Buck converter based series stacked active power decoupling (SS-APD) circuit is a preferred choice to increase the power density of single-phase converters. Owing to its distinct operating characteristics, the existing design guidelines for SS-APD circuits may not be directly applicable to buck SS-APD circuit. This digest presents a systematic design methodology to minimise the energy stored in the passive components to enable compact design of buck-SSAPD circuit. The design also uses electrolytic capacitors, instead of high voltage ceramic capacitors to limit the cost. The proposed technique is employed to design a buck SS-APD prototype with power density of 404 W/inch3 (by box volume) for a 2 kW, 230 V, 50 Hz single phase inverter with 400 V dc-link.