Power switching module of digital-analog hybrid circuit reference source

Abstract

The invention discloses a power switching module of a digital-analog hybrid circuit reference source. One input end of the power switching module is connected into an external power supply, the output end of the power switching module is connected with the input end of the band-gap reference source, the output end of the band-gap reference source is connected with the input end of a low drop-out linear voltage stabilization source, the output end of the low drop-out linear voltage stabilization source is connected into the other input end of the power switching module in a feedback mode, the band-gap reference source and the low drop-out linear voltage stabilization source can provide enable signals respectively for the power switching module to enable the power switching module to switch over the power supply mode after logical judgment, and the voltage of the external power supply or the voltage of the drop-out linear voltage stabilization source can be provided for the band-gap reference source. According to the power switching module of the digital-analog hybrid circuit reference source, power line and ground electrode interference can be reduced, or the high power voltage rejection ratio is achieved, or working stability is improved, or the load regulation rate is optimized.

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 being used more and more widely. Because there are digital circuits and analog circuits at the same time, many factors must be considered when designing. Here are 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 to the analog circuit and will affect the performance of the analog circuit. Since most of the interference sources are generated by the ground wire and the power wire, and the noise caused by the ground wire is the largest, the design of the ground wire and the power wire is very important in...

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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