Switching converter with open-loop primary side regulation

摘要

The isolated, multiple output, switching converter is created with a number of unique performance characteristics. The converter operates in continuous inductor current mode (CICM) of operation for all load currents from no load to full load on all outputs despite the presence of simple rectifier diodes only on the converter secondary sides. The regulation of output voltages on all outputs against the changes of the input voltage is provided by use of a simple open-loop control circuit connected to the primary side and thus eliminating the need for isolation in the control circuit. The regulation against the load current changes in the single output case is also provided on the primary side by a load current sensing circuit. An additional benefit of the switching converter is in the elimination of the losses and voltage overshoots associated with the leakage inductance of the isolation transformer when operated as pulse width modulated (PWM) converter.