Differences between analog power supplies, digital power supplies, and switching power supplies
How do we choose the power module in the power supply design? The premise of the choice is that we have to understand all kinds of power supplies and the differences between them, so that we can choose the power module correctly.
Introduction to Analog Power
Analog power supply: that is, transformer power supply, which is realized by iron core and coil. The number of turns of the coil determines the voltage ratio at both ends. The function of the iron core is to transmit the changing magnetic field. (my country) The main coil produces a changing magnetic field at a frequency of 50HZ. This changing magnetic field is transmitted to the secondary coil through the iron core, and an induced voltage is generated in the secondary coil, so the transformer realizes the voltage transformation.
Disadvantages of analog power supply: the coil and iron core are conductors, so they will generate heat (loss) due to self-induction current during the process of converting voltage, so the efficiency of the transformer is very low, generally not more than 35%.
The application of transformers in audio equipment power amplifiers: high-power power amplifiers require transformers to provide more power output. Then, it can only be realized by increasing the number of coil turns and the increase in iron core volume, and the increase in the number of turns and iron core volume will aggravate Its loss, so the transformer of high-power power amplifier must be made very large, which will lead to: bulky, high heat generation.
Introduction to switching power supply
Switching power supply: Before the current enters the transformer, through the switching function of the transistor, the current frequency of our usual 50HZ is increased to tens of thousands of Hz. At such a high frequency, the frequency of the magnetic field change also reaches tens of thousands of Hz, so the coil The number of turns and the volume of the iron core obtain the same voltage conversion ratio. Due to the reduction of the number of coil turns and the volume of the iron core, the loss is greatly reduced. Generally, the efficiency of switching power supply reaches 90%, and the volume can be made very small, and the output is stable, so the switch Power supplies have advantages that are difficult to achieve with analog power supplies.
(Switching power supply also has its own shortcomings, such as output voltage ripple and switching noise, linear power supply does not)
Audio equipment-Application of switching power supply in power amplifier: The advantages of switching power supply have been shown in the description process of switching power supply, so even if it is a high-power power amplifier, switching power supply can be made very fine and small.
Introduction to Digital Power
In applications that are easy to use and require few parameter changes, analog power products have more advantages, because the pertinence of their applications can be realized through hardware curing, and in applications where there are more controllable factors, faster real-time response speed, and more In complex high-performance system applications that require an analog system power management, digital power is more advantageous. In addition, in complex multi-system business, compared with analog power supply, digital power supply realizes various applications through software programming. Its scalability and reusability enable users to easily change working parameters and optimize power supply system. It also reduces the number of peripheral components through real-time overcurrent protection and management.
In complex multi-system business, compared with analog power supply, digital power supply realizes various applications through software programming. Its scalability and reusability enable users to easily change working parameters and optimize power supply system. It also reduces the number of peripheral components through real-time overcurrent protection and management.
The digital power supply is controlled by DSP and by MCU. Relatively speaking, the power supply controlled by DSP adopts digital filtering method, which can better meet the complex power supply requirements, faster real-time response speed, and better power supply voltage stabilization performance than the power supply controlled by MCU.
What are the benefits of digital power
First of all, it is programmable, and all functions such as communication, detection, and telemetry can be realized by software programming. In addition, the digital power supply has high performance and high reliability, and is very flexible.
Interference: Between digital and analog in the single-chip microcomputer, because the digital signal is a pulse signal with a wide spectrum, it is mainly the digital part that interferes strongly with the analog part; not only the digital power supply and the analog power supply are generally separated, but the two Filter connection, in some occasions with high requirements, such as when the AD converter inside some single-chip microcomputers performs AD conversion, it is often necessary to let the digital part enter a dormant state, and most of the digital logic stops working to prevent them from causing damage to the analog part. interference. If the interference is serious, you can even use two power supplies separately, and generally use inductors and capacitors to isolate them. It is also possible to connect the power supplies of the digital and analog parts on the entire board together, and use separate paths to directly connect to the solder joints of the power filter capacitors. If the anti-interference requirements are not high, they can be connected together casually.
Kind tips
(1) If the A/D or D/A function of the chip is not used, it is not necessary to distinguish between digital power and analog power.
(2) If A/D or D/A is used, the reference power supply design should also be considered.
The above are just a brief introduction to the difference between analog power supply, digital power supply and switching power supply. If you want to be an engineer, you must learn more.
