# US 10,483,837 B1 · Variable frequency modulation scheme based on current-sensing techniques for switched-capacitor DC-DC converters > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,837 B1 - Document ID: US10483837B1 - Status: Granted - Kind: B1 - Application number: 15/979,359 - Filed: 2018-05-14 - Published: 2019-11-14 - Granted: 2019-11-19 - Earliest claimed: 2018-05-14 - Assignees: Renesas Electronics America Inc. - Applicants: Renesas Electronics America Inc. - Inventors: Yen-Mo Chen - Web page: https://patentgrep.com/patent/US10483837B1 ## CPC - H02M 1/088: for the simultaneous control of series or parallel connected semiconductor devices - H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02M 7/4837: {Flying capacitor converters} - H02M 1/0032: {Control circuits allowing low power mode operation, e.g. in standby mode} - H02M 1/0048: {Circuits or arrangements for reducing losses (using snubbers H02M1/34)} - 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 The present embodiments are directed to an improved switched capacitor (SC) converter topology that does not include an inductor. In particular, the topology includes a ladder SC circuit configured as a cap divider, with a gate driving signal being generated to initiate the charging and discharging of the capacitor. In this specific topology, an unregulated output voltage is produced that is a certain fraction of an input voltage of a power source such as a battery. The present embodiments further include a variable frequency modulation (VFM) scheme based on the current-sensing techniques for the gate driving signal generation of the switched capacitor converter. ## Claims ### Claim 1 An apparatus for converting an input voltage at an input to an output voltage at an output, the apparatus comprising: a capacitor, wherein the capacitor is configured such that a charging and discharging of the capacitor transfers energy from the input to the output; switches configured to control the charging and discharging of the capacitor; a controller that controls a switching frequency of the switches based on a current associated with the transfer of energy from the input to the output; and a lookup table coupled to the controller, wherein the controller is configured to set the switching frequency based on the current using one or more entries in the lookup table, wherein the lookup table stores a plurality of different switching frequency values for a same given current value, and wherein the controller is configured to select a certain at least one of the plurality of different switching frequency values based on the current, and wherein the plurality of different switching frequency values for the same given current value correspond to a plurality of different performance metric values associated with the transfer of energy from the input to the output. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising a current sense resistor coupled to the controller that is configured to sense the current. ### Claim 3 (depends on 1) The apparatus of claim 1, further comprising a SENSEFET coupled to the controller that is configured to sense the current. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the controller includes a voltage controlled oscillator that is configured to control the switching frequency in accordance with a voltage based on the current. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the switches comprise FETs, and wherein the controller is coupled to provide gate driving signals to the gates of the FETs, the gate driving signals having the switching frequency. ### Claim 6 (depends on 5) The apparatus of claim 5, wherein the gate driving signals further have a duty cycle that is at least partially dependent on a ratio between the input voltage and the output voltage. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the capacitor is configured to transfer energy from the input to the output without use of an inductor. ### Claim 8 (depends on 1) The apparatus of claim 1, wherein the switches and the capacitor are configured in a ladder topology. ### Claim 9 (depends on 1) The apparatus of claim 1, further comprising a decoupling capacitor for use in charging the capacitor with the input voltage. ### Claim 10 (depends on 1) The apparatus of claim 1, further comprising an output capacitor for use in storing the output voltage as a result of the discharging of the capacitor. ### Claim 11 A method for converting an input voltage at an input to an output voltage at an output, the method comprising: charging and discharging a capacitor so as to transfer energy from the input to the output; operating switches to control the charging and discharging of the capacitor; controlling, by a controller, a switching frequency of the switches based on a current associated with the transfer of energy from the input to the output; and setting, by the controller, the switching frequency based on the current using one or more entries in a lookup table, wherein the lookup table stores a plurality of different switching frequency values for a same given current value, the method further comprising selecting a certain at least one of the plurality of different switching frequency values based on the current, and wherein the plurality of different switching frequency values for the same given current value correspond to a plurality of different performance metric values associated with the transfer of energy from the input to the output. ### Claim 12 (depends on 11) The method of claim 11, further comprising sensing the current using a current sense resistor coupled to the controller. ### Claim 13 (depends on 11) The method of claim 11, further comprising sensing the current using a SENSEFET coupled to the controller. ### Claim 14 (depends on 11) The method of claim 11, wherein the controller includes a voltage controlled oscillator, wherein controlling the switching frequency is performed in accordance with a voltage based on the current. ### Claim 15 (depends on 11) The method of claim 11, wherein the switches comprise FETs, the method further comprising providing, by the controller, gate driving signals to the gates of the FETs, the gate driving signals having the switching frequency. ### Claim 16 (depends on 15) The method of claim 15, wherein the gate driving signals further have a duty cycle that is at least partially dependent on a ratio between the input voltage and the output voltage. ### Claim 17 (depends on 1) The apparatus of claim 1, wherein the performance metric values comprise different efficiency values. ### Claim 18 (depends on 1) The apparatus of claim 1, wherein the performance metric values comprise different ripple values. ### Claim 19 (depends on 11) The method of claim 11, wherein the performance metric values comprise different efficiency values. ### Claim 20 (depends on 11) The method of claim 11, wherein the performance metric values comprise different ripple values.