Before reading this article, please read Real-Time Digital Solutions for Efficient Power Supply Design (Part 1)
MPS’ HR121x series products have rich digital and analog functions. These PFC + LLC combo controllers are highly integrated and have low power consumption, making them ideal for standby power applications. They can operate in discontinuous conduction mode (DCM) or continuous conduction mode (CCM), so they can support application components under light or heavy load conditions. The digital tunability of this family of products provides a level of flexibility that easily accommodates many application requirements without the need for engineers to worry about complicating designs.
Created to simplify the design process, the MPS program described in this article is a powerful and easy-to-use graphical user interface (GUI) tool that helps engineers optimize designs. In the example below, the HR121x offers several PFC and LLC control modes, which vary depending on the selected family. These options may seem complicated, but with GUI tools, programming these products is easy. Users only need to simply fill in the corresponding circuit parameters, input the switching frequency according to the design target, and then switch the threshold. Figure 1 shows how to set up the HR1210 using the GUI tool.
Figure 1: HR1210 setup via MPS Adjustable Power GUI
Setting up your device’s basic control mode takes just a few minutes. The HR121x series also supports other advanced features, which we will detail below.
The adjustable 8-level PFC output voltage can be automatically adjusted according to input voltage and load conditions, so that different optimal operating points can be found across the entire operating range (see Figure 2). Engineers do not have to determine the optimal output voltage and do not have to perform additional testing, saving time and cost.
Figure 2: Adjustable PFC output voltage of HR1210
Through the GUI, designers can compensate the reactive current of the input capacitor segment by segment and solve the power factor (PF) problem under light load conditions with the click of a button (see Figure 3).
Figure 3: HR1210 PF compensation function
Designers can also adjust the burst frequency to determine and achieve the best balance between light-load efficiency and audible noise (see Figure 4). This feature greatly reduces test time and provides engineers with greater bandwidth to tune other parameters.
Figure 4: Burst Mode of HR1210
The HR121x family of products with MPS also brings many other benefits. Through the UART port, the physical hardware of the power supply of these products can be connected to the automated test system; and the programmable memory of the HR121x can be used to scan key parameters and measure the efficiency curve of the system. Designers can then analyze and compare data scans to determine optimal parameter settings for the system. Figure 5 shows the efficiency curve plotted for HR1210.
Figure 5: HR1210 Efficiency Curve
With this automated testing method, the user can optimize the design empirically without additional work. In an era where automation continues to replace human labor, choosing the right MPS digital solution can reduce design time, better optimize end-equipment performance, and reduce time-to-market. The HR121x controller family not only meets these needs, but also offers a variety of packages for each product to meet the space requirements of specific applications. This article only covers the HR1210, there are currently four other products in the HR121x series, and more are on the way. To learn more details about the entire HR121x family, check out the video from the MPS APEC 2020 presentation.