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Microchip has launched a new power control reference design to realize the secondary side microcontroller to control the main power supply.

January 08, 2021


The new AC-DC controller uses the Inde-Flux™ transformer technology authorized by Würth ElektronikeiSos to simplify design, reduce size and reduce costs.

In modern offline AC-DC power solutions, programmability and adaptive control provide the flexibility and intelligence required by smart home devices to better connect with the power system. In these systems, the secondary side microcontroller (MCU) usually cannot start the system without using an independent bias power supply. MicrochipTechnologyInc. (American microchip science and technology company) introduced a new reference design, using MCP1012 high-voltage auxiliary AC-DC controller to solve this problem, can cancel the independent bias power supply in many applications. The MCP1012 offline auxiliary device enables the system to transfer power and duty cycle control to the secondary side microcontroller. By simplifying the design, reducing the size and cost, the control between the system and the load can achieve more precise and purposeful coupling.


The reference design uses patented isolation technology to isolate feedback. This patented isolation technology is called Inde-Flux transformer technology and has been licensed to Würth ElektronikeiSos. The Inde-Flux transformer (part number 750318659) is the first transformer manufactured by Würth ElektronikeiSos using this patent, and will be sold as a component of the Microchip 15WMCP1012 offline reference design. This transformer combines signal power and signal communication into one device without the need for optical feedback or a separate signal transformer. The new reference design can also choose to adopt a more traditional approach, using a planar pulse transformer to work with more traditional optocouplers and signal transformers. By using this transformer and Microchip's new MCP1012AC-DC controller and SAMD20 series of 32-bit microcontrollers, secondary side control can be achieved.

The MPC1012 primary side auxiliary controller provides the functions of system startup, gating and protection of the offline flyback converter for the secondary side microcontroller. The device has a series of functions, such as direct measurement and active voltage regulation or current stabilization, high loop bandwidth through direct closed loop, and simplified communication of load reference system.

The 15WMCP102 offline reference design provides the main working elements for the 15W offline power supply design and is equipped with necessary firmware to eliminate the primary side auxiliary power supply. This can reduce the complexity of the system, including eliminating the need for optocouplers in many applications, such as home appliances and smart speakers. With the support of Würth ElektronikeiSos, Inde-Flux transformer technology can be expanded to standard and custom transformer designs for different voltages and power levels as needed.

Rich Simoncic, Senior Vice President of Microchip's Analog, Power and Interface Business Unit, said: "Combining the Würth ElektronikeiSos transformer with Inde-Flux technology with our MCP1012AC-DC controller and SAMD20 series of 32-bit microcontrollers creates a unique feature for offline power management. Solution. These devices can realize complex two-way communication between main components and auxiliary components more simply and more reliably. These components are used in many isolation applications that use offline power supplies. When the solution is used in systems with secondary side microcontrollers At this time, customers can save up to 60% of the area of the bias power supply and reduce the cost of the bias power supply bill of materials by more than $3."