Microchip Introduces New Power Control Reference Design for Secondary-Side Microcontroller Control of Main Power

     New AC-DC controller features Inde-Flux™ transformer technology licensed to Würth Elektronik eiSos, simplifying design, reducing size and cost

     In modern offline AC-DC power solutions, programmability and adaptive control provide the flexibility and intelligence required by smart home devices to better interface with the power system. In these systems, the secondary-side microcontroller (MCU) is often unable to start the system without the use of an independent bias supply. Microchip Technology Inc. has introduced a new reference design that solves this problem with the MCP1012 high voltage auxiliary AC-DC controller, which eliminates the independent bias supply in many applications. The MCP1012 off-line auxiliary device enables the system to offload power and duty cycle control to the secondary-side microcontroller. By simplifying the design, reducing size and cost, the control between the system and the load can be more precisely and purposefully coupled.

     The reference design uses a patented isolation technique for isolated feedback. This patented isolation technology, called Inde-Flux Transformer Technology, has been licensed to Würth Elektronik eiSos. The Inde-Flux transformer (part number 750318659) is the first transformer manufactured by Würth Elektronik eiSos using this patent and will be sold as a component of the Microchip 15W MCP1012 offline reference design. This transformer combines signal power and signal communication into one device, eliminating the need for optical feedback or separate signal transformers. The new reference design also has the option of taking a more traditional approach, using planar pulse transformers, working with more traditional optocouplers and signal transformers. Secondary-side control is achieved by using this transformer in combination with Microchip's new MCP1012 AC-DC controller and SAM D20 family of 32-bit microcontrollers.

     The MPC1012 primary-side auxiliary controller provides the secondary-side microcontroller with system startup, gating, and protection of an offline flyback converter. The device has a range of features such as direct measurement and active regulation or current regulation, high loop bandwidth through direct closed loop, and simplified communication to load reference systems.

     The 15W MCP102 offline reference design provides the main operating elements for a 15W offline power supply design with the necessary firmware to eliminate the primary side auxiliary power supply. This can reduce system complexity, including eliminating the need for optocouplers in many applications, such as appliances and smart speakers. With the support of Würth Elektronik eiSos, Inde-Flux transformer technology can be extended to standard and custom transformer designs for different voltage and power levels as required.

     "Combining Würth Elektronik eiSos transformers with Inde-Flux technology with our MCP1012 AC-DC controller and SAM D20 family of 32-bit microcontrollers provides an excellent solution for off-line power management," said Rich Simoncic, senior vice president of Microchip's Analog, Power and Interface business unit. A unique solution has been created. These devices enable simpler and more reliable implementation of complex bi-directional communication between primary and secondary components used in many isolated applications utilizing off-line power. When the solution is used with secondary Customers can save up to 60% in bias power area and reduce bias power bill of materials cost by more than $3 when using a system of stage-side microcontrollers.”