Abstract: A power conversion arrangement includes first and an optional second power conversion stages. The first stage has an input configured to receive an input voltage, an output having a first output voltage, a controller, a variable resistance, and a feedback node having a feedback voltage. The feedback node is coupled to the output by a first impedance. The controller receives the feedback voltage, and drives the output such that the feedback voltage is substantially at a predetermined value. The variable resistance is coupled between the feedback node and a reference voltage (e.g., ground). The variable resistance has a resistance value that varies as a function of the input voltage. The second stage has an input operably coupled to receive the first output voltage. The second stage is configured to generate an output voltage having a level that is substantially constant independent of the level of the first output voltage.

Abstract: A biofuel cell device for generating electrical current, comprising a fuel manifold, an anode assembly, a cathode assembly, a housing, and a controller is described. The anode assembly comprises at least one catalyst positioned for contact with fuel fluid in said fuel reservoir. The cathode assembly comprises at least one biocathode positioned for flow of an oxidant to the biocathode enzyme. The housing houses the manifold, anode assembly and cathode assembly. The controller controls the output of electrical current from the biofuel cell device.