# US 11,079,443 B2 · Switch fault detection techniques for 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 11,079,443 B2 - Document ID: US11079443B2 - Status: Granted - Kind: B2 - Application number: 16/231,008 - Filed: 2018-12-21 - Published: 2020-06-25 - Granted: 2021-08-03 - Earliest claimed: 2018-12-21 - Assignees: Analog Devices International Unlimited Company - Applicants: Analog Devices International Unlimited Company - Inventors: Hai Chen; Gregory J. Hughes - Web page: https://patentgrep.com/patent/US11079443B2 ## CPC - G01R 31/40: Testing power supplies (testing photovoltaic devices H02S50/10) - H02M 3/1582: {Buck-boost converters (H02M3/1584 takes precedence)} - G01R 31/50: Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections (testing of sparking plugs H01T13/58) - G01R 31/52: Testing for short-circuits, leakage current or ground faults - H02M 1/088: for the simultaneous control of series or parallel connected semiconductor devices - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 3/155: using semiconductor devices only - H02M 3/158: including plural semiconductor devices as final control devices for a single load - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 Using various techniques, each transistor in a DC-DC converter can have a corresponding voltage detector that can compare a difference of a first voltage at a first terminal of the transistor and a second voltage at a second terminal of the transistor to a threshold voltage. Then, based on at least one comparison, a controller can detect an open circuit or a short circuit in one or more of the transistors regardless of the direction of the load current in the DC-DC converter. ## Claims ### Claim 1 A circuit configured to detect an open circuit or a short circuit in a switched-mode DC-DC converter having a switching regulator regardless of a direction of a load current, the circuit comprising: a first voltage detector circuit coupled across a first transistor, the first voltage detector circuit including a first output and configured to compare a difference of a first reference voltage or an output voltage and a node voltage to a corresponding one of first and second threshold voltages; a second voltage detector circuit coupled across a second transistor, the second voltage detector circuit including a second output and configured to compare a difference of a second reference voltage and the node voltage to a corresponding one of first and second threshold voltages; and a controller coupled to corresponding control nodes of the first and second transistors to control operation of the first and second transistors, wherein the first output of the first voltage detector circuit is coupled to a first input of the controller, wherein the second output of the second voltage detector circuit is coupled to a second input of the controller, and wherein the controller is configured to detect an open circuit or a short circuit in at least one of the first transistor and the second transistor based on at least one of the comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 2 (depends on 1) The circuit of claim 1, wherein the first voltage detector circuit includes a first pair of comparator circuits, and wherein the second voltage detector circuit includes a second pair of comparator circuits. ### Claim 3 (depends on 2) The circuit of claim 2, wherein at least one of the comparator circuits includes a hysteresis comparator. ### Claim 4 (depends on 2) The circuit of claim 2, wherein one or both of the first pair of comparator circuits and the second pair of comparator circuits forms a window comparator circuit. ### Claim 5 (depends on 2) The circuit of claim 2, wherein at least one of the comparator circuits includes an enable input configured to receive an enable signal, wherein the enable signal is configured to be set to a first logic level after a predetermined time following application of a second logic level of a control signal to either the first transistor or the second transistor. ### Claim 6 (depends on 5) The circuit of claim 5, wherein the predetermined time is adjustable. ### Claim 7 (depends on 1) The circuit of claim 1, in combination with a buck DC-DC converter. ### Claim 8 (depends on 1) The circuit of claim 1, in combination with a boost DC-DC converter. ### Claim 9 (depends on 1) The circuit of claim 1, in combination with an inverting buck-boost DC-DC converter. ### Claim 10 (depends on 1) The circuit of claim 1, in combination with a non-inverting buck-boost DC-DC, converter. ### Claim 11 (depends on 10) The circuit of claim 10, wherein the node voltage is a first node voltage, the circuit further comprising: a third voltage detector circuit coupled across a third transistor, the third voltage detector circuit including a third output and configured to compare a difference of the second reference voltage and a second node voltage to a corresponding one of third and fourth threshold voltages; a fourth voltage detector circuit coupled across a fourth transistor, the fourth voltage detector circuit including a fourth output and configured to compare a difference of the output voltage and the second node voltage to a corresponding one of third and fourth threshold voltages, wherein the third output of the third voltage detector circuit is coupled to a third input of the controller, wherein the fourth output of the fourth voltage detector circuit is coupled to a fourth input of the controller, and wherein the controller is further configured to detect an open circuit or a short circuit in at least one of the third transistor and the fourth transistor based on at least one of the comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 12 (depends on 1) The circuit of claim 1, in combination with an H-bridge circuit. ### Claim 13 (depends on 12) The circuit of claim 12, wherein the node voltage is a first node voltage, the circuit further comprising: a third voltage detector circuit coupled across a third transistor, the third voltage detector circuit including a third output and configured to compare a difference of the second reference voltage and a second node voltage to a corresponding