DC2046A-D Analog Devices

DEMO MANUAL DC2046A-D LT4276, LT4321 PoE PD with Synchronous Flyback and Ideal Diode Bridge DESCRIPTION Demonstration circuit 2046A-D is a PoE Powered Device topology with synchronous rectification. The LT4321 (PD) with an isolated power supply using synchronous provides further efficiency improvement by minimizing flyback topology, featuring the LT 4276 and ideal diode the bridge losses. bridge controller (LT4321). The DC2046A-D supplies a 24V output at up to 0.95A. It The LT4276 provides IEEE802.3af (PoE, Type 1), also demonstrates the use of an optional auxiliary power + ++ IEEE802.3at (PoE , Type 2), and LTPoE PD interfacing supply input of 48V. When present, the auxiliary supply and power supply control. When the PD is fully powered, becomes the dominant supply over PoE to provide power. the PD interface switches power over from the Power Design files for this circuit board are available at Sourcing Equipment (PSE) to the switcher through an DEMO MANUAL DC2046A-D TYPICAL PERFORMANCE CHARACTERISTICS Top Side Bottom Side Figure 1. Thermal Pictures V = 57V, 24V/0.95A PORT 94 25.0 92 24.8 90 24.6 24.4 88 24.2 86 84 24.0 82 23.8 80 23.6 78 23.4 V = 42.5V V = 42.5V PORT PORT V = 50V V = 50V PORT PORT 76 23.2 V = 57V V = 57V PORT PORT 74 23.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A) LOAD CURRENT (A) DC2046A-D F02 DC2046A-D F03 Figure 2. Efficiency (End to End) Figure 3. Output Voltage Regulation dc2046adf 2 EFFICIENCY (%) V (V) OUT