Improved mixed-signal chip

Abstract

The invention discloses an improved mixed-signal chip. In the improved mixed-signal chip, the reference voltage source of a power supply circuit comprises a power supply switch module, a bandgap reference voltage source and a low dropout linear regulator source, wherein one input end of the power supply switch module is connected into an external power supply; the output end of the power supply switch module is connected with the input end of the bandgap reference voltage source; the output end of the bandgap reference voltage source is connected with the input end of the low dropout linear regulator source; the output end of the low dropout linear regulator source is connected into the other input end of the power supply switch module in a feedback manner; the bandgap reference voltage source comprises a bandgap reference voltage source unit, a starting unit of the bandgap reference voltage source and the amplifier unit of the bandgap reference voltage source; the starting unit of the bandgap reference voltage source can enable the bandgap reference voltage source unit to conduct auto start; the amplifying unit of the bandgap reference voltage source can enable the two input node levels of the bandgap reference voltage source unit to be kept equal. According to the invention, properties in a certain aspect of reducing interferences of the power cord and the ground wire, or realizing high power supply voltage rejection ratio or improving working stability or optimizing load regulation are improved.

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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