I. Digital Power Supply
Digital power supplies mainly refer to the external characteristics of switching power supplies. These characteristics include: 1) the "communication" function of the digital power supply; 2) the "numerical control" function of the digital power supply; and 3) the function of the digital power supply in monitoring parameters such as temperature.
The characteristics of digital power supplies include:
1. Intelligent control
It is an intelligent switching power supply system with a digital signal processor (DSP) or microcontroller (MCU) at its core, and digital power drivers and PWM controllers as the controlled objects. Traditional switching power supplies controlled by microcontrollers generally only control the power supply to start and stop, and are not true digital power supplies.
2. Optimization of digital model component combination
By employing "Fusion Digital Power" technology, an optimized combination of analog and digital components is achieved in the switching power supply. For example, the analog MOSFET driver used in the power stage can be easily connected to the digital power controller to implement various protection and bias power management functions, while the PWM controller is also a digital-controlled analog chip.
3. High integration
It achieves power system on chip integration, integrating a large number of discrete components into a single chip or a group of chips.
4. High control precision
It can fully leverage the advantages of digital signal processors and microcontrollers, enabling the designed digital power supply to achieve high technical specifications. For example, its pulse width modulation (PWM) resolution can reach 150ps (10~12s), which is unmatched by traditional switching power supplies. Digital power supplies can also realize functions such as multi-phase control, nonlinear control, load current sharing, and fault prediction, providing convenient conditions for the development of green and energy-saving switching power supplies.
II. Advantages Comparison of Digital Power Supplies vs. Analog Power Supplies
Digital switching power supplies were developed to overcome the complexity of modern power supplies. They integrate digital and analog technologies, offering strong adaptability and flexibility, and the ability to directly monitor, process, and adapt to system conditions, meeting virtually any power supply requirement. Digital power supplies can also ensure continuous system reliability through remote diagnostics, enabling functions such as fault management, overvoltage (current) protection, and automatic redundancy. Due to their high integration, the system complexity does not increase excessively with the addition of functions. Fewer external components are required (the fast response capability of digital power supplies also reduces the requirements for output filter capacitors), reducing board space and simplifying the design and manufacturing process. Furthermore, the automatic diagnostic and adjustment capabilities of digital power supplies make debugging and maintenance easier. The advantages of digital power supplies over analog power supplies are mainly reflected in the following aspects:
(1) It is easy to integrate. Since digital circuits use binary, there are two types of code symbols: 0 and 1. Therefore, in a digital circuit, as long as there is a different state to represent 0 and 1 respectively, the basic unit of digital circuit is very simple and the requirements for components are not strict. It allows for greater dispersion of circuit parameters, which is conducive to integrating many basic units on the same silicon chip for mass production.
(2) It operates accurately and reliably with strong anti-interference capabilities. Digital signals are represented by 1 and 0, and it is easy for digital circuits to distinguish the presence or absence of a signal, thus greatly improving the reliability of the circuit. At the same time, digital signals are not easily affected by noise, so they have extremely strong anti-interference capabilities.
(3) Digital information is easy to preserve for a long time. Digital information can be preserved for a long time with the help of some medium (disk, optical disc, etc.).
(4) Digital integrated circuit products are numerous, versatile and low cost.
(5) It has good confidentiality. Digital information is easy to encrypt and is not easy to be stolen.
(6) It can not only perform numerical calculations, but also perform logical calculations and judgments, which is indispensable in control systems.
Digital power management chips are easily applied in multiphase parallel configurations with both multiphase and synchronous signals. They offer excellent scalability and repeatability, easily achieving load current sharing, reducing EMI, and simplifying filter circuit design. The flexibility of digital control allows power supplies to be combined into series or parallel models, forming virtual power supplies. Furthermore, the intelligence of digital power supplies ensures optimal power conversion efficiency at various input voltages and load points.
Compared to analog control technology, digital technology offers unique advantages including online programmability, more advanced control algorithms, better efficiency optimization, higher operational accuracy and reliability, and superior system management and interconnectivity. Digital power supplies do not suffer from common issues found in analog power supplies, such as errors, aging (including the precision of analog components), temperature effects, drift, and compensation problems. They require no tuning, offer high reliability, and provide consistent and stable control parameters. The computational characteristics of digital power supplies make them easier to implement advanced control algorithms such as nonlinear control (which improves the power supply's transient response) and multi-loop control; firmware updates can implement new topologies and control algorithms, and changes to power supply parameters do not require modifications to components on the circuit board.
Digital control also allows for the reuse of hardware platforms, enabling the design of different firmware to meet the unique requirements of various end systems, thereby accelerating time to market and reducing development costs, component inventory, and risks.
