# US 2017/0288657 A1 · Gate drive circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288657 A1 - Document ID: US20170288657A1 - Status: Published application - Kind: A1 - Application number: 15/474,223 - Filed: 2017-03-30 - Published: 2017-10-05 - Earliest claimed: 2016-03-30 - Assignees: Rohm Co., Ltd. - Applicants: Rohm Co., Ltd. - Inventors: Tatsuya YANAGI; Hirotaka OTAKE; Takashi SAWADA; Seiya KITAGAWA - Web page: https://patentgrep.com/patent/US20170288657A1 ## CPC - H03K 17/04: Modifications for accelerating switching - H03K 17/04123: {in field-effect transistor switches} - H10D 30/66: Vertical DMOS [VDMOS] FETs - H10D 84/144: {in antiparallel diode configurations} - H10D 62/8325: {Silicon carbide} - 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) - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract A gate drive circuit has a capacitor and a gate drive voltage source connected in series with a gate terminal of a voltage-driven switching device. The gate drive source voltage feeds, as a gate drive voltage, a voltage higher than the sum of the voltage applied to a gate-source parasitic capacitance of the switching device when the switching device is in a steady ON state and the voltage applied to, of any circuit component interposed between the gate drive voltage source and the gate terminal of the switching device, a circuit component other than the capacitor (such as an upper transistor forming the output stage of the driver). No other circuit component (such as a resistor connected in parallel with the capacitor) is essential but the capacitor as the sole circuit component to be directly connected to the gate terminal of the switching device. ## Claims ### Claim 1 A gate drive circuit, comprising: a first capacitor and a first gate drive voltage source connected in series with a gate terminal of a switching device of a voltage-driven type, wherein the first gate drive voltage source is configured to feed, as a first gate drive voltage, a voltage higher than a sum of a voltage applied to a gate-source (emitter) parasitic capacitance of the switching device when the switching device is in a steady ON state and a voltage applied to, of any circuit component interposed between the first gate drive voltage source and the gate terminal of the switching device, a circuit component other than the first capacitor. ### Claim 2 (depends on 1) The gate drive circuit of claim 1, wherein the first gate drive voltage has a voltage value higher than a rated gate-source (gate-emitter) DC voltage of the switching device but lower than a rated gate-source (gate-emitter) surge voltage of the switching device, and the voltage applied to the gate-source (emitter) parasitic capacitance of the switching device when the switching device is in the steady ON state is adjusted to be lower than the rated DC voltage. ### Claim 3 (depends on 1) The gate drive circuit of claim 1, further comprising: a first discharger connected in parallel with the first capacitor, the first discharger being configured to discharge the first capacitor when the switching device is OFF. ### Claim 4 (depends on 3) The gate drive circuit of claim 3, wherein the first discharger includes a first resistor, and the gate drive circuit further comprises a second resistor connected between a gate and a source (emitter) of the switching device. ### Claim 5 (depends on 4) The gate drive circuit of claim 4, wherein let a capacitance value of the first capacitor be Cg, let a capacitance value of the gate-source (emitter) parasitic capacitance observed when the switching device is in the steady ON state be Cgs, let a resistance value of the first resistor be Rg, and let a resistance value of the second resistor be Rgs, then a relationship of Cg:(Cg+Cgs)=(Rg//Rgs):Rg holds. ### Claim 6 (depends on 3) The gate drive circuit of claim 3, wherein the first discharger includes a switch. ### Claim 7 (depends on 3) The gate