Circuit and method for generating estimated feedback for the controller of a slave power supply module in a master/slave paralleling scheme

摘要

A feedback circuit (28) is included in paralleled power supply modules (20) using a modified master/slave current sharing scheme. The feedback circuit is activated in the slave modules to force the internal control signal generated by each of the controllers (24) acting as slaves to operate in a predetermined manner. This predetermined manner can be by adjusting the local control signal such that it approximates the master control signal, either by forcing it to follow the master control signal, or by separately regulating the local control signal to approximate the master control signal, or it can be by maintaining the local control signal at a predetermined value. The feedback circuit acts to prevent sudden changes in the output voltage when the master module fails and another module becomes master by placing its control signal on the current-share bus (I share). If the control signal of the new master is too different from the previous control signal, the output voltage of the power supply could move outside the designed tolerances potentially causing the power supply to shut down.