System and method for resonant buck regulator

1. A system, comprising:

a buck regulator circuit including a first switch, a second switch, and a load current; and

a resonant tank circuit connected to an input of both the first switch and the second switch of the buck regulator circuit, wherein the resonant tank circuit comprises an inductor, a first capacitor and a second capacitor configured to form the resonant tank circuit to jointly switch both the first switch and the second switch of the buck regulator to reduce a switching power from a switching frequency of the first switch and the second switch, wherein the inductor resonates with a first gate capacitance of the first capacitor and a second gate capacitance of the second capacitor, wherein the switching frequency is at least 2 GHz when the load current is in a range of 10 mA to 40 mA.

2. The system of claim 1 , where the first switch comprises an NMOS switch and the second switch comprises a PMOS switch.

3. The system of claim 1 , further comprising a slew rate recovery circuit connected with the buck regulator circuit.

4. The system of claim 3 , where the slew rate recovery circuit comprises separately adjusted timing of clock drivers with voltages through tunable capacitors.

5. The system of claim 1 , further comprising a digital duty cycle control circuit connected with the buck regulator circuit.

6. The system of claim 5 , where the digital duty cycle control circuit provides feedback control for voltage regulation to the buck regulator circuit.

7. The system of claim 1 , where the first capacitor connects with the second switch to boost switch transition and reduce energy loss.

8. The system of claim 1 , where the second capacitor connects with a gate of the first switch to shift down a voltage.

9. The system of claim 1 , wherein the resonant tank is housed in at least one of a mobile phone, a smart device, a wearable device, an Internet-of-Things device, a remote sensor and a biomedical device.

10. The system of claim 1 , further comprising a feedback loop for generating control voltages to the buck regulator circuit.

11. The system of claim 1 , further comprising a slew rate recovery circuits to improve switching transition speed to reduce power loss.

12. A system, comprising:

a buck regulator circuit including a first switch, a second switch, and a load current; and

a digital duty cycle control circuit connected with the buck regulator circuit, where the digital duty cycle control circuit provides feedback control to the buck regulator circuit for voltage regulation; and

a resonant tank circuit connected to an input of the buck regulator circuit, where the resonant tank circuit comprises an inductor, a first capacitor and a second capacitor to jointly switch both the first switch and the second switch of the buck regulator to reduce a switching power from a switching frequency of the first switch and the second switch, wherein the inductor resonates with a first gate capacitance of the first capacitor and a second gate capacitance of the second capacitor, wherein the switching frequency is at least 2 GHz when the load current is in a range of 10 mA to 40 mA.

13. The system of claim 12 , where the duty cycle control circuit comprises an up/down binary counter and a digital-to-analog converter.

14. The system of claim 13 , where the digital-to-analog converter comprises an R-2R digital-to-analog converter.

15. The system of claim 12 , further duty cycle control circuit generates control voltages to the buck regulator circuit.

16. The system of claim 12 , further comprising a slew rate recovery circuit connected with the duty cycle control circuit and the buck regulator circuit, where the slew rate recovery circuit comprises separately adjusted timing of clock drivers with voltages through tunable capacitors.