# US 12,191,846 B2 · Determination device and switch system equipped therewith > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,191,846 B2 - Document ID: US12191846B2 - Status: Granted - Kind: B2 - Application number: 17/904,384 - Filed: 2021-02-16 - Published: 2023-03-16 - Granted: 2025-01-07 - Earliest claimed: 2020-03-30 - Assignees: Panasonic Intellectual Property Management Co., Ltd. - Applicants: Panasonic Intellectual Property Management Co., Ltd. - Inventors: Yusuke Kinoshita; Hidetoshi Ishida - Web page: https://patentgrep.com/patent/US12191846B2 ## CPC - H03K 17/0822: {in field-effect transistor switches} - H02M 1/00: Details of apparatus for conversion - H03K 17/08122: {in field-effect transistor switches} - H03K 17/6871: {the output circuit comprising more than one controlled field-effect transistor} - H03K 2017/6878: {using multi-gate field-effect transistors} - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - 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 Provided are a determination device and a switch system capable of suppressing a power loss of a semiconductor switch. Determination device is used for semiconductor switch. Semiconductor switch includes junction field-effect transistor having gate and source corresponding to gate. Determination device includes resistor and determination circuit. Resistor has a first end and a second end. The first end of resistor is connected to gate. Determination circuit determines that overcurrent is flowing through semiconductor switch when there is a predetermined change in gate-source voltage of junction field-effect transistor in a range smaller than gate drive voltage provided between the second end of resistor and source. ## Claims ### Claim 1 A determination device used for a semiconductor switch including a junction field-effect transistor having a gate and a source corresponding to the gate, the device comprising: a resistor that has a first end and a second end, the first end being connected to the gate; and a determination circuit that determines that an overcurrent is flowing through the semiconductor switch when there is a predetermined change in a gate-source voltage of the junction field-effect transistor in a range smaller than a gate drive voltage given between the second end of the resistor and the source, wherein the semiconductor switch is a bidirectional switch including two junction field-effect transistors, the two junction field-effect transistors include a first junction field-effect transistor and a second junction field-effect transistor, the determination device includes two resistors, and two determination circuits, the two resistors include a first resistor corresponding to the first junction field-effect transistor and a second resistor corresponding to the second junction field-effect transistor, and the two determination circuits include a first determination circuit corresponding to the first junction field-effect transistor and a second determination circuit corresponding to the second junction field-effect transistor. ### Claim 2 (depends on 1) The determination device according to claim 1, wherein the predetermined change includes a change determined by a threshold. ### Claim 3 (depends on 1) The determination device according to claim 1, wherein the predetermined change includes a change determined by an amount of change. ### Claim 4 (depends on 1) The determination device according to claim 1, wherein the first determination circuit compares the gate-source voltage of the first junction field-effect transistor with a first threshold, and the second determination circuit compares the gate-source voltage of the second junction field-effect transistor with a second threshold. ### Claim 5 (depends on 1) The determination device according to claim 1, wherein the first determination circuit compares the gate-source voltage of the first junction field-effect transistor with a moving average value of a gate voltage when the first junction field-effect transistor is turned on, and the second determination circuit compares the gate-source voltage of the second junction field-effect transistor with a moving average value of a gate voltage when the second junction field-effect transistor is turned on. ### Claim 6 (depends on 1) The determination device according to claim 1, further comprising a third determination circuit that determines whether or not there is an anomaly of the semiconductor switch based on a determination result of the first determination circuit and a determination result of the second determination circuit. ### Claim 7 (depends on 6) The determination device according to claim 6, wherein the third determination circuit determines a direction in which the overcurrent is flowing. ### Claim 8 (depends on 7) The determination device according to claim 7, further comprising a control circuit that controls the first junction field-effect transistor and the second junction field-effect transistor based on a determination result of the third determination circuit, wherein the control circuit first turns off the first junction field-effect transistor out of the first junction field-effect transistor and the second junction field-effect transistor when the gate-source voltage of the first junction field-effect transistor is higher than a first reference voltage and the gate-source voltage of the second junction field-effect transistor decreases from a second reference voltage, and first turns off the second junction field-effect transistor out of the first junction field-effect transistor and the second junction field-effect transistor when the gate-source voltage of the first junction field-effect transistor is lower than the first reference voltage and the gate-source voltage of the second junction field-effect transistor increases from the second reference voltage. ### Claim 9 A determination device used for a semiconductor switch including a junction field-effect transistor having a gate and a source corresponding to the gate, the device comprising: a resistor that has a first end and a second end, the first end being connected to the gate; and a determination circuit that determines that an overcurrent is flowing through the semiconductor switch when there is a predetermined change in a gate-source voltage of the junction field-effect transistor in a range smaller than a gate drive voltage given between the second end of the resistor and the source, wherein the semiconductor switch is a dual-gate type junction field-effect transistor having two gates and two sources, the two gates include a first gate and a second gate, the two sources include a first source corresponding to the first gate and a second source corresponding to the second gate, the determination device includes two resistors, and includes two determination circuits, the two resistors include a first resistor connected to the first gate, and a second resistor connected to the second gate, the two determination circuits include a first determination circuit corresponding to the first gate and the first source, and a second determination circuit corresponding to the second gate and the second source, and the determination device further includes a third determination circuit that determines whether or not there is an anomaly of the semiconductor switch based on a determination result of the first determination circuit and a determination result of the second determination circuit. ### Claim 10 (depends on 6) The determination device according to claim 6, wherein in the semiconductor switch, the gate and the source of the first junction field-effect transistor are a first gate and a first source, respectively, the gate and the source of the second junction field-effect transistor are a second gate and a second source, respectively, and the first source of the first junction field-effect transistor and the second source of the second junction field-effect transistor are connected, the determination device further includes a control circuit that controls the first junction field-effect transistor and the second junction field-effect transistor based on a determination result of the third determination circuit, and the third determination circuit determines that the semiconductor switch is abnormal when a voltage between the second gate and the second source is higher than a first reference voltage and a voltage between the first gate and the first source decreases. ### Claim 11 (depends on 4) The determination device according to claim 4, wherein, in the semiconductor switch, the gate and the source of the first junction field-effect transistor are a first gate and a first source, respectively, the gate and the source of the second junction field-effect transistor are a second gate and a second source, respectively, the first source of the first junction field-effect transistor and the second source of the second junction field-effect transistor are connected, and the first threshold and the second threshold are same. ### Claim 12 (depends on 1) A switch system comprising: the determination device according to claim 1; and the semiconductor switch. ### Claim 13 (depends on 9) A switch system comprising: the determination device according to claim 9; and the semiconductor switch.