With the advantage of high efficiency, the LLC topology replaces the traditional flyback circuit in many occasions, and obtains higher efficiency in household appliances, thereby meeting the energy consumption requirements. The LLC topology is suitable for home appliances with fixed voltage applications, and in recent years it has also been gradually used in high-performance small-footprint chargers such as notebook adapters and PD fast chargers.
Since the LLC topology requires a fixed input and output voltage, and the LLC topology can also be used with high-power power supplies, the LLC needs to add a first-level PFC power factor correction circuit. The PFC stage is not only used to correct the power factor, but also to output a stable DC voltage to power the LLC stage. In the early days, it was implemented in the form of independent PFC controller + independent LLC controller, and the number of components was large.
With the improvement of power integration in recent years, many original manufacturers have launched PFC and LLC two-in-one Combo controllers, which integrate the functions independently implemented by two chips into one chip to simplify power supply design. Not only does it reduce the number of components, but the PFC stage can also dynamically adjust the operating state with the LLC stage load, which can meet higher energy efficiency requirements and become the mainstream high-performance power supply solution in recent years.
STmicroelectronics introduces the STNRG011, a digitally controlled PFC+LLC 2-in-1 controller in soo20 packages that feature fewer external components, lower no-load power consumption, higher light-load efficiency, and improved dynamic response than traditional two-chip power solutions.
ST's STNRG011 is a digital multi-mode PFC+ST patented time shift control mode LLC controller with 800V high-voltage start-up circuit, input voltage detection and X-capacitor discharge to reduce standby power consumption. The built-in PFC controller supports input voltage feed-forward, THD optimization, and frequency limiting, operating in critical mode in enhanced fixed on-time mode.
STNRG011 has a complete set of built-in PFC protection, easy time control of the resonant half-bridge, enhanced light-load Burst Mode support for fast Burst Mode, and built-in complete half-bridge protection function. Can be used in open power supplies, flat panel TV power supplies, PC power supplies and adapter applications.
The STNRG011 is available in a SO20 package with blocks of pins that separate the high voltage and drive pins from the sampling pins for easy circuit optimization. Built-in 8-bit digital core control, built-in digital algorithms and hardware analog circuits, to achieve high performance and high reliability of power supply design. The chip's built-in ROM memory stores the algorithm, and parameters can be stored in the device memory during the production phase for flexible functional configuration. It also supports UART pin communication, implements monitoring functions, connects external memory, or updates internal storage information from external memory.
In the application circuit diagram of STNRG011, a single chip achieves complete PFC+LLC control. The chip is controlled by a digital core, and a number of key parameters support programming configuration, built-in comprehensive protection functions, and support the protection function configured by the chip's built-in memory. The addition of digital cores greatly reduces the difficulty of power supply development and debugging.
In addition to controllers with built-in digital cores, ST also has microcontroller solutions dedicated to power control, enabling flexible high-power power supply designs by driving switch tubes with external drivers.