システムボード 6661

MAXREFDES1186: 7.5W 3.3V Offline Flyback Converter Using the MAX17595


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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
AC 176 284 2.273 Single 3.3 7.5 Isolated Fly Back

The MAX17595 is a peak-current-mode controller for designing wide input-voltage flyback regulators. The MAX17595 offers optimized input thresholds for universal input AC-DC converters and telecom DC-DC (36V to 72V input range) power supplies. It contains a built-in gate driver for an external n-channel MOSFET. The MAX17595 houses an internal error amplifier with 1% accurate reference, eliminating the need for an external reference. The switching frequency is programmable from 100kHz to 1MHz with an accuracy of 8%, allowing optimization of magnetic and filter components, resulting in compact and cost-effective power conversion. For EMI-sensitive applications, the MAX17595 incorporates a programmable frequency dithering scheme, enabling low-EMI spread-spectrum operation. Users can start the power supply precisely at the desired input voltage, implement input overvoltage protection, and program soft-start time. A programmable slope compensation scheme is provided to ensure stability of the peak current-mode control scheme. Hiccup-mode overcurrent protection and thermal shutdown are provided to minimize dissipation in overcurrent and overtemperature fault conditions.

Key Features

  • Programmable Switching Frequency Allows Optimization of the Magnetic and Filter Components, Resulting in Compact, Cost-Effective, Efficient Isolated/Nonisolated Power Supplies
  • 100kHz to 1MHz Programmable Switching Frequency with Optional Synchronization
  • Peak Current Mode Control Provides Excellent Transient Response—Offline (Universal Input AC) and Telecom (36V to 72V) Flyback Controller
  • Programmable Frequency Dithering Enables Low EMI Spread-Spectrum Operation
  • Integrated Protection Features Enhance System Reliability
  • Adjustable Current Limit with External Current Sense Resistor
  • Fast Cycle-By-Cycle Peak Current Limiting Hiccup-Mode Short-Circuit Protection
  • Overtemperature Protection
  • Programmable Soft-Start and Slope Compensation
  • Input Overvoltage Protection
MAXREFDES1186 Hardware 拡大表示+


This board is not available for purchase.

Designed, Built, Tested

This document describes the hardware. It provides a detailed systematic technical guide to designing an offline discontinuous conduction mode (DCM) flyback using Maxim's MAX17595 current-mode controller. The power supply has been built and tested, details of which follow later in this document.

Design Resources

 
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MAX17595
ピーク電流モードコントローラ、フライバックおよびブーストレギュレータ用

  • 設定可能なスイッチング周波数によって磁気およびフィルタ部品の最適化を可能にして、小型で高コスト効率の優れた絶縁/非絶縁型電源を実現
  • 設定可能な周波数ディザリングによって低EMIスペクトラム拡散動作を実現
  • 内蔵保護機能によってシステムの信頼性を向上