MAXREFDES1122: 24W DC-DC flyback converter using MAX17596

The MAX17596 is a peak-current-mode controller for designing wide input-voltage flyback regulators. The device offers input thresholds suitable for low-voltage DC-DC applications (4.5V to 36V) and contains a built-in gate driver for an external n-channel MOSFET. The MAX17596 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 MAX17596 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
• 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

This board is not available for purchase.

Designed, Built, Tested

This document describes the hardware shown in Figure 1. It provides a detailed systematic technical guide to designing a DC-DC discontinuous conduction mode (DCM) flyback using Maxim’s MAX17596 current-mode controller. The power supply is designed, built and tested.

Design Resources