# US 12,009,746 B2 · DC-DC converter based on piezoelectric resonator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,746 B2 - Document ID: US12009746B2 - Status: Granted - Kind: B2 - Application number: 17/605,255 - Filed: 2020-06-12 - Published: 2022-06-23 - Granted: 2024-06-11 - Earliest claimed: 2019-06-13 - Assignees: Massachusetts Institute of Technology - Applicants: Massachusetts Institute of Technology - Inventors: David J. Perreault; Jessica Boles; Joshua Piel - Web page: https://patentgrep.com/patent/US12009746B2 ## CPC - H02M 3/155: using semiconductor devices only - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02M 3/06: using resistors or capacitors, e.g. potential divider - H02M 1/0058: {by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826)} - H02M 1/0095: {Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck} - 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 dc-dc converter can include a plurality of switches, a piezoelectric resonator (PR) for power stage energy storage, and a means for controlling one or more switching sequences. The switches operate in accordance with the switching sequences to transfer energy from the input to the output via the PR while providing low-loss resonant soft-charging of the PR's capacitance. The switching sequences include: connected stages in which a first and second PR terminals are both connected to one of the input, the output, or the other PR terminal; and open stages in which at least one of the first or second PR terminal is not connected by a closed switch to one of the input, the output, or the other PR terminal. ## Claims ### Claim 1 A dc-dc converter having an input and an output comprising: a plurality of switches; a piezoelectric resonator (PR) having a first terminal and a second terminal, wherein the plurality of switches operate in accordance with one or more switching sequences to transfer energy from the input to the output via the PR while providing low-loss resonant soft-charging of a capacitance of the PR, the switching sequences including: connected stages in which the first PR terminal and the second PR terminal are both connected to one of the input, the output, or the other PR terminal, and open stages in which at least one of the first PR terminal or the second PR terminal is not connected by a closed switch of the plurality of switches to one of the input, the output, or the other PR terminal; and means, coupled to the plurality of switches, for controlling the switching sequences, wherein at least one of the switching sequences includes at least six stages alternating between connected stages and open stages in which the connected stages each comprise a connection of the first PR terminal or the second PR terminal to one of the input or the output and a connection of the other PR terminal to a different node of the dc-dc converter. ### Claim 2 (depends on 1) The dc-dc converter of claim 1, wherein at least one of the switching sequences includes at least six stages alternating between connected stages and open stages in which one of the connected stages comprises a zero stage in which the first PR terminal and the second PR terminal are connected. ### Claim 3 (depends on 1) The dc-dc converter of claim 1, wherein at least one of the switching sequences provides zero-voltage switching (ZVS) of each of the plurality of switches. ### Claim 4 (depends on 3) The dc-dc converter of claim 3, wherein the at least one of the switching sequences that provides ZVS includes at least one open stage during which the first and second PR terminals change voltage is split into two sections. ### Claim 5 (depends on 1) The dc-dc converter of claim 1, wherein at least one of the switching sequences includes at least eight stages. ### Claim 6 (depends on 1) The dc-dc converter of claim 1, wherein the switching sequences include one or more switching sequences that has exactly one span of positive PR resonant current and exactly one span of negative PR resonant current. ### Claim 7 (depends on 1) The dc-dc converter of claim 1, wherein the PR is disposed within a switched capacitor (SC) converter comprising one or more capacitors for energy storage. ### Claim 8 (depends on 7) The dc-dc converter of claim 7, wherein the switching sequences utilize both the SC converter capacitors and the PR as energy transfer components. ### Claim 9 A dc-dc converter having an input, an output, and an energy storage element consisting essentially of a piezoelectric resonator (PR), the converter comprising: a plurality of switching elements; and a piezoelectric resonator (PR) configured for power stage energy storage, the PR having first and second terminals selectively coupled to the plurality of switching elements, wherein the plurality of switching elements are arranged to operate in accordance with one or more switching sequences that provide low-loss resonant soft charging of a capacitance of the PR, wherein at least one of the switching sequences includes at least six stages alternating between connected stages and open stages in which the connected stages each comprise a connection of the first PR terminal or the second PR terminal to one of the input or the output and a connection of the other PR terminal to a different node of the PR converter. ### Claim 10 (depends on 9) The converter of claim 9, wherein at least one of the switching elements includes a unidirectional-blocking switch. ### Claim 11 (depends on 9) The converter of claim 9, wherein the plurality of switching elements includes four unidirectional-blocking switches. ### Claim 12 (depends on 11) The converter of claim 11, wherein the unidirectional-blocking switches are provided as field effect transistors. ### Claim 13 (depends on 11) The converter of claim 11, wherein the unidirectional-blocking switches are provided as metal oxide semiconductor field effect transistors (MOSFETs). ### Claim 14 (depends on 9) The converter of claim 9, wherein at least one of the switching elements includes a diode switch. ### Claim 15 (depends on 9) The dc-dc converter of claim 9 further comprising: a switching controller configured to operate the plurality of switching elements according to the one or more switching sequences. ### Claim 16 A two-stage dc-dc converter comprising: a piezoelectric-resonator (PR) converter stage having an input, an output, an energy storage element consisting essentially of a PR and a plurality of switches, the PR having first and second terminals selectively coupled to the plurality of switches, the plurality of switches arranged to operate in accordance with one or more switching sequences that utilize the PR as an energy transfer component, wherein at least one of the switching sequences includes at least six stages alternating between connected stages and open stages in which the connected stages each comprise a connection of the first PR terminal or the second PR terminal to one of the input or the output and a connection of the other PR terminal to a different node of the PR converter; and a switched capacitor (SC) converter stage coupled to the PR converter stage in a cascaded arrangement.