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No-Opto Isolated DC-DC Flybacks for Smart Factories and Building Automation

May 6, 2021

Raghu Nathadi  By: Raghu Nathadi
 Senior Business Manager, Industrial Power, Maxim Integrated 


Factories are getting smarter with the adoption of Industry 4.0 and with the advancement in robotics. Modern factories have multitude of sensors deployed throughout the factory for monitoring and collecting data. This data gets processed through Programmable Logic Controllers which are used for automation, asset management, maintenance, and repairs. Similarly, buildings are also getting smarter, not only to save energy, but also to increase the life of the facilities and to improve the comfort of the occupants. Modern buildings have several electronics deployed to manage assets such as elevators, water pumps, air conditioners and IT infrastructure.

Factory AutomationBuilding Automation, PLCs, Programmable controllers, Motor Drives, Isolated DC-DC, No-Opto, Flyback Converter, Primary side Control

It is obvious that all the systems mentioned until now need state of the art electronic circuits and those electronic circuits need to be powered. Some circuits need an isolated power supply to provide safety isolation, or to break ground loops, or to provide power to the high side circuitry that is not referenced to ground.

Theses modern systems need high performance, high power conversion efficiency and at the same time they need the smallest solution size possible. This is a difficult balancing act for design engineers.

Isolated DC-DCs are traditionally implemented using an opto-coupler based secondary side feedback or by using a complex third winding transformer to implement primary side control. The opto-coupler based implementation requires more components, higher cost, and less reliability over the life of the equipment. The third winding transformer-based implementation suffers from poor regulation and the need for a complex transformer design.

But there is no need to panic, Maxim has developed No-Opto Flyback technology to overcome these challenges. Fortunately, these new No-Opto Flyback solutions eliminate the opto-couplers, associated feedback circuitry and the need for third transformer winding. The new solutions also provide new benchmark for its output voltage accuracy at +/-5%, over line, load, and temperature. Maxim offers two versions of the No-opto Flyback Converter. The MAX17690 is a No-Opto Flyback with the switching MOSFET external to offer the flexibility for the designer to choose the right MOSFET based upon the power and voltage needs. The MAX17691/2/3 No-Opto Flybacks integrate the switching MOSFET into the controller which keeps the solution size and external component count to the lowest.