RD-183 - Quarter-Brick High Voltage, 3.3V, 30A Reference Design
Design Specifications
  Input Range Output
  LM5035C    VinMin = 36V     Vout1 = 3.3V  
  VinMax = 75V     Iout1 = up to 30A  

Design Description

The LM5035C evaluation board is designed to provide the design engineer with a fully functional power converter based on the Half Bridge topology to evaluate the LM5035C controller.

The LM5035C is a functional variant of the LM5035B Half-Bridge PWM Controller. The amplitude of the SR control signals are 5V instead of the VCC level. The evaluation board is provided in an industry standard quarter-brick footprint.

This reference design features the LM5035C pulse-width modulation (PWM) controller and Silicon Labs' Si8420 ISOpro™ digital isolator. It demonstrates a viable 36V to 75V input half-bridge converter for power module or embedded power applications. The design survives input transients up to 100V as commonly required in communications equipment and protects the power distribution system with hiccup-mode fault protection.

Silicon Labs' ISOpro family of digital isolators employs digital RF technology to communicate data across an isolation barrier. Using the Silicon Labs Si8420 digital isolator in place of pulse transformers eliminates numerous design issues such as duty cycle limitations and non-monotonic decay of output during shutdown. In addition, use of digital isolators improves efficiency and saves board space by eliminating the need for pulse transformers.

  Design Resources
• RD-183 Reference Design
•  CAD Design Files (source schematic, board layout and gerber files)
• Application Note 2043 LM5035CEVAL Evaluation Board Documentation
 
Video:
"LM5035C & LM5039 Controllers Enable Smarter, Higher Density Isolated Power Supplies"
Date: 3/10/2010
Length: 0:06:11
  Article: How2Power "Digital Isolators: A Space-Saving Alternative to Gate-Drive Transformers in DC-DC Converters"
by Bob Bell and Don Swanson March 2010

Additional Product Resources

LM5035C - PWM Controller with Integrated Half-Bridge and SyncFET Drivers
 
  • datasheet
  • application notes
  • samples
Si8420 - ISOpro Digital Isolator
   link is to Silicon Labs website
 
  • datasheet
  • application notes
  • samples
   Features
The performance of the evaluation board is as follows:
  • Input operating range: 36V to 75V
  • Output voltage: 3.3V
  • Output current: 0 to 30A
  • Measured efficiency: 89% at 30A, 92% at 15A
  • Frequency of operation: 400 kHz
  • Board size: 2.28 x 1.45 x 0.5 inches
  • Load Regulation: 0.2%
  • Line Regulation: 0.1%
  • Line UVLO (33.9V/31.9V on/off)
  • Line OVP (79.4V/78.3V off/on)
  • Hiccup current limit

LM5035CEVAL Quarter-Brick Evaluation Board

LM5035CEVAL Quarter-Brick Evaluation Board