MAX5974B
Description
The MAX5974_ provide control for wide-input-voltage, active-clamped, current-mode PWM, forward converters in Power-over-Ethernet (Po E) powered device (PD) applications. The MAX5974A/MAX5974C are well-suited for universal or tele input range, while the MAX5974B/ MAX5974D also acmodate low input voltage down to 10.5V. The devices include several features to enhance supply efficiency. The AUX driver recycles magnetizing current instead of wasting it in a dissipative clamp circuit. Programmable dead time between the AUX and main driver allows for zero-voltage switching (ZVS). Under lightload conditions, the devices reduce the switching frequency (frequency foldback) to reduce switching losses. The MAX5974A/MAX5974B feature unique circuitry to achieve output regulation without using an optocoupler, while the MAX5974C/MAX5974D utilize the traditional optocoupler feedback method. An internal error amplifier with a 1% reference is very useful in nonisolated design, eliminating the...
