48V to 12V Regulated / Isolated Quarter Brick with Digital Control – Reference DesignMarch 26, 2020 by Paul Shepard
The REF_600W_FBFB_XDPP1100 reference design from Infineon is a system solution for telecom isolated dc-dc power modules that achieves 96% peak efficiency in a DOSA standard quarter brick form factor. This reference design introduces a secondary side digital control and hard switching full-bridge topology delivering 12V/600W of output power. It operates across a wide range of input voltages (36V to 72V). The achieved power density is 22W/cm³ (360 W/in³), which is enabled by the use of the XDPP1100 digital controller, OptiMOS™ MOSFETs and an EiceDRIVER™ gate driver IC.
Potential applications for this reference design include isolated dc-dc brick modules, telecom infrastructure, server motherboards, 48V computing and datacenter power, and industry 4.0 systems.
The XDPP1100 offers superior levels of integration and performance in a single-chip solution. The XDPP1100 device includes an optimized analog front end, multiple pre-programmed peripherals, a fast state-machine based control loop, and a microcontroller. This unique architecture enhances the performance of isolated dc-dc applications, reduces BOM size, and allows advanced control functions as well as customization, while providing the fastest time to market.
The reference design on top of the XDPP1100 contains the following highlight products: OptiMOS™ 5 100V (BSC050N10NS5), OptiMOS™ 6 40V (BSC010N04LS6), and the EiceDRIVER™ dual-channel, functional isolated gate-driver IC, 2EDF7275K.
Due to the high driving current, excellent common-mode rejection and fast signal propagation, the 2EDF7275K is particularly well suited for driving medium- to high-voltage MOSFETs (CoolMOS™, OptiMOS™) in fast-switching power systems.
The design consists of a primary-side full-bridge converter with synchronous rectification in full-bridge configuration switching at 250kHz, with an Infineon-designed CDL lossless snubber used on the secondary side. The isolated gate driver 2EDF7275K is used on both the primary and secondary side to simplify the Bill of Materials (BOM) and reduce inventory management cost, as shown in the block diagram below.
The loop control is implemented with Infineon XDPP1100-Q040. The XDPP1100 is a digital power supply controller with analog/mixed-signal capabilities, on-chip memories and communication peripherals. The device is specifically optimized to enhance the performance of isolated dc-dc applications and reduce the solution component count in the telecom brick converters. It has a -40°C to 125°C operational temperature range.
The XDPP1100 supports both voltage-mode control and peak-current-mode control. This 600W demo board could be configured to operate in either voltage-mode or peak-current-mode. This document describes voltage-mode control. When configured to voltage-mode, flux balancing is enabled.
Summary of Features
- Digital controlled isolated brick converter
- Voltage mode control with flux balancing
- Fast line and load transient response
- PMBus™ and I2C communication
- Voltage mode control with transformer flux walking protection
- Best in class feed-forward response
- Supports active current sharing between multiple modules
- Smoother pre-bias start-up
- Output voltage accuracy +/-1% over full temperature range -40°C to 125°C
- Configurable with GUI support
- Allows FW based customization
- Configurable output voltage
- Digital control increases overall reliability
- High power density and reduced BOM with component integration
- Pre-programmed control providing the fastest time-to-market
- Provides future proof optimal solution via PMBus™ adjustments