MAX34441,pdf (PMBus 5-Channel Power-Supply Manager)

The MAX34441 is a complex system monitor that can manage up to five power supplies and a fan. The power-supply manager monitors the power-supply output voltage and constantly checks for user-programmable overvoltage and undervoltage thresholds. It can also margin the power-supply output voltage up or down to a user-programmable level. The margining is performed in a closed-loop arrangement whereby the device automatically adjusts a pulse-width-modulated (PWM) output and then measures the resultant output voltage. The power-supply manager can also sequence the supplies in any order at both power-up and power-down. With the addition of an external current-sense amplifier, the device can also monitor currents.

The device also contains closed-loop fan-speed control. Based on user-programmable settings for fan-control PWM duty cycles or RPM speeds at particular temperature breakpoints, the device automatically adjusts the fan speed in a manner to reduce audible noise and power consumption.