DC/DC LLC Resonant Converter Reference Design

The 200W DC/DC LLC resonant converter reference design simplifies the design course of. It operates over a large enter voltage vary and delivers excessive effectivity.

Among the many varied DC/DC converter topologies accessible in the present day, designers sometimes select one based mostly on a stability of conflicting necessities. Effectivity, energy density (i.e., the converter’s measurement), and value are the first concerns within the design course of. The resonant converters, particularly LLC resonant converters, provide all the specified options. They supply a compact and extremely environment friendly design. Moreover, their functionality to keep up a regulated output voltage over a large enter voltage vary helps decrease the general system price. 200W DC/DC LLC resonant converter reference design by Microchip simplifies the design course of.

The reference design operates over a large enter voltage vary of 350-420 Vdc, with a nominal enter of 400V, delivering a 12V DC output whereas sustaining high-voltage isolation between the first and secondary sides. Excessive effectivity is achieved via Zero Voltage Switching (ZVS) on the half-bridge converter and Zero Present Switching (ZCS) on the synchronous rectifier. Utilizing a synchronous rectifier as an alternative of the normal full-wave rectifier additional enhances effectivity. The reference design makes use of Microchip’s digital energy conversion dsPIC for adaptive management of the half-bridge converter and synchronous rectifier.

This design makes use of a single dsPIC33EP / dsPIC33FJ “GS” digital-power DSC from Microchip, offering full digital management of energy conversion and system administration capabilities. Utilizing dsPIC33EP / dsPIC33FJ ‘GS’ gadgets effectively permits designers to simply and cost-effectively create merchandise utilizing superior switching strategies, resembling LLC, that cut back switching losses and obtain efficiencies as excessive as 95%. 

Functions using the LLC converter can profit from two essential options: very low switching losses leading to excessive effectivity and the flexibility to regulate the output voltage underneath all load and line situations. The system options low energy consumption at no load, programmable soft-start performance, and complete monitoring and safety for voltage, present, and temperature. It additionally contains full digital management and management of each major and secondary MOSFETs.

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The switching circuit makes use of a half-bridge topology, permitting the output voltage to oscillate between 0V and a nominal 400V dc. Whereas a full-bridge circuit might even have been used, the half-bridge was chosen for its simplicity and fewer parts. The resonant tank circuit consists of a capacitor, an inductor, and an isolating transformer. The transformer’s magnetizing inductance successfully replaces the required second inductor; generally, even the first inductor could also be built-in into the transformer. Such a configuration minimizes the converter’s measurement, price, and complexity. On the secondary facet, a synchronous rectifier enhances the system’s general effectivity.

Microchip has examined this reference design. It comes with a invoice of supplies (BOM), schematics, meeting drawing, printed circuit board (PCB) format, and extra. The corporate’s web site has extra knowledge in regards to the reference design. To learn extra about this reference design, click on right here.