This paper proposes a buck and boost derived converter associated with a full-bridge inverter for livestock/poultry stunning applications. The derived converter is formed by combining buck and boost converters to step up or step down input voltage. Compared with the conventional buck-boost converter, the proposed converter can raise efficiency of 4-6% under full load condition. In the paper, mechanism of livestock/poultry stunning is first reviewed and then, the desired stunning voltage waveforms and parameter auto-tuning algorithm are proposed. The output voltage waveforms generated from the converter and inverter are with frequency varying from 50 Hz to 800 Hz, amplitude varying from zero to its breakdown voltage, as high as 250 V, and duty ratio changing from 0.3 to 0.7. Performance measurements from a prototype have verified the parameter auto-tuning algorithm and feasibility of the overall system design.