Resonant switched-capacitor converter

1. A resonant switched-capacitor converter, configured to convert an input voltage on an input terminal of the resonant switched-capacitor converter into an output voltage on an output terminal of the resonant switched-capacitor converter, wherein the resonant switched-capacitor converter comprises:

a first resonant tank;

a second resonant tank;

at least one non-resonant capacitor; and

a connection control circuit, coupled to the input terminal, the output terminal, the first resonant tank, the second resonant tank and the at least one non-resonant capacitor, configured to control connections of the first resonant tank, the second resonant tank and the at least one non-resonant capacitor;

wherein during a first phase, a first terminal of the first resonant tank is coupled to a reference terminal via a path without any capacitor, and a first terminal of the second resonant tank is coupled to the output terminal; and during a second phase, the first terminal of the first resonant tank is coupled to the output terminal, and the first terminal of the second resonant tank is coupled to the reference terminal via a path without any capacitor.

2. The resonant switched-capacitor converter of claim 1 , wherein during the first phase, a second terminal of the first resonant tank is coupled to the output terminal, and a second terminal of the second resonant tank is coupled to a first terminal of the non-resonant capacitor; and during the second phase, the second terminal of the first resonant tank is coupled to a second terminal of the non-resonant capacitor, and the second terminal of the second resonant tank is coupled to the output terminal.

3. The resonant switched-capacitor converter of claim 1 , wherein during the first phase, a first terminal of the non-resonant capacitor is coupled to a second terminal of the second resonant tank, and a second terminal of the non-resonant capacitor is coupled to the input terminal; and during the second phase, the first terminal of the non-resonant capacitor is coupled to the reference terminal, and the second terminal of the non-resonant capacitor is coupled to a second terminal of the first resonant tank.

4. The resonant switched-capacitor converter of claim 1 , wherein a voltage across the non-resonant capacitor is 0.5 times the input voltage.

5. The resonant switched-capacitor converter of claim 1 , wherein the connection control circuit comprises a plurality of switches, a portion of the switches are controlled by a first control signal, and another portion of the switches are controlled by a second control signal.

6. The resonant switched-capacitor converter of claim 5 , wherein the first control signal and the second control signal are non-overlapping control signals; and one of the first control signal and the second control signal has a fifty percent or less duty cycle, and another of the first control signal and the second control signal has a duty cycle less than fifty percent.

7. The resonant switched-capacitor converter of claim 5 , wherein a frequency of each of the first control signal and the second control signal is equal to a resonant frequency corresponding to the first resonant tank and the second resonant tank.

8. The resonant switched-capacitor converter of claim 1 , wherein each resonant tank of the first resonant tank and the second resonant tank comprises a resonant inductor and a resonant capacitor, and a resonant frequency corresponding to the each resonant tank is determined by the resonant inductor and the resonant capacitor.

9. The resonant switched-capacitor converter of claim 8 , wherein a voltage across the resonant capacitor is 0.25 times the input voltage.

10. A resonant switched-capacitor converter, configured to convert an input voltage on an input terminal of the resonant switched-capacitor converter into an output voltage on an output terminal of the resonant switched-capacitor converter, wherein the resonant switched-capacitor converter comprises:

a first resonant tank;

a second resonant tank;

at least one non-resonant capacitor; and

a connection control circuit, coupled to the input terminal, the output terminal, the first resonant tank, the second resonant tank and the at least one non-resonant capacitor, configured to control connections of the first resonant tank, the second resonant tank and the at least one non-resonant capacitor;

wherein the connection control circuit comprises:

a first switch, directly connected between a first terminal of the non-resonant capacitor and a second terminal of the second resonant tank; and

a second switch, directly connected between a second terminal of the non-resonant capacitor and a second terminal of the first resonant tank, wherein the first terminal of the non-resonant capacitor is different from the second terminal of the non-resonant capacitor;

wherein during a first phase, the first terminal of the non-resonant capacitor is coupled to the second terminal of the second resonant tank via the first switch; and during a second phase, the second terminal of the non-resonant capacitor is coupled to the second terminal of the first resonant tank via the second switch.

11. The resonant switched-capacitor converter of claim 10 , wherein during the first phase, the second terminal of the first resonant tank is coupled to the output terminal; and during the second phase, the second terminal of the second resonant tank is coupled to the output terminal.

12. The resonant switched-capacitor converter of claim 10 , wherein during the first phase, the second terminal of the non-resonant capacitor is coupled to the input terminal; and during the second phase, the first terminal of the non-resonant capacitor is coupled to a reference terminal.

13. The resonant switched-capacitor converter of claim 10 , wherein a voltage across the non-resonant capacitor is 0.5 times the input voltage.

14. The resonant switched-capacitor converter of claim 10 , wherein the connection control circuit comprises a plurality of switches, a portion of the switches are controlled by a first control signal, and another portion of the switches are controlled by a second control signal.

15. The resonant switched-capacitor converter of claim 14 , wherein the first control signal and the second control signal are non-overlapping control signals; and one of the first control signal and the second control signal has a fifty percent or less duty cycle, and another of the first control signal and the second control signal has a duty cycle less than fifty percent.

16. The resonant switched-capacitor converter of claim 14 , wherein a frequency of each of the first control signal and the second control signal is equal to a resonant frequency corresponding to the first resonant tank and the second resonant tank.

17. The resonant switched-capacitor converter of claim 10 , wherein each resonant tank of the first resonant tank and the second resonant tank comprises a resonant inductor and a resonant capacitor, and a resonant frequency corresponding to the each resonant tank is determined by the resonant inductor and the resonant capacitor.

18. The resonant switched-capacitor converter of claim 17 , wherein a voltage across the resonant capacitor is 0.25 times the input voltage.