# US 2021/0281179 A1 · Hybrid DC-DC Power Converter with Small Voltage Conversion Ratio

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- Number: US 2021/0281179 A1
- Document ID: US20210281179A1
- Status: Published application
- Kind: A1
- Application number: 17/308,271
- Filed: 2021-05-05
- Published: 2021-09-09
- Earliest claimed: 2019-05-03
- Assignees: Dialog Semiconductor (UK) Limited
- Applicants: Dialog Semiconductor (UK) Limited
- Inventors: Francesco Cannillo; Nicola Macri
- Web page: https://patentgrep.com/patent/US20210281179A1

## CPC

- H02M 3/1584: {with a plurality of power processing stages connected in parallel}
- H02M 1/14: Arrangements for reducing ripples from DC input or output
- H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps}
- H02M 1/007: {Plural converter units in cascade (push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826)}
- H02M 1/009: {having two or more independently controlled outputs (for DC-DC converter with intermediate AC H02M3/33561)}
- H02M 1/0095: {Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck}
- H02M 3/158: including plural semiconductor devices as final control devices for a single load
- H02M 3/1586: {switched with a phase shift, i.e. interleaved}
- Y02B 70/10: Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
- 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)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A power converter and method to provide a small conversion ratio between an input and an output voltage. The power converter has an inductor coupled to the input port of the power converter. The power converter has a first stage with an input node; a first switch; a second switch; a third switch coupled to the second switch of the first stage and to a reference potential; and a flying capacitor coupled to the input node. The power converter also has a second stage with an input node; a first switch coupled to the input node of the second stage and to the output port of the power converter; a second switch coupled to the input node of the first stage; a third switch coupled to the second switch of the second stage and to the reference potential; and a flying capacitor coupled to the inductor.

## Claims

### Claim 1

1) A power converter configured to convert an input voltage at an input port to an output voltage at an output port; wherein the power converter comprises,
an inductor coupled to the input port of the power converter;
a first stage comprising
an input node;
a first switch coupled to the input node of the first stage and to the output port of the power converter;
a second switch coupled to the output port of the power converter ;
a third switch coupled to the second switch of the first stage and to a reference potential; and
a flying capacitor coupled to the input node and to an intermediate node between the second switch and the third switch of the first stage;
a second stage comprising
an input node;
a first switch coupled to the input node of the second stage and to the output port of the power converter;
a second switch coupled to the input node of the first stage;
a third switch coupled to the second switch of the second stage and to the reference potential; and
a flying capacitor coupled to the inductor and to an intermediate node between the second switch and the third switch of the second stage; and
a control unit configured to
determine a target voltage conversion ratio between the output voltage and the input voltage; and
deactivate or activate the first stage in dependence of the target voltage conversion ratio,
wherein the control unit is configured to deactivate a particular stage by
maintaining permanently closed the first switch and the third switch of the particular stage; and
maintaining permanently open the second switch of the particular stage.

### Claim 2 (depends on 1)

2) The power converter of claim 1, wherein
the control unit is configured to operate the first and second stage alternatingly and repeatedly in a first and a second phase;
in the first phase, the first switches and the third switches of the first and second stage are closed, and the second switches of the first and second stage are open; and
in the second phase, the first switches and the third switches of the first and second stage are open, and the second switches of the first and second stage are closed.

### Claim 3 (depends on 2)

3) The power converter of claim 2, wherein the control unit is configured to set a duration of the first phase relative to a duration of the second phase, in order to set a voltage conversion ratio between the output voltage and the input voltage of the power converter.

### Claim 4 (depends on 2)

4) The power converter of claim 2, wherein the control unit is configured to repeat the first and the second phase at a cycle rate.

### Claim 5 (depends on 1)

5) The power converter of claim 1, wherein
the power converter comprises N stages enumerated as n=1, . . . , N, with N>2;
the first stage is the stage with n=1;
the second stage is the stage with n=2;
the nth stage comprises
an input node;
a first switch coupled to the input node of the nth stage and to the output port of the power converter;
a second switch coupled to the input node of the (n−1)th stage;
a third switch coupled to the second switch of the nth stage and to the reference potential; and
a flying capacitor coupled to the second switch of the (n+1)th stage and to an intermediate node between the second switch and the third switch of the nth stage; and
the flying capacitor of the Nth stage is directly coupled to the inductor.

### Claim 6 (depends on 1)

6) The power converter of claim 1, wherein
the control unit is configured to increase the number of active stages as the target voltage conversion ratio decreases, or vice versa; and
the stages are deactivated starting with stage n=1, and according to increasing values of n.

### Claim 7 (depends on 6)

7) The power converter of claim 6, wherein the control unit is configured to
determine the number of active stages for the target voltage conversion ratio using a look-up table; and
operates the power converter with the determined number of active stages.

### Claim 8

8) A method for operating a power converter, wherein the power converter comprises
an inductor coupled to the input port of the power converter;
a first stage comprising an input node; a first switch coupled to the input node of the first stage and to an output port of the power converter; a second switch coupled to the output port of the power converter; a third switch coupled to the second switch of the first stage and to a reference potential; and a flying capacitor coupled to the input node and to an intermediate node between the second switch and the third switch of the first stage; and
a second stage comprising an input node; a first switch coupled to the input node of the second stage and to the output port of the power converter; a second switch coupled to the input node of the first stage; a third switch coupled to the second switch of the second stage and to the reference potential; and a flying capacitor coupled to the inductor and to an intermediate node between the second switch and the third switch of the second stage;
wherein the method comprises
operating the first and second stage alternatingly in a first and a second phase; wherein in the first phase, the first switches and the third switches of the first and second stage are closed, and the second switches of the first and second stage are open; and wherein in the second phase, the first switches and the third switches of the first and second stage are open, and the second switches of the first and second stage are closed;
determining a target voltage conversion ratio between the output voltage and the input voltage; and
deactivating or activating the first stage in dependence of the target voltage conversion ratio; and
wherein deactivating a particular stage comprises
maintaining permanently closed the first switch and the third switch of the particular stage; and
maintaining permanently open the second switch of the particular stage.