MAX5929BEEG+

The MAX5929BEEG+ is a high-voltage, high-power hot-swap controller specifically designed to protect upstream power supplies and downstream loads during system power-up, power-down, or unexpected transients on the system bus. The MAX5929BEEG+ features a high-side MOSFET with an adjustable current limit for optimal sequencing of the load. The device also integrates a 12.5-V tolerant supervisor, an adjustable voltage monitor, and logic I/O that can be used to monitor power supply current, system temperature, input power fault, or control various alarm and shutdown functions.

The MAX5929BEEG+ application field includes applications like board-level hot-swap (BLHS), system-level hot-swap (SLHS), power distribution boards and power entry systems. The MAX5929BEEG+ ensures a safe insertion of downstream USB, Ethernet, other communication and power supplies into a live +48V system. It limits inrush currents, aiding the insertion of boards, the removal of boards, and other fault conditions safely.

The working principle of the MAX5929BEEG+ involves two stages of operation. During the board insertion stage, a voltage-sense circuit continuously monitors the supply voltage. When the +48V bus voltage rises above an internally programmed voltage level (e.g., 20V), the MOSFET gate is pulled low and the MOSFET turns on to allow external current to pass, limiting it based on the VIN sense resistor value.

In the second stage, once the +48V bus voltage has reached its steady-state, the voltage-sense circuit switches off the MOSFET. At this point, the MAX5929BEEG+ monitors the voltage between the VOUT and VIN pins to ensure that the board remains properly connected to the +48V bus. If the sensed voltage between the VOUT and VIN pins drops below a predetermined voltage level (e.g., 16V), it indicates that the board has been disconnected or other fault condition has occurred. The MAX5929BEEG+ then pulls the MOSFET gate low to turn off the MOSFET, thus disconnecting the board from the +48V bus.

Additionally, the MAX5929BEEG+ includes an adjustable voltage monitor that allows the designer to set a predetermined level, at which the MAX5929BEEG+ turns off the MOSFET. The adjustable voltage monitor feature allows the designer to ensure that a board remains connected only when it is above a certain input voltage. If the input voltage drops below the predetermined level, the MOSFET will be turned off to disconnect the board from the +48V bus.

The MAX5929BEEG+ also features various digital input and output signals for additional control and monitoring of the board, such as allowing the system to detect when the board is removed from the +48V bus and providing status information to other systems in the system.

In summary, the MAX5929BEEG+ is a high-voltage, high-power hot-swap controller that provides board-level hot-swap (BLHS), system-level hot-swap (SLHS), power distribution boards and power entry systems with two stages of operation to ensure system safety during system power-up, power-down, or unexpected transients on the system bus. The device also offers an adjustable voltage monitor, logic I/O to monitor power supply current, system temperature, input power fault, or control various alarm and shutdown functions.