Introduction

Traditional flyback architectures can no longer meet the requirements of high switching frequency, high power density, and high efficiency for high-power adapters. As a result, the LLC architecture, better suited for higher power outputs, has been introduced into 100W+ high-power adapters. This effectively improves conversion efficiency, reduces size, enhances portability, and increases product competitiveness.

Additionally, due to the use of large-capacity filter capacitors in rectified switching power supplies, which exhibit capacitive loads, significant high-order harmonics are generated during the charging and discharging processes, causing pollution and interference in the power grid. To address this, engineers have begun incorporating PFC (Power Factor Correction) circuits into switching power supplies. For power supplies exceeding 75-85W, PFC circuits are mandatory to improve the power factor and correct load characteristics.

In response to the current trends of high efficiency and miniaturization in adapters, MPS has introduced a range of PFC+LLC combo controllers to help manufacturers significantly enhance product integration. Recently, ChargerLab identified multiple devices equipped with MPS PFC+LLC controllers. The following article will provide a detailed introduction.

MPS HR1275

HR1275 is a multi-mode PFC+LLC two-in-one controller with integrated CrM/DCM. The chip can be configured through the UART interface, and the parameters can be adjusted according to the needs to optimize the power supply design. The chip has a no-load power consumption of less than 85mW, uses a high-voltage current source at startup, and can be discharged during AC power failure through smart X capacitors.

Regarding PFC control, HR1275 can maintain high efficiency from light load to full load and has intelligent valley switching technology and input capacitor current compensation function to reduce noise and improve system efficiency. The LLC control part adopts current mode control, supports precise burst mode entry and exit control, has 600V high-side gate drive capability, and has adaptive dead time adjustment and capacitor mode protection. The chip also has over-temperature, over-current, and over-power protection, supports a maximum operating frequency of 500kHz, and is suitable for high-efficiency power supply design.

Application Cases

DAO 150W GaN Charger

The DAO 150W GaN Charger adopts a transparent shell design, which allows you to observe the internal components of the charger. It is also equipped with RGB LED lights and a color LCD screen. Overall, it is very cool and can also provide real-time information on the power supply status of the charger. This charger has two USB-C, one USB-A, and one DC port. The USB-C interface supports PD3.1 140W fast charging, and the DC interface has an output power of 150W, which can meet the power supply needs of laptops and mobile phones.

Teardown of DAO 150W GaN Charger PA0228

PANDAER 120W Three USB-C GaN Desktop Charging Socket

This GaN desktop charging socket adopts a square brick design, with an AC jack on the top and three USB-C ports on the front. The socket has an independent touch power switch for AC power control and built-in surge protection devices for lightning protection. The USB-C ports all support 100W fast charging output, support multiple power output combinations such as 100+20W and 60+60W, and will not be disconnected when a new device is connected, allowing three devices to be fast charged at the same time.

Teardown of PANDAER 120W Three USB-C GaN Desktop Charging Socket

Summary of ChargerLAB

ChargerLAB learned that the three chips launched by MPS, HR1211, HR1270, and HR1275, integrate LLC and PFC technologies, bringing new digital solutions for high-power power adapters and industrial power applications. The built-in digital cores of these three chips support UART interfaces, allowing engineers to program through an intuitive graphical interface, greatly simplifying the design process and improving product efficiency and reliability.

The chip mentioned in the article innovatively combines the PFC+LLC two-in-one design, which not only simplifies the primary circuit but also reduces the number of peripheral components used, making it a highly competitive power chip. At present, MPS's LLC+PFC chip has been adopted by high-power adapters of many manufacturers such as Microsoft, Momax, lifeme, and L Lab. It is believed that in the future, more high-power power supplies will choose to be equipped with MPS's LLC+PFC chip to achieve more efficient and stable DC output.