The regulator, examples of which are shown in FIGS. 2 and 3, may alternatively include a boost, e.g. voltage-increasing, or buck-boost configuration instead of or addition to the shown buck configuration as drawn, depending on the power source voltage and load voltage. A buck-boost regulator configuration connects the input voltage source directly to the inductor while in an “on” state. This results in the accumulation of energy in the inductor. In this state, the capacitor supplies energy to the output load. While in the “off” state, the inductor is connected to the output load and capacitor, so that energy is transferred from the inductor to capacitor and the resistor. A mixed-signal implementation of an integrator/current control may also be realized by using a sigma-delta modulator (a switched-capacitor filtering circuit) to act as an integrator, and converting the analog into the digital domain. Then, a simple digital comparison may be done to arrive at the proper current limit value. Implementation of digital comparisons may also be used, such as for example a simple up-down counter, or a digital signal processor (DSP), general purpose microprocessor, field programmable gate array (FPGA), or application-specific integrated circuit (ASIC). An alternative configuration of the current limit adjustment circuit may be implemented by performing a true power calculation for either the power source or load. This requires the measurement of both voltage and current for either the power source or load. The load current adjustments may be made in response to the calculations such that the power source voltage corresponding to true maximum power transfer can be achieved. This alternative implementation may utilize analog, digital, or mixed-signal circuitry.