Feedback control for hybrid regulator including a buck converter and a switched capacitor converter

1. A voltage regulator system comprising:

a hybrid regulator configured to convert an input voltage to an output voltage, wherein the hybrid regulator comprises a plurality of voltage regulators including at least a switched-inductor regulator and a switched-capacitor regulator,

wherein the switched-inductor regulator is configured to provide a non-zero amount of charge for a first portion of a first switching period and deliver no charge in a second portion of the first switching period until a subsequent cycle, thereby providing a first predetermined amount of charge per the first switching period, and

wherein the switched-capacitor regulator is configured to provide a second predetermined amount of charge per a second switching period; and

a first feedback system configured to:

compare the output voltage to a reference voltage to determine a first operating frequency for the switched-inductor regulator;

determine a second operating frequency for the switched-capacitor regulator based on the first predetermined amount of charge provided by the switched-inductor regulator per the first switching period and the second predetermined amount of charge per the second switching period;

cause the switched-inductor regulator to operate at the first operating frequency, and

cause the switched-capacitor regulator to operate at the second operating frequency; and

a second feedback system that is configured to determine a difference between a parasitic voltage drop and a target voltage drop of the switched-capacitor regulator and cause the switched-inductor regulator to adjust current provided to the switched-capacitor regulator based on the difference.

2. The voltage regulator system of claim 1 , wherein the first feedback system is configured to cause the switched-inductor regulator to operate at the first operating frequency by providing a first periodic signal having the first operating frequency to the switched-inductor regulator.

3. The voltage regulator system of claim 2 , wherein the first feedback system comprises a frequency divider that is configured to receive a second periodic signal generated by the feedback control and to generate the first periodic signal having the first operating frequency, and wherein the feedback system is configured to provide the second periodic signal to the switched-capacitor regulator.

4. The voltage regulator system of claim 1 , wherein the switched-inductor regulator comprises a multi-phase switched-inductor regulator having a plurality of regulator cells, and wherein the first feedback system is configured to cause the switched-inductor regulator to operate at the first operating frequency by providing a plurality of periodic signals having the first operating frequency to the switched-inductor regulator, wherein the plurality of periodic signals are out-of-phase from one another.

5. The voltage regulator system of claim 1 , wherein the first feedback system comprises a feedback control that is configured to generate a first periodic signal, based on the reference voltage and the output voltage, having the second operating frequency.

6. The voltage regulator system of claim 1 , wherein the second feedback system is configured to cause the switched-inductor regulator to adjust the current provided to the switched-capacitor regulator by adjusting one or more of the first switching period, an active period, and a duty cycle D of the switched-inductor regulator.

7. The voltage regulator system of claim 1 , wherein the first operating frequency is a fraction of the second operating frequency.

8. The voltage regulator system of claim 1 , further comprising a plurality of bypass switches, wherein one of the bypass switches is configured to couple an input node of a first voltage regulator and an output node of a second voltage regulator in the hybrid regulator.

9. An electronic system comprising:

a load chip comprising a power domain, wherein the power domain comprises an input voltage terminal and a ground terminal; and

a voltage regulator system of claim 1 , wherein the voltage regulator system is configured to provide the output voltage of the hybrid regulator to the input voltage terminal of the load chip.

10. A method of providing an output voltage based on an input voltage, the method comprising:

providing a hybrid regulator configured to convert the input voltage to the output voltage, wherein the hybrid regulator comprises a plurality of voltage regulators including at least a switched-inductor regulator and a switched-capacitor regulator, wherein the switched-inductor regulator is configured to provide a non-zero amount of charge for a first portion of a first switching period and deliver no charge in a second portion of the first switching period until a subsequent cycle of the switched-inductor regulator, and wherein the switched-capacitor regulator is configured to provide a second predetermined amount of charge per a second switching period; and

comparing, at a first feedback system, output voltage to a reference voltage to determine a first operating frequency for the switched-inductor regulator;

determining, by the first feedback system, a second operating frequency for the switched-capacitor regulator based on the first predetermined amount of charge provided by the switched-inductor regulator per the first switching period and the second predetermined amount of charge provided by the switched-capacitor regulator per a second switching period;

causing, by the first feedback system, the switched-inductor regulator to operate at the first operating frequency;

causing, by the first feedback system, the switched-capacitor regulator to operate at the second operating frequency;

determine, by a second feedback system, a difference between a parasitic voltage drop and a target voltage drop of the switched-capacitor regulator and cause the switched-inductor regulator to adjust current provided to the switched-capacitor regulator based on the difference.

11. The method of claim 10 , wherein causing the switched-inductor regulator to operate at the first operating frequency comprises providing a first periodic signal having the first operating frequency to the switched-inductor regulator.

12. The method of claim 11 , further comprising:

receiving, at a frequency divider in the first feedback system, the second periodic signal generated by the feedback control;

generating, by the frequency divider, the first periodic signal having the first operating frequency; and

providing the second periodic signal to the switched-capacitor regulator.

13. The method of claim 10 , wherein the switched-inductor regulator comprises a multi-phase switched-inductor regulator having a plurality of regulator cells, and wherein causing the switched-inductor regulator to operate at the first operating frequency comprises providing a plurality of periodic signals having the first operating frequency to the switched-inductor regulator, wherein the plurality of periodic signals are out-of-phase from one another.

14. The method of claim 10 , further comprising generating, at a feedback control in the first feedback system, a first periodic signal having the second operating frequency based on the reference voltage and the output voltage.

15. The method of claim 10 , wherein causing the switched-inductor regulator to adjust the current provided to the switched-capacitor regulator by adjusting one or more of: the first switching period, an active period, and/or a duty cycle D of the switched-inductor regulator.

16. The method of claim 10 , wherein the hybrid regulator system comprises a plurality of bypass switches, wherein one of the bypass switches is configured to couple an input node and an output node of the one of the voltage regulators in the hybrid regulator.