The difference between digital power and analog power

Last Update Time: 2019-07-26 10:36:39

The digital circuit works in the switching state and has a serious interference to the power supply voltage. In the complicated circuit, the digital circuit and the analog circuit use different regulated power supplies, and the digital circuit and the analog circuit are separately routed, and finally a common ground.

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The picture is a small power circuit powered by a USB interface. It is not necessarily separately powered. The left picture shows only one power supply. It cant be judged whether the circuit contains both digital and analog circuits.

The picture on the right is a utility power supply. The LC filter is used to isolate the power supply of different functions. Obviously, the circuit has a digital power supply and an analog power supply, but there is no independent power supply and the anti-interference ability is poor.

 

Design circuit should pay attention to suppress interference at the source. Between each power supply and ground of digital chip, use the shortest path to solder high frequency filter capacitor, such as: CC1 high frequency ceramic capacitor. The chip with large power consumption and large interference should be installed close to the power supply and filtered with tantalum electrolytic capacitor.

Analog switching power supplies have been in use for decades. It is well known and has many excellent textbooks, simulation kits, application notes and seminars. There are also a large number of low-cost integrated circuits from a wide range of vendors that package a wide range of functions, from integrated gate drivers and switches to current sensing and protection.

Digital control has features that the analog world does not have, which makes switching power supply designs have features that have not been possible to date. Think of a power supply manufacturer with many different power levels. A digital control solution allows a single processor to work with separate custom software to meet the needs of each power stage. In large-scale production, the scale of the economy generated will be enormous.

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Analog technology + DSP / MCU has become the main trend, the application of the program to the consumer field penetration of higher integration, faster transient response and greater flexibility is the main advantage of digital power. In general, the analog PWM architecture can provide higher resolution, but can not achieve the output voltage monitoring, communication and other complex control functions of the digital control architecture; for digital PWM, in order to achieve the same performance indicators as the analog control architecture With high resolution, high speed and linear ADCs, as well as high resolution, high speed PWM circuitry, the cost of digital control architectures will increase significantly compared to analog control architectures. Taking into account the advantages of both, Maxim's Ashrafzadeh believes that the best solution is to combine analog PWM with digital circuitry to provide all the performance of digital control without sacrificing the precision and infinite resolution of analog control.

 

 

This article is from Allicdata Electronics Limited. Reprinted need to indicate the source.