Switching circuits for extracting power from an electric power source and associated methods
A switching circuit for extracting power from an electric power source includes (1) an input port for electrically coupling to the electric power source, (2) an output port for electrically coupling to a load, (3) a first switching device configured to switch between its conductive state and its non-conductive state to transfer power from the input port to the output port, (4) an intermediate switching node that transitions between at least two different voltage levels at least in part due to the first switching device switching between its conductive state and its non-conductive state, and (5) a controller for controlling the first switching device to maximize an average value of a voltage at the intermediate switching node.
1. A method for operating a switching circuit including an input port, an output port, an energy storage device, a first switching device, and a second switching device electrically coupled across the output port, comprising:
in a first operating mode of the switching circuit, controlling switching of the first switching device between its conductive and non-conductive states to transfer power from the input port to the output port; and
in a second operating mode of the switching circuit:
charging the energy storage device with energy extracted from a circuit including the output port, and
using energy stored in the energy storage device to power a controller of the switching circuit and cause the second switching device to operate in its conductive state.
2. The method of claim 1 , further comprising alternating the steps of charging and using, in the second operating mode of the switching circuit.
3. The method of claim 1 , further comprising controlling switching of the first switching device to at least substantially maximize an amount of electric power extracted from an electric power source electrically coupled to the input port, in the first operating mode of the switching circuit.
4. The method of claim 1 , further comprising using the energy stored in the energy storage device to power the controller when an electric power source electrically coupled to the input port provides insufficient power to operate the controller.
5. The method of claim 4 , further comprising powering the controller from an electric power source electrically coupled to the input port, in the first operating mode.
6. The method of claim 1 , further comprising, in the second operating mode, up-converting a voltage across a diode electrically coupled in parallel with the second switching device to a voltage with a sufficiently large magnitude to (a) at least partially power the controller and (b) operate the second switching device.
7. The method of claim 1 , further comprising operating the second switching device in its conductive state in response to a voltage across a diode exceeding a predetermined threshold value for a predetermined amount of time, the diode being electrically coupled in parallel with the second switching device.