Slew-controlled switched capacitors for AC-DC applications
In a power converter, a regulator that receives a first voltage couples to a switched-capacitor converter that provides a second voltage. Slew-control circuitry controls slew rate within the switched-capacitor converter during operation thereof. A controller controls the operation of both the regulator and the switched-capacitor converter.
1. An apparatus comprising slew-control circuitry, a regulator, a switched-capacitor converter, and a controller, wherein said regulator is to receives a first voltage and said switched-capacitor converter is to provide a second voltage, wherein said regulator and said switched-capacitor converter are coupled to each other, wherein said controller is to control said regulator and said switched-capacitor converter, wherein said slew-control circuitry is to control a slew rate of said second voltage, wherein said switched-capacitor converter comprises a plurality of capacitors, first switches, and second switches, wherein closing said first switches and opening said second switches arranges said capacitors into a first state, wherein closing said second switches and opening said first switches arranges said capacitors into a second state, and wherein said controller causes said switched-capacitor converter to transition between said first state and said second state, thereby transferring charge between capacitors of said switched-capacitor converter.
2. The apparatus of claim 1 , further comprising bypass switches, wherein said switched-capacitor converter comprises a first stage and a second stage, wherein said bypass switches are for switching said first and second stages into or out of the switched-capacitor circuit, thereby achieving different voltage conversion ratios.
3. The apparatus of claim 1 , wherein said switched-capacitor converter comprises a plurality of stages and a plurality of bypass switches, wherein the stages can be switched into or out of said switched-capacitor circuit during operation thereof thereby achieving different voltage conversion ratios, and wherein the bypass switches are for switching said stages into or out of said switched-capacitor converter.
4. The apparatus of claim 1 , wherein said switched-capacitor converter is a single-stage switched-capacitor circuit, wherein the switches of the first switch set and the switches of the second switch set are to transition between switch states so as to cause said switched-capacitor circuit to operate at different voltage conversion ratios.
5. The apparatus of claim 1 , wherein said controller comprises a primary side section and a secondary side section, wherein said primary side section is to control passage of current through a primary winding, wherein said secondary side section controls said switched-capacitor converter, and wherein said primary and secondary side sections of said controller are isolated from each other.
6. The apparatus of claim 1 , wherein said switched-capacitor converter comprises a first stage and a second stage and wherein each of said first and second stages is a voltage divider.
7. The apparatus of claim 2 , wherein said bypass switches comprise a first bypass switch and a second bypass switch and wherein said second bypass switch blocks flow of reverse current when said first bypass switch is closed.
8. The apparatus of claim 1 , wherein said slew-control circuitry comprises a charge reservoir for controlling slew rate of a switch to which said slew-control circuitry is coupled.
9. The apparatus of claim 1 , wherein said slew-control circuitry comprises a capacitor and a resistor through which to discharge said capacitor when controlling slew rate.
10. The apparatus of claim 1 , wherein said slew-control circuitry further comprises a comparator that halts slew control upon occurrence of a condition.
11. The apparatus of claim 1 , wherein said slew-control circuitry is reconfigurable.
12. The apparatus of claim 1 , wherein said slew-control circuitry is programmable.
13. The apparatus of claim 1 , further comprising a bridge rectifier disposed to transform an AC voltage into said first voltage.
14. The apparatus of claim 1 , further comprising a travel adapter, wherein said regulator, said switched-capacitor converter, said slew-control circuitry, and said controller are disposed in said travel adapter.
15. The apparatus of claim 1 wherein said switched-capacitor converter is one that causes charge stored in at least one capacitor of said switched-capacitor converter to change by causing at least some charge that is stored in said at least one capacitor to be passed through an element that is not a capacitor.
16. The apparatus of claim 1 , wherein said regulator is a magnetically-isolated regulator.
17. The apparatus of claim 1 , wherein said regulator comprises a non-isolated regulator.
18. The apparatus of claim 1 , wherein said regulator comprises a galvanically-isolated regulator.
19. The apparatus of claim 1 , wherein said regulator comprises a first functional component and a second functional component, wherein said first and second functional components are to communicate energy therebetween in the absence of electrical conduction therebetween.
20. The apparatus of claim 1 , wherein said controller is to receive one or more feedback signals from one or more of said regulator and said switched-capacitor converter.