A switching converter based electronic load

Electronic loads (E-Load) are commonly used to test power supplies. In order to test computer power supplies, the E-Load must possess an ideal controlled current source property which draws a desired load current even in the case of a very low terminal voltage of the Source-under-test (SUT). It also needs to have superior dynamic performance to simulate high slew rate load transients. This paper proposes the design of a switching converter based E-Load architecture with very large operational bandwidth. The overall architecture of the E-Load consists of a low-bandwidth converter, which functions under steady-state, and a high-bandwidth auxiliary circuit that is only active during transient load scenario. The converter circuit is realized using a novel switched-boost topology and the auxiliary circuit is realized using a MOSFET operating at the edge of saturation and linear region. A prototype is built to test the proposed architecture. The operational input voltage (SUT voltage) ranges of the prototype are between 0.5 V to 6 V. The load current range is between 0.75 A to 7 A. The results also validate the excellent dynamic characteristics of the proposed architecture.