Switching converters using double-layer capacitors as power backup

Novel switching power converters using electric double-layer capacitors (EDLCs) as power backup are presented in this paper. The configurations of these circuits are very simple and the number of components in each converter is very small. The unbalance of voltages in EDLCs, that has been one of the main problems of the conventional circuit, does not occur in the new design. A prototype circuit has been built and tested. As a result, good backup performance has been obtained: the backup time when the input voltage source is disconnected is 11.7 sec for an output of 5.0 V and 2.0 A. The efficiency of the new circuit in steady-state operation is 90% for an output voltage of 5.0 V and an output current range of 2.0-4.0 A.