How to correctly select the power module, analog power supply, switching power supply, digital power supply difference analysis

How do we choose the power module in the power design, then the premise of the choice is that we have to understand all kinds of power supply, understand the difference between all kinds of power supply, so that we can correctly choose the power module.
How do we choose the power module in the power design, then the premise of the choice is that we have to understand all kinds of power supply, understand the difference between all kinds of power supply, so that we can correctly choose the power module.

Analog power supply: transformer power supply, through the core, coil to achieve, the number of turns of the coil determines the voltage ratio between the two ends, the role of the iron core is to transfer the magnetic field change, (China) the main coil at 50HZ frequency produced a change in the magnetic field, the change of the magnetic field through the core to the secondary coil, in the secondary coil produced Induction voltage, so the transformer will achieve a voltage change.
The disadvantage of analog power supply: coils and iron cores are conductors themselves, so they will heat up (loss) due to self-inductance current in the process of transforming voltage, so the transformer efficiency is very low, generally not more than 35%.
Application of transformer in audio amplifier: High power amplifier needs transformer to provide more power output, then, only through the increase of coil turns and core volume, the increase of turns and core volume will aggravate its loss, so the transformer of high power amplifier must do very big, this It can lead to heavy weight and high calorific value.
Introduction of switching power supply
Switching Power Supply: Before the current enters the transformer, the current frequency of our usual 50HZ is raised to tens of thousands of HZ by the switching function of the transistor. At such a high frequency, the frequency of the magnetic field changes to tens of thousands of HZ, so that the number of coil turns and the volume of the core can be reduced and the same voltage conversion ratio can be obtained because of the wire. With the reduction of the number of turns and the volume of the core, the loss is greatly reduced. The efficiency of the general switching power supply reaches 90%, and the volume can be done very small, and the output is stable. Therefore, the switching power supply has the advantages that analog power supply is difficult to achieve.
(Switching power supply also has its own shortcomings, such as output voltage ripple and switching noise, linear power supply is not)
Application of switching power supply in audio equipment-power amplifier: The advantages of switching power supply have been shown in the description process of switching power supply, so even for high-power amplifier, switching power supply can be done very fine and compact. At present, the domestic digital power amplifier is the most advanced digital power amplifier in Shenzhen Tripas Digital Audio Equipment Company. They have now developed to class T pure digital power amplifiers, and the next generation of class S power amplifiers are also under development, see the following specific information:
Introduction of digital power supply
Analog power supply products have more advantages in simple and easy-to-use applications where few parameters are required to be changed, because the specificity of their applications can be achieved by hardware solidification, while digital power is used in complex high-performance systems with more controllable factors, faster real-time response, power management of multiple analog systems, and more complex requirements for power management. The source has advantages. In addition, in the complex multi-system business, compared with analog power supply, digital power is programmed by software to achieve a variety of applications, its scalability and reusability allows users to easily change working parameters and optimize the power system. Through real-time overcurrent protection and management, it can also reduce the number of peripherals.
In the complex multi-system business, compared with analog power supply, digital power supply implements many applications through software programming. Its scalability and reusability make it easy for users to change working parameters and optimize the power system. Through real-time overcurrent protection and management, it can also reduce the number of peripherals.
Digital power is useful for DSP control and MCU control. Relatively speaking, the power supply controlled by DSP adopts digital filtering mode, which can meet more complex power demand, faster real-time response speed and better power stabilization performance than the power supply controlled by MCU.
What is the advantage of digital power is that it is programmable in the first place, such as communication, detection, telemetry and all other functions can be programmed by software. In addition, the digital power supply has high performance and high reliability, and is very flexible.
Interference: between digital and analog signals in a single chip microcomputer, because digital signals are pulse signals with a wide spectrum, the interference of the analog part is very strong; not only are digital and analog power sources generally used to separate, the two are connected by filters, in some high-demand occasions, such as some monolithic When the AD converter in the machine is converted to AD, the digital part is often put to sleep, and most of the digital logic stops working to prevent them from interfering with the analog part. If the interference is serious, you can even use two power sources separately, usually isolated by inductance and capacitance. You can also connect the digital and analog parts of the whole board together, and connect them directly to the solder joint of the filter capacitor of the power supply through separate channels. Get up.
If you do not use the A/D or D/A function of the chip, you can not distinguish between the digital power supply and the analog power supply. If A/D or D/A is used, reference power design is also necessary.