Bypass switching arrangement for series connected switched capacitor regulators
A feedback system that can control hybrid regulator topologies that have multiple converters or regulators connected in series is described. The hybrid regulator can include at least two regulators: a switched inductor regulator and a switched-capacitor regulator. The feedback system can simplify feedback design for the hybrid regulator that can include multiple converter stages and can control the feedback to improve the efficiency of a hybrid regulator.
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.
17. A voltage regulator system comprising:
at least two switched-capacitor voltage converters arranged in series between an input voltage and an output voltage, wherein the least two switched-capacitor voltage converters include:
a first switched-capacitor voltage converter having an input and an output; and
a second switched-capacitor voltage converter having an input and an output, wherein the input of the second switched-capacitor converter is connected to the output of the first switch-capacitor voltage converter;
at least two bypass switches, wherein the at least two bypass switches includes:
a first switch having a first side directly connected to the input of the first switched-capacitor voltage converter, and having a second side directly connected to the output of the first switched-capacitor voltage converter; and
a second switch having a first side directly connected to the input of the second switched-capacitor voltage converter, and having a second side directly connected to the output of the second switched-capacitor voltage converter,
wherein the at least two bypass switches are controlled to dynamically bypass the second voltage converter without bypassing the first voltage converter.
18. The voltage regulator system of claim 17 , wherein the first switched-capacitor voltage converter comprises a reconfigurable converter.
19. The voltage regulator system of claim 17 , further comprising a controller configured to control the switching of the at least two bypass switches.
20. The voltage regulator system of claim 19 , wherein the controller uses a lookup table to determine whether each of the at least two bypass switches should be on or off.
21. The voltage regulator system of claim 19 , wherein the controller is part of a feedback system.
22. A voltage regulator system comprising:
at least three switched-capacitor voltage converters arranged in series between an input voltage and an output voltage, wherein the least three switched-capacitor voltage converters include:
a first switched-capacitor voltage converter having an input and an output;
a second switched-capacitor voltage converter having an input and an output, wherein the input of the second switched-capacitor converter is connected to the output of the first switch-capacitor voltage converter; and
a third switched-capacitor voltage converter having an input and an output, wherein the input of the third switched-capacitor converter is connected to the output of the second switch-capacitor voltage converter; and
a bypass switch having a first side directly connected to the input of the second switched-capacitor voltage converter, and having a second side directly connected to the output of the third switched-capacitor voltage converter,
wherein the bypass switch is controlled to dynamically bypass the second voltage converter and the third voltage converter without bypassing the first voltage converter.
23. The voltage regulator system of claim 22 , wherein the first switched-capacitor voltage converter comprises a reconfigurable converter.
24. The voltage regulator system of claim 22 , further comprising a controller configured to control the switching of the bypass switch.
25. The voltage regulator system of claim 24 , wherein the controller uses a lookup table to determine whether the bypass switch should be on or off.
26. The voltage regulator system of claim 24 , wherein the controller is part of a feedback system.