Using a single MCU, ROHM’s new reference design (REF67004) can handle two commonly power converter types in consumer and industrial power supply applications: quasi-resonant flyback and critical conduction mode PFC (Power Factor Correction). This is a component of the analog-digital hybrid control technology used in ROHM’s LogiCoA Power Supply Solution.
It blends a digitally managed power supply circuit based on the low-power LogiCoA MCU with an analog-controlled power stage circuit that uses ROHM’s excellent silicon MOSFETs and gate driver ICs.
Industrial robots and semiconductor production equipment are two examples of small- to medium-power industrial applications that frequently use analog-controlled power sources. However, it is becoming more and more difficult for analog-only designs to match market expectations because to the increased need for more precise control and improved reliability.
However, because digital controllers are expensive and use a lot of power, their use in the small to medium power range has been restricted, even though fully digital power supplies provide more flexibility and fine control.
In order to address these issues, ROHM created the LogiCoA Power Supply Solution, a hybrid strategy that combines the benefits of digital and analog control. The low power LogiCoA MCUs make it simple to control different power topologies when combined with ROHM’s strong performance.
Using a non-isolated buck converter circuit, users can investigate the LogiCoA Power Supply Solution as the initial step thanks to ROHM’s provision of the REF66009 evaluation reference design. The introduction of the reference design, REF67004, which incorporates both PFC and flyback converters—topologies frequently seen in consumer and industrial equipment—came next.
The newly introduced REF67004 is a reference design that boosts AC input using a Critical Conduction Mode PFC converter, followed by a Quasi-Resonant Flyback converter to deliver a regulated DC 24V output.
Features include a calibration function that compensates for variations in the external component characteristics, enabling the LogiCoA MCU to perform high-precision voltage configuration and overcurrent protection.
This allows for reduced design margins, making it possible to select more compact (low power) power devices and inductors, ultimately helping to minimize PCB area and lower overall system costs.
The REF67004 also includes a logging function that allows the LogiCoA MCU to store operational data, such as input/output voltage, current, temperature, pre-shutdown system status, and cumulative operating time, in its built-in non-volatile memory.
This data can be analyzed to easily identify the root cause of power supply failures. On top, various power control parameters and operational history can be easily configured and retrieved from a PC via UART (with a signal conversion device) using sample programs, including the RMOS (Real-time Micro Operating System) power control OS, available on ROHM’s website.
Practical evaluation is possible through the use of the reference design board LogiCoA003-EVK-001. Going forward, ROHM will continue to provide a variety of power supply reference designs to support and accelerate customer power supply development.
LogiCoA™ Power Supply Solution Page
The basic architecture and key features of the LogiCoA Power Supply Solution are available on ROHM’s website.
LogiCoA™ Power Supply Solution Reference Design Lineup
In addition to sample software, a variety of tools necessary for evaluation, such as circuit diagrams, PCB layouts, parts lists, and support documents are available on ROHM’s website, while actual device evaluation is also possible using the reference design board.
Going forward, ROHM will continue to expand its lineup of reference designs to support a wide range of power topologies.
LogiCoA™ MCU Lineup
Key features include a built-in 3ch analog comparator that can be synchronized with timers, along with a D/A converter that enables digital control of various parameters to support different power supply topologies.
LogiCoA MCU Development Support System
Built on a ROHM’s proprietary 16bit RISC CPU core, LogiCoA MCUs are fully supported by a dedicated integrated development environment and emulator tools.
For more information on the LogiCoA development support system and a product overviews, please visit ROHM’s LogiCoA MCU development system support page (link below).
https://www.rohm.com/lapis-tech/product/micon/logicoa-software
