“I believe that everyone has more or less contact with digital power supply or analog power supply, so do you know the difference between the two? Digital circuits work in the on-off state, which seriously interferes with the power supply voltage. In complex circuits, digital circuits and analog circuits use For different regulated power supplies, the digital circuit and the analog circuit are wired separately, and finally a common ground.
I believe that everyone has more or less contact with digital power supply or analog power supply, so do you know the difference between the two? Digital circuits work in the on-off state, which seriously interferes with the power supply voltage. In complex circuits, digital circuits and analog circuits use For different regulated power supplies, the digital circuit and the analog circuit are wired separately, and finally a common ground.
The title picture is a low-power circuit powered by a USB interface, so it is not necessarily powered separately. The picture on the left has only one power supply label, and it is not possible to determine whether the circuit contains two parts of digital and analog circuits.
The picture on the right is a public power supply. The LC filter is used to isolate power supplies with different functions. Obviously, the circuit has digital power and analog power, but there is no independent power supply, and the anti-interference ability is poor.
When designing a circuit, attention should be paid to suppressing interference at the source. Use the shortest path to weld high-frequency filter capacitors, such as CC1 high-frequency ceramic capacitors, between the power supply and ground of each digital chip. Chips with high power consumption and high interference should be installed close to the power supply, and tantalum electrolytic capacitors should be used for filtering.
Analog switching power supplies have been used for decades. Its design is well known, and there are many excellent textbooks, simulation toolkits, application manuals and seminars. There are also a large number of low-cost integrated circuits provided by many manufacturers, which encapsulate many functions, from integrated gate drivers and switches to current sensing and protection.
Digital control has some characteristics that the analog world does not have, which makes the switching power supply design have functions that have not been possible until now. Think of a power supply manufacturer with many different power levels. Using digital control solutions, a single processor can work with individual custom software to meet the needs of each power level. In large-scale production, the economic scale generated will be very huge.
Analog technology + DSP/MCU has become the main trend, and the application of higher integration, faster transient response and greater flexibility into the consumer sector is the main advantage of digital power. Under normal circumstances, the analog PWM architecture can provide higher resolution, but it cannot achieve the output voltage monitoring, communication and other complex control functions that the digital control architecture has; and for the digital PWM, in order to achieve the same performance indicators as the analog control architecture, it must With high-resolution, high-speed and linear ADC, and high-resolution, high-speed PWM circuit, compared with the analog control architecture, the cost of the digital control architecture will increase significantly.
Considering the advantages of both, Maxim’s Ashrafzadeh believes that the best solution is to combine analog PWM with digital circuits to provide all the performance of digital control without sacrificing the accuracy and infinite resolution of analog control. . The above is the analysis of the difference between digital power supply and analog power supply, I hope to give you your reference.