Fault control for switched capacitor power converter

1. An apparatus comprising a power converter and fault-control circuitry connected to said power converter, said power converter comprising a port for coupling to an external circuit disposed to soft-charge said power converter, and a switched capacitor circuit comprising a set of switches, and a set of capacitors, said set of switches being configured to transition between switch configurations, thereby causing said set of capacitors to transition between plural capacitor networks, and wherein, during operation of said power converter, said fault-control circuitry is configured to carry out an action selected from the group consisting of detecting a fault in said operation and responding to said fault, wherein said fault-control circuitry comprises a disconnect switch having a maximum voltage rating greater than a voltage rating of at least one switch element in said set of switches, said disconnect switch being configured to electrically disconnect or limit current flow through a switch element in said set of switches.

2. The apparatus of claim 1 , wherein said external circuit is configured to soft-charge at least one capacitor from said set of capacitors.

3. The apparatus of claim 1 , wherein said external circuit is configured to soft-charge all capacitors from said set of capacitors.

4. The apparatus of claim 1 , wherein said external circuit is configured to cause a rate of charge transfer between capacitors in said set of capacitors to be proportional to a current through an external port of said power converter.

5. An apparatus comprising fault-control circuitry and a switched capacitor circuit connected to said fault-control circuitry, said switched capacitor circuit comprising a set of switches, a set of capacitors, and a port, said set of switches being configured to transition between first and second switch configurations, thereby causing said set of capacitors to transition between forming a first capacitor network and forming a second capacitor network, said port having an average dc current therethrough, said switched capacitor circuit being configured for connection to an external circuit, wherein said fault-control circuitry is configured to detect a fault in operation of said switched capacitor circuit and to respond to said fault, wherein said fault-control circuitry comprises a disconnect switch having a maximum voltage rating greater than a voltage rating of at least one switch in said set of switches, said disconnect switch being configured to electrically disconnect or limit current flow through a switch in said set of switches.

6. The apparatus of claim 5 , wherein-said set of switches comprises high-side and low-side phase switches that open and close together and wherein during normal operation of said power converter, currents through said high-side and low-side phase switches are equal.

7. The apparatus of claim 1 , wherein said action is selected to be detecting said fault.

8. The apparatus of claim 5 , wherein said fault-control circuitry is configured to measure a current characteristic of at least one switch element in said set of switches.

9. The apparatus of claim 1 , wherein said fault-control circuitry is configured to measure at least one electrical characteristic from within said switched-capacitor circuit, wherein said electrical characteristic is selected from the group consisting of a voltage characteristic and a current characteristic, wherein said current characteristic comprises a current through a component in said switched-capacitor circuit, wherein said voltage characteristic is a voltage across a component in said switched-capacitor circuit.

10. The apparatus of claim 5 , wherein said first capacitor network defines a first charge-transfer path leading to said port and wherein said second capacitor network defines a second charge-transfer path leading to said port, said second charge-transfer path differing from said first charge-transfer path.

11. The apparatus of claim 5 , wherein said switched-capacitor circuit comprises first and second terminals that are at first and second voltages, said second voltage being less than said first voltage, wherein each switch in said set of switches is configured to be able to sustain a voltage that is no greater than said first voltage and no less than said second voltage, wherein said apparatus further comprises a disconnect switch that connects to said first terminal.

12. The apparatus of claim 5 , wherein said wherein said fault-control circuitry is configured to monitor current at phase nodes of said switched-capacitor circuit, wherein said phase node connects to cathodes of said capacitors.

13. The apparatus of claim 5 , wherein said fault-control circuitry is configured to respond to said fault upon receiving a signal indicative of detection of said fault.

14. The apparatus of claim 1 , wherein said fault-control circuitry is configured to detect a fault based on polarities of currents at phase nodes of said switched-capacitor circuit.

15. The apparatus of claim 1 , wherein said fault-control circuitry is configured to detect a fault based on polarities of currents at phase nodes of said switched-capacitor circuit.

16. The apparatus of claim 1 , wherein said fault-control circuitry comprises logic circuitry having a logical state that transitions in response to detection of a fault.

17. The apparatus of claim 1 , wherein said fault-control circuitry comprises measurement circuitry that is configured to compare a reference value of an electrical parameter with a measured value of said electrical parameter.

18. The apparatus of claim 1 , wherein said fault-control circuitry comprises measurement circuitry for detecting a fault.