A peak efficiency detection system may include a switched power supply (SPS) module providing an output supply signal. The SPS module may have an internal node, and a plurality of SPS circuits configured to generate the output supply signal on the internal node. A dead type module may generate control signals. A central node external to the SPS module may deliver the output supply signal to a load module. A power stage size control module may generate control signals for controlling the SPS module. A peak-efficiency detection (PED) module may receive the output supply signal from the central node, the control signals from the SPS module, and the control signals from the power stage size control module. The PED module may generate a signal representative of an efficiency of the SPS module.