# US 10,770,909 B2 · Short circuit protection for data interface charging > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,909 B2 - Document ID: US10770909B2 - Status: Granted - Kind: B2 - Application number: 15/709,408 - Filed: 2017-09-19 - Published: 2018-01-11 - Granted: 2020-09-08 - Earliest claimed: 2015-03-20 - Assignees: Dialog Semiconductor GmbH - Applicants: Dialog Semiconductor Inc. - Inventors: Jianming Yao; Yong Li; Dickson Wong - Web page: https://patentgrep.com/patent/US10770909B2 ## CPC - H02M 3/33523: {with galvanic isolation between input and output of both the power stage and the feedback loop} - H02H 7/1227: {responsive to abnormalities in the output circuit, e.g. short circuit} - H02J 7/04: Regulation of charging current or voltage - H02J 7/64: against overvoltage - H02J 7/00: Circuit arrangements for charging or discharging batteries or for supplying loads from batteries - H02M 3/33592: {having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer} - Y02B 40/00: Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers - 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) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract A switching power converter is provided with an overvoltage protection circuit that monitors the differential data signal voltages in a data interface such as a USB data interface powering a load device to detect soft short conditions. ## Claims ### Claim 1 A system, comprising: a flyback converter including a transformer having a primary side and a second side, the flyback converter having a primary-side controller configured to regulate a switching of a primary-side power switch to power a load device through a power supply voltage carried on a power supply voltage pin in an USB data interface that includes a data signal carried on a pair of data pins separate from the power supply terminal; a secondary-side fast charge interface configured to enumerate the load device using the data signal to determine whether the load device supports an increased output voltage level that is greater than a default level for the output voltage, and wherein the secondary-side fast charge interface is configured to signal the primary-side controller to increase the power supply voltage to the increased output voltage level; and a secondary-side overvoltage protection circuit including a comparator configured to compare a voltage for the data signal to a reference voltage to assert an overvoltage alarm signal to the primary-side controller responsive to the voltage for the data signal being greater than the reference voltage, wherein the primary-side controller is configured to reduce the power supply voltage to the default level responsive to an assertion of the overvoltage alarm signal. ### Claim 2 (depends on 1) The system of claim 1, wherein the data signal comprises at least one pair of differential data signals. ### Claim 3 (depends on 1) The system of claim 1, wherein the secondary-side overvoltage protection circuit further comprises a bandgap reference configured to provide the reference voltage to the comparator. ### Claim 4 (depends on 1) The system of claim 1, wherein the secondary-side overvoltage protection circuit further comprises a pair of voltage dividers, and wherein the comparator is configured to select the reference voltage from the pair of voltage dividers. ### Claim 5 A method, comprising: enumerating a load device through a secondary-side fast charge interface of a flyback converter using a differential data signal carried on a pair of data pins to determine whether the load device supports an increased output voltage level for a power supply voltage supplied on a power supply voltage pin in a data interface for the flyback converter; in the flyback converter, increasing the power supply voltage from a default level to the increased output voltage level and powering the load device through the data interface with the power supply voltage at the increased output voltage level; while powering the load device with the power supply voltage at the increased output voltage level, comparing a voltage of the differential data signal to a reference voltage; asserting an overvoltage alarm signal responsive to the voltage of the differential data signal exceeding the reference voltage; and reducing the power supply voltage to the default level responsive to an assertion of the overvoltage alarm signal. ### Claim 6 (depends on 5) The method of claim 5, wherein the data interface is a USB interface. ### Claim 7 (depends on 6) The method of claim 6, further comprising dividing the voltage of the differential data signal through a voltage divider to produce a divided voltage, wherein comparing the voltage of the differential data signal comprises comparing the divided voltage. ### Claim 8 (depends on 6) The method of claim 6, wherein the reference voltage comprises a bandgap reference voltage.