# US 10,374,511 B2 · Switched capacitor DC-to-DC converter and power conversion control methods

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- Number: US 10,374,511 B2
- Document ID: US10374511B2
- Status: Granted
- Kind: B2
- Application number: 15/545,614
- Filed: 2016-01-29
- Published: 2018-01-18
- Granted: 2019-08-06
- Earliest claimed: 2015-01-29
- Assignees: The Regents of the University of California
- Applicants: The Regents of the University of California
- Inventors: Loai Galal Bahgat Salem; Patrick Mercier
- Web page: https://patentgrep.com/patent/US10374511B2

## CPC

- H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps}
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)

## Abstract

A scalable controller circuit that provides faster and simpler regulation of a DC-to-DC converter is provided. Unlike such prior techniques, preferred embodiments do not require any threshold-level generation circuitry or analog compensation circuitry. Preferred embodiments implement a simple control law that requires only a few digital gates. Preferred embodiments can therefore significantly reduce the overhead power consumption and area of the controller in DC-to-DC converters to new levels.

## Claims

### Claim 1

A DC-DC converter, comprising:
a plurality of capacitive converter cells that provide a plurality of conversion ratios; and
an all-digital binary search controller that dynamically switches through a plurality of modes using an outer coarse-grain controller search at a clock rate of the converter; and
fine grain control logic to search at a multiple of the clock rate of the converter and set a final conversion ratio using output of the converter as a voltage reference.

### Claim 2 (depends on 1)

The converter of claim 1, wherein the multiple of the clock rate is generated by an oscillator that is on-chip with the all-digital binary search controller.

### Claim 3 (depends on 1)

The converter of claim 1, further comprising a recursive ratio decoder that responds to the binary search controller and sets switches in the plurality of converter cells to a conversion ratio set by the binary search controller.

### Claim 4 (depends on 3)

The converter of claim 3, wherein the plurality of converter cells comprise 2:1 switching capacitive converters arranged as boundary cells and transfer cells.

### Claim 5 (depends on 3)

The converter of claim 3, wherein the fine grain control includes a comparator that compares a present stage power output to desired voltage level and the recursive ratio decoder configures into a larger binary ratio if the comparator determines that the present power stage has a lower than desired voltage and configures into a next lower resolution if the comparator determines that the power stage exceeds the desired voltage.

### Claim 6 (depends on 1)

The converter of claim 1, in one of a laptop computer, tablet or smart phone.

### Claim 7 (depends on 1)

The converter of claim 1, wherein the all-digital binary search controller and the fine grain control logic set switches to obtain a sequential circuit comprising an interconnected arrangement the plurality of capacitive converter cells to execute a control law.

### Claim 8

A method of performing voltage regulation of a DC-DC conversion from an input voltage to a desired output voltage by selectively configuring a plurality of converter cells using a controller having a comparator and a sequential logic, the method comprising: obtaining a target voltage ratio based on the input voltage and the desired output voltage with coarse control that selects a configuration of the plurality of converter cells, and refining the target voltage ratio within a predefined plurality converter conversion ratios by comparing voltage output to the desired output voltage at a higher rate of comparison than the coarse control and selecting a refined configuration of the plurality of converter cells.