a power line and an earth wire, achieving the high supply voltage rejection ratio, improving work stability and optimizing load regulation.

Description

technical field [0001] The invention relates to integrated circuit design technology, in particular to a digital-analog hybrid circuit (chip) and its auxiliary circuits. Background technique [0002] At present, digital-analog hybrid circuits are more and more widely used. Due to the existence of digital circuits and analog circuits at the same time, many factors must be considered during design. Here are some examples: [0003] One is that the grounding should be reasonable. In the digital-analog hybrid circuit, the digital signal is a noise source of the analog signal, which will bring ground bounce noise and power disturbance to the entire circuit. These noises and interferences are coupled into the analog circuit, which will affect the working performance of the analog circuit. Since most of the interference sources are generated through the ground wire and the power wire, and the noise interference caused by the ground wire is the largest, the design of the ground wi...

AI Technical Summary

Problems solved by technology

The traditional bandgap reference source needs to use the feedback loop formed by the operational amplifier to realize the stable output of the voltage reference source. Due to the limitation of the bandwidth and gain of the operational amplifier itself, the fluctuation of the power supply voltage cannot be achieved within a certain bandwidth range (especially in the middle frequency band). is well suppressed, thereby affecting the output signal quality of the reference voltage source

In addition, in the traditional bandgap reference circuit, the output voltage VBE is about 1.25V, which limits the application of the power supply voltage below 1V

The subsequent improved enhanced bandgap reference source circuit structure uses a pre-voltage source to supply power to the bandgap reference source alone, which improves the power supply voltage rejection ratio to a certain extent, but the improved circuit structure increases static power consumption and chip area.

[0005] In addition, there are other deficiencies in existing digital-analog hybrid circuits, which need to be optimized to improve performance

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