系统板 6989

MAXREFDES1194: Five-Output, No-Opto Flyback DC-DC Converter Using the MAX17690


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Input Type VIN (MIN)
(V)
VIN (MAX)
(V)
IOUT
(A)
Single/Multiple
Output
VOUT
(V)
POUT
(W)
Isolated/Non-Isolated Topology
DC 6 60 Io1=50mA
Io2=50mA
Io3=0.3mA
Io4=33mA
Io5=0.3mA
Multiple Output Vo1=3.3V
Vo2=11V
Vo3=10V
Vo4=11V
Vo5=10V
1.084 Isolated No-Opto Flyback

The MAXREFDES1194 is a no-opto flyback DC-DC power supply that delivers five outputs from a 6V to 60V supply voltage. It is designed for equipment that needs multichannel, isolated power supplies with a wide input voltage range.

The MAXREFDES1194 employs the no-opto flyback control technique of the MAX17690. This document explains how the MAX17690 peak current-mode PWM converter can be used to generate five isolated outputs from a 6V to 60V input voltage. An overview of the design specification is shown above.

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.

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
MAXREFDES1194 Board 放大+


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Designed, Built, Tested

This document describes the hardware shown above. It provides a detailed systematic technical guide to designing an isolated no-opto flyback DC-DC converter using the MAX17690 controller. The power supply has been built and tested.

Design Resources

 
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MAX17690
60V、无光耦、隔离反激控制器

  • 4.5V至60V输入电压范围
  • 无需光耦或第三个绕组即可驱动反激信号通过隔离栅。
  • 2A/4A最大源出/吸入栅极驱动电流