New Industry Products

250W Digital LLC DC-DC Converter with GaN Power FETs – Reference Design

April 23, 2020 by Paul Shepard

The fully digital design of the KV46 digital LLC dc-dc converter reference design is based on NXP's HVP-LLC development board. The HVP-LLC dev board is an integral part of NXP high-voltage platform. In combination with the HVP-KV46F150 controller card, it provides a ready-made software development platform for 250W LLC dc-dc converter with an input voltage of 390Vdc and a 12V / 21A output.

This dc-dc converter design includes GaN power FETs and synchronous rectification, plus analog sensing (resonant tank current, output voltage, output current). It has a PMBus communications interface and over current protection on both the input and output.


Digital LLC converter - block diagram (click on image to enlarge)

Kinetis KV4x-168MHz Overview

The Kinetis® KV4x family of MCUs is a high-performance solution offering exceptional precision, sensing, and control for some of the most demanding applications in motor and power control. Built upon the Arm® Cortex®-M4 core running at 168MHz with DSP and floating point unit, it features advanced high-speed and high-accuracy peripherals such as high-resolution pulse-width modulation (PWM) with 312 picosecond resolution, dual 12-bit analog-to-digital converters (ADCs) sampling at 4.1 mega samples per second (MSPS), a total of 30 pwm channels for support of multi-motor systems and dual FlexCAN modules. To maximize execution performance a 128-bit wide flash interface is utilized.

Kinetis KV4x-168MHz Features

  • 168MHz Cortex-M4 core with DSP, floating point unit - improves performance in math-intensive applications (e.g., processing of sensorless FOC (field oriented control) algorithms)
  • 128-bit wide flash interface with a cache to minimize the number of wait states while executing fast control loops
  • 2x 12-bit, 16-channel ADCs with PGAs - 4.1 MSPS ideal for digital power conversion or for motor control applications
  • Up to 12 channel eFlexPWM - up to 312ps resolution for demanding digital power conversion applications
  • Up to 2 x 8-channel and 1 x 2-channel programmable FlexTimers - high-accuracy PWM generation with integrated power factor correction or speed sensor decoder (incremental decoder/hall sensor)
  • Quadrature encoder/decoder
  • Up to 2 FlexCAN modules - high-speed, high-reliability industrial communication
  • Broad family scalability with hardware and software compatibility - easy migration to more performance, memory and feature integration within the Kinetis® V series