Power supply manufacturers have recently begun to provide interfaces for controlling and monitoring power supplies. This article will focus on this reason and the prospects for circuit designers.
Let us first think about applications that require a power supply to provide high power in a short period of time. The average power required is significantly lower. Such applications may be 3D printers, laser cutting, or robotic arms that need to move quickly but stand still most of the time. Developers of these devices may prefer a power supply that can permanently provide the highest peak power expected (that is, the worst-case load current). However, using this method to determine the specifications is a very expensive power supply, the efficiency is not too good, and may lead to dangerous operation to some extent. This is because when a fault occurs, the current delivered to the load may be large enough to cause a fire.
So the answer is obvious. A smaller power supply can not only provide high power peaks in a set short period of time, but also limit the current in the event of continuous faults. The type of electrical load determines what power is required under what conditions. The developer must be consumer-oriented, allowing him to freely program the power supply. When discussing these requirements, digital interfaces are generally more popular than analog control, especially when monitoring functions are also integrated in the power supply unit. Which current should flow when? Is it feasible or the load is abnormal? Installing an appropriate smart and data bus in the power supply can easily and reliably monitor all loads connected to the power supply unit. Many modern power supplies have built-in PMBus (power management bus) that can do these tasks.
Power Management Bus (PMBus®) is an open source standard for digital energy management protocols: simple, robust and scalable. Approximately 40 PMBus member companies have adopted, promoted, and continuously improved the standard.
PMBus properties
PMBus can set one or more power supply operating parameters. For example, when a certain power supply is not needed, the power supply unit can be completely turned off, or the output voltage and current can be adjusted flexibly. The programmable fan power connector makes ordinary fans smart: fan activity and speed are automatically adjusted according to output power requirements, while reducing noise and extending the life of the fan. All functions can be achieved through standard PMBus, and there are additional benefits of the I2C protocol, so almost every microcontroller can be connected to it.
The monitoring function is as important as the PM control command set. PMBus provides real-time status data, such as input current and output current, voltage and power, temperature of key components, and detailed fault diagnosis. Based on this information, it is even possible to predict in advance before overload or overheating is about to occur. If insufficient cooling causes the internal temperature to rise, the power supply will not simply reach the temperature limit and then shut down, but will issue a warning before reaching the threshold.
In addition to simple monitoring and control, PMBus can also be directly connected to a microcontroller of the power supply to control the digital feedback loop. Therefore, it is not only to set and monitor the operating parameters, but also to modify the transient response, the conversion rate and the compensation matrix. This allows the operation of the power supply to be consistent with the actual load behavior of the application, achieving "real-time" dynamic adjustment. In short, the standard power supply will become a customized power supply after the PMBus interface is added.
RACM1200-V series power supply
RECOM’s RACM1200-V is a power supply with all the above functions. This series sets a new standard for the compactness of AC/DC power supplies and realizes a reliable fanless to support the long-term operation of the system. The design of the substrate cooling facilitates heat conduction, achieving a continuous output power of up to 1,000W, and a short-term output power of up to 1,200W. If you connect an optional fan to the fan output, the power supply can provide a continuous output of 1,200W. A variety of output voltages, constant voltage/power combinations, and hiccup mode settings make this product have a very wide range of applications, especially in terms of supporting the intrinsic safety of the application. Various analog control and monitoring functions can be operated via the connector. The other two auxiliary outputs are: a 5V to 12V programmable system fan output, and a 5V/1A isolated standby output that powers auxiliary functions and is always online. According to the needs of different projects, the RACM1200-V series can make fail-safe settings through intelligence, control and fault limiting functions. The standard version uses two signal wires and LED indicators to display the internal status:
In addition to the analog status and control pins, the PMBus version of RACM1200-V/PMB provides a digital interface for customers to directly adjust the power settings. RECOM also provides command line interface tools for power supply programming. The device can also be pre-programmed with specified firmware settings according to customer requirements.
The peak efficiency of both versions is as high as 95%, and the standby mode meets the requirements of ecological design. The RACM1200 series has obtained global safety certifications for medical (2MOPP, BF), industrial and ITE standards, as well as Class A immunity and Class B radiation requirements for electromagnetic compatibility testing. All these features make this product one of the most easily integrated modular power supplies in the industry.
RECOM company introduction
RECOM Group is a power module manufacturer originating from Germany and headquartered in Gmunden, Austria. In the past nearly half a century, it has become an innovative leader in the field of R&D and manufacturing of DC/DC converters, AC/DC power supplies, switching regulators and LED drivers. Provide a global distribution and customer support network, and products meet the highest international standards. In April 2019, RECOM acquired the Italian brand PCS. Through this acquisition, RECOM's product portfolio has been greatly extended, and it can provide a one-stop shop including AC/DC, DC/DC, AC/AC, and DC/AC inverters. The solution, the power range from below 1W to ten kW, is widely used in railway, medical, military and most industrial fields. RECOM has now become a well-known brand for high quality, integrity, innovation and quality customer service.