Generation of system power-good signal in hot-swap power controllers

Abstract

A power controller system is described herein, which may consist of one or more power controller ICs and other components. Each power controller selectively couples power supply voltages to a plurality of electrical devices, such as cards that have been inserted into expansion slots in a server. To simplify processing by a system processor monitoring the health of the power subsystem, each power controller IC asserts a power-good signal at a power-good terminal only if the operating conditions for all channels are satisfactory. A power good signal is generated even if a channel is not supplying power to a channel due to a card retention switch signal not being asserted or the channel is not enabled. The power-good signals from all power controllers in the system are then ANDed together to determine if any of the power controllers are experiencing unsatisfactory conditions. If the resulting single signal is an asserted power-good signal, then the system knows that all channels in all the power controllers are experiencing satisfactory conditions, even though some channels may not be enabled or there are no modules (e.g., cards) connected to a power controller.