Power supplies with foldback protection
MAXIM Integrated Products, represented by Arrow Electronics , has introduced the MAX8545/MAX8546/MAX8548 voltage-mode, pulse-width modulation (PWM), step-down, dc-dc controllers that provide the lowest cost 1A to 15A power supplies.
The MAX8545/MAX8546 operate at 300kHz switching frequency, whereas the MAX8548 operates at 100kHz and is pin replaceable for the MAX1967.
All devices allow low, 0.8V output and feature digital soft-start, current-limit, and foldback short-circuit protection.
These devices provide point-of-load dc-dc conversion in cost-sensitive applications such as set-top boxes, video graphic cards, desktop and motherboard supplies, hard-disk drive supplies, and cable modems.
The MAX8545/MAX8546/MAX8548 integrate powerful gate drivers rated at 2.5 ohms (typ), allowing a wide range of output currents from 1A to 15A.
Current limit (165mV threshold for MAX8545/MAX8548 and 320mV threshold for MAX8546) and short-circuit protection are provided without requiring a current sense resistor, which reduces cost and improves efficiency.
Additionally, foldback current protection reduces current limit by 80%, minimises power dissipation under short-circuit conditions, and latches off the device when an output short is detected.
Thermal-overload protection provides for a rugged power-supply design.
These devices have a 2.7V to 28V input range and do not require additional biasing, making them ideal for 3.3V, 5V, 12V, and 24V bus applications.
The MAX8545EUB/MAX8546EUB/MAX8548EUB are available in 10-pin microMAX packages. Prices start at $0.92 for the MAX8545/MAX8546 and at $0.88 for the MAX8548 (1000-up, FOB USA).
All devices are specified for the extended-industrial temperature range (-40ºC to +85ºC). Evaluation kits and several application circuits are available to speed designs.