one of third and fourth threshold voltages; a fourth voltage detector circuit coupled across a fourth transistor, the fourth voltage detector circuit including a fourth output and configured to compare a difference of the first reference voltage and the second node voltage to a corresponding one of third and fourth threshold voltages, wherein the third output of the third voltage detector circuit is coupled to a third input of the controller, wherein the fourth output of the fourth voltage detector circuit is coupled to a fourth input of the controller, and wherein the controller is further configured to detect an open circuit or a short circuit in at least one of the third transistor and the fourth transistor based on at least one of the comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 14 (depends on 13) The method of claim 13, wherein the controller is coupled to corresponding controller nodes of third and fourth transistors and controls operation of the third and fourth transistors, and wherein the node voltage is a first node voltage, the method further comprising: comparing a difference across the third transistor of the second reference voltage and a second node voltage to a corresponding one of third and fourth threshold voltages; comparing a difference across the fourth transistor of the output voltage and the second node voltage to a corresponding one of third and fourth threshold voltages, detecting an open circuit or a short circuit in at least one of the third transistor and the fourth transistor based on at least one of the comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 15 (depends on 13) The method of claim 13, wherein the controller is coupled to corresponding controller nodes of third and fourth transistors and controls operation of the third and fourth transistors, and wherein the node voltage is a first node voltage, the method further comprising: comparing a difference across third transistor of the second reference voltage and a second node voltage to a corresponding one of third and fourth threshold voltages; comparing a difference across fourth transistor of the first reference voltage and the second node voltage to a corresponding one of third and fourth threshold voltages, detecting an open circuit or a short circuit in at least one of the third transistor and the fourth transistor based on at least one of the comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 16 A method of detecting an open circuit or a short circuit in a switched-mode DC-DC converter having a switching regulator regardless of current direction, the method comprising: controlling, using a controller coupled to corresponding control nodes of first and second transistors, operation of the first and second transistors; comparing a difference across the first transistor of a first reference voltage or an output voltage and a node voltage to a corresponding one of first and second threshold voltages and outputting a first comparison to a first input of the controller; comparing a difference across the second transistor of a second reference voltage and the node voltage to a corresponding one of first and second threshold voltages and outputting a second comparison to a first input of the controller; and detecting an open circuit or a short circuit in at least one of the first transistor and the second transistor based on at least one of the first and second comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 17 (depends on 16) The method of claim 16, further comprising: receiving an enable signal configured to be set to a first logic level after a predetermined time following application of a second logic level of a control signal to either the first transistor or the second transistor. ### Claim 18 (depends on 17) The method of claim 17, further comprising: adjusting the predetermined time. ### Claim 19 A circuit configured to detect an open circuit or a short circuit in a switched-mode DC-DC converter having a switching regulator regardless of a direction of a load current, the circuit comprising: a first means for comparing a difference across a first transistor of a first reference voltage or an output voltage and a node voltage to a corresponding one of first and second threshold voltages and outputting a first comparison to a first input of the controller; a second means for comparing a difference across a second transistor of a second reference voltage and the node voltage to a corresponding one of first and second threshold voltages and outputting a second comparison to a second input of the controller; and a controller coupled to corresponding control nodes of the first and second transistors to control operation of the first and second transistors, wherein the first output of the first voltage detector circuit is coupled to a first input of the controller, wherein the second output of the second voltage detector circuit is coupled to a second input of the controller, and wherein the controller is configured to detect an open circuit or a short circuit in at least one of the first transistor and the second transistor based on at least one of the first and second comparisons regardless of the direction of the load current in the DC-DC converter. ### Claim 20 (depends on 19) The circuit of claim 19, wherein the node voltage is a first node voltage, the circuit further comprising: a third means for comparing a difference across a third transistor of the second reference voltage and a second node voltage to a corresponding one of third and fourth threshold voltages and outputting a third comparison to a third input of the controller; a fourth means for comparing a difference across a fourth transistor of the output voltage and the second node voltage to a corresponding one of third and fourth threshold voltages and outputting a fourth comparison to a fourth input of the controller, wherein the controller is further configured to detect an open circuit or a short circuit in at least one of the third transistor and the fourth transistor based on at least one of the third and fourth comparisons regardless of the direction of the load current in the DC-DC converter.