System Board 6715

MAXREFDES1105: Miniature, 5V/2A, Synchronous, No-Opto Flyback DC-DC Converter with 90.4% Efficiency Using MAX17690 and MAX17606


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Designed, Built, Tested

The Reference Design Document describes the hardware pictured below. It provides a detailed systematic technical guide to designing a miniature, 5V/2A, synchronous, No-Opto flyback DC-DC converter with 90.4% efficiency using MAX17690 and MAX17606. The hardware was built according to the linked Schematic, Bill of Materials and PCB Artwork. It was tested by Maxim’s expert applications engineering team in a state-of-the-art design lab. Functionality of the design over all electrical operating conditions was verified with the MAXREFDES1105 Simulation Circuit using Maxim’s OASIS Circuit Simulation Tool. Downloadable ECAD/EDA files are available in 7 different formats including OrCAD, Altium, Mentor DX Designer, Eagle and more.

Description

Input Type VIN (MIN)
(V)
VIN (MAX)
(V)
IOUT
(A)
Single/Multiple
Output
VOUT
(V)
POUT
(W)
Isolated/Non-Isolated Topology
DC 18 60 2 Single 5 10 Isolated Flyback

Due to its simplicity and low cost, the flyback converter is the preferred choice for low-to-medium isolated DC-DC power-conversion applications. However, the use of an optocoupler or an auxiliary winding on the flyback transformer for voltage feedback across the isolation barrier increases the number of components and design complexity. The MAX17690 eliminates the need for an optocoupler or auxiliary transformer winding and achieves ±5% output voltage regulation over line, load, and temperature variations.

The MAX17690 implements an innovative algorithm to accurately determine the output voltage by sensing the reflected voltage across the primary winding during the flyback time interval. By sampling and regulating this reflected voltage when the secondary current is close to zero, the effects of secondary-side DC losses in the transformer winding, the PCB tracks, and the rectifying diode on output voltage regulation can be minimized.

The MAX17690 also compensates for the negative temperature coefficient of the rectifying diode.

MAXREFDES1105 Board Enlarge+


This board is not available for purchase.

Key Features

  • 4.5V to 60V Input Voltage Range
  • Programmable Switching Frequency from 50kHz to 250kHz
  • Programmable Input Enable/UVLO Feature
  • Programmable Input Overvoltage Protection
  • Adjustable Soft-Start
  • 2A/4A Peak Source/Sink Gate Drive Capability
  • Hiccup Mode Short-Circuit Protection
  • Fast Cycle-by-Cycle Peak Current Limit
  • Thermal Shutdown Protection
  • Space-Saving, 16-Pin, 3mm x 3mm TQFN Package
  • -40°C to +125°C Operating Temperature Range
 

Reference Design Document

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Bill of Material

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Status:
Package:
Temperature:

MAX17690
60V, No-Opto Isolated Flyback Controller

  • 4.5V to 60V Input Voltage Range
  • No Optocoupler or Third Winding Required to Derive Feedback Signal Across Isolation Boundary
  • 2A/4A Peak Source/Sink Gate Drive Currents

MAX17606
Secondary-Side Synchronous MOSFET Driver for Flyback Converters

  • Wide 4.5V to 36V Input
  • 2A/4A Peak Source/Sink Gate Drive Currents
  • Suitable for Discontinuous Conduction Mode (DCM), Border Conduction Mode (BCM)