Charge balanced charge pump control

1. A method comprising operating a charge pump in which switches from a first set of switches are configured to couple terminals of capacitors to permit charge transfer between said capacitors and in which switches from a second set of switches are configured to couple terminals of capacitors to a first terminal, wherein said first terminal is selected from the group consisting of a high-voltage terminal and a low-voltage terminal, wherein operating said charge pump comprises cycling said switches through a sequence of states, each state defining a corresponding configuration of said switches, at least three of said states defining different configurations of said switches, wherein, during each of said configurations, charge transfer is permitted between a pair of elements, wherein said pair of elements consists of a first capacitor and an element selected from the group consisting of a second capacitor and said first terminal.

2. The method of claim 1 , further comprising maintaining an average current passing between a regulator and said charge pump.

3. The method of claim 1 , further comprising regulating a current at said first terminal, thereby maintaining an average current passing between a regulator and said charge pump.

4. The method of claim 1 , wherein cycling said switches through a sequence of states includes maintaining each state for a corresponding duration of a fraction of a charge pump cycle time.

5. The method of claim 3 , wherein said durations of said states are selected to maintain balanced charging and discharging of each of said capacitors through said sequence of states of each cycle.

6. The method of claim 1 , further comprising controlling an average current between a regulator and said charge pump.

7. The method of claim 1 , further comprising coupling a regulator to said first terminal.

8. The method of claim 7 , further comprising causing said regulator to provide a current load at said low-voltage terminal of said charge pump.

9. The method of claim 7 , further comprising causing said regulator to operate as a current source at said high-voltage terminal of said charge pump.

10. The method of claim 1 , further comprising coupling said switches from said first and second sets of switches to said terminals of said capacitors.

11. The method of claim 10 , wherein coupling said switches comprises forming a multi-phase charge pump.

12. The method of claim 10 , wherein coupling said switches comprises forming a cascade multiplier.

13. The method of claim 10 , further comprising selecting said regulator to be a buck converter.

14. The method of claim 1 , further comprising receiving sensor signals from at least one of said first and second sets of switches and adaptively adjusting said cycling of said switches through said sequence of states based at least in part on said sensor signals.

15. The method of claim 1 , further comprising coupling a first regulator to said high-voltage terminal and coupling a second regulator to said low-voltage terminal.

16. The method of claim 1 , further comprising controlling least one of said first and second sets of switches and adaptively adjusting said cycling of said switches through said sequence of states based at least in part on sensor signals received from at least one of said first and second sets of switches.

17. An apparatus comprising a controller and a plurality of switches, wherein said plurality of switches, when connected to a plurality of capacitors, forms a cascade multiplier, wherein said controller is configured to cause said switches to execute a plurality of cycles, each of which comprises at least first, second, and third states that last for corresponding first, second, and third state-duration times, each state being associated with a corresponding first, second, and third configuration of said switches, wherein, at the beginning of a cycle, each of said capacitors stores an initial amount of charge, wherein, at the end of said cycle, each of said capacitors stores a final amount of charge, and wherein said first, second, and third state-duration times are selected such that said initial and final amounts are equal.

18. The apparatus of claim 17 , wherein said initial and final amounts are zero.

19. The apparatus of claim 17 , wherein said controller is further configured to cause a transition between states when current through said switches is zero.

20. The apparatus of claim 17 , wherein, among said plurality of capacitors, there exists at least one capacitor that holds a constant amount of charge during at least one of said states.