Power converter with modular stages connected by floating terminals
An apparatus for electric power conversion includes a converter having a regulating circuit and switching network. The regulating circuit has magnetic storage elements, and switches connected to the magnetic storage elements and controllable to switch between switching configurations. The regulating circuit maintains an average DC current through a magnetic storage element. The switching network includes charge storage elements connected to switches that are controllable to switch between plural switch configurations. In one configuration, the switches forms an arrangement of charge storage elements in which at least one charge storage element is charged using the magnetic storage element through the network input or output port. In another, the switches form an arrangement of charge storage elements in which an element discharges using the magnetic storage element through one of the input port and output port of the switching network.
1. An apparatus comprising a power converter, said power converter comprising first and second switches, and a set of switching elements for connection to capacitors to form a switched-capacitor network that has first and second terminals, wherein said first and second terminals are at different voltages,
wherein said first switch connects to said first terminal and to an inductor, and
wherein said second switch connects to said inductor and to said first switch,
wherein said first and second switches are configured such that when said first switch is closed and said second switch is open, current through said inductor increases, and when said first switch is open and said second switch is closed, current through said inductor decreases, and
wherein said switched-capacitor network forms first and second paths that extend between said first and second terminals when said set is in corresponding first and second states.
2. The apparatus of claim 1 , wherein said first terminal, to which said first switch connects, is maintained at a lower voltage than said second terminal, and wherein said inductor is disposed to connect to a load.
3. The apparatus of claim 1 , wherein said first terminal, to which said first switch connects, is maintained at a higher voltage than said second terminal, and wherein said inductor is disposed to connect to a voltage source.
4. The apparatus of claim 1 , further comprising a controller for causing said set to assume said first and second states at different times.
5. The apparatus of claim 1 , wherein said first switch comprises a diode having an anode thereof connected to said inductor.
6. The apparatus of claim 1 , wherein said second switch comprises a diode having a cathode thereof connected to said inductor.
7. The apparatus of claim 1 , further comprising a controller, wherein said first switch comprises a synchronous rectifier, said synchronous rectifier having a gate that receives a gate signal that is controlled by said controller.
8. The apparatus of claim 1 , further comprising a controller, wherein said second switch comprises a synchronous rectifier, said synchronous rectifier having a gate that receives a gate signal that is controlled by said controller.
9. The apparatus of claim 1 , further comprising a capacitor connected across an output of said power converter.
10. The apparatus of claim 1 , wherein said set comprises first switching-elements and second switching-elements, wherein said switched-capacitor network comprises a first capacitor and a second capacitor, wherein opening said first switching-elements and closing said second switching-elements charges said first capacitor and discharges said second capacitor, and wherein closing said first switching elements and opening said second switching elements discharges said first capacitor and charges said second capacitor.
11. The apparatus of claim 1 , further comprising a controller configured to cause said first and second switches to switch at a first frequency and to cause said switching elements in said set to switch at a second frequency, said first frequency being different from said second frequency.
12. The apparatus of claim 1 , wherein, when said set is in said first state, only said first path is connected between said first and second terminals, and wherein, when said set is in said second state, only said second path is connected between said first and second terminals.
13. The apparatus of claim 1 , wherein, when an amount of charge stored in a capacitor in said switched-capacitor network changes, an amount of charge passes through said inductor, said amount corresponding to an extent of said change.
14. The apparatus of claim 1 , wherein, when an amount of charge stored in a capacitor in said switched-capacitor network changes, a corresponding amount of charge passes through said inductor, said amount corresponding to only a portion of an extent of said change.
15. The apparatus of claim 1 , wherein said first and second switches are opened and closed at times that limit RMS current through said switched-capacitor network through maintenance of an average DC current through said inductor.
16. The apparatus of claim 1 , further comprising a clock that defines clock cycles, wherein during each clock cycle, charge is pumped from one capacitor to the next along one of said paths.
17. The apparatus of claim 1 , wherein each of said first and second paths comprises at least one capacitor.
18. The apparatus of claim 1 , wherein said wherein said set is further configured to assume a third state in which no current path extends between said first and second terminals.
19. The apparatus of claim 1 , further comprising a controller for controlling said first and second switches such that said first and second switches are not both closed at the same time.
20. The apparatus of claim 1 , further comprising a controller for controlling a duty cycle of said first and second switches, thereby maintaining a voltage difference between said switched-capacitor network and said inductor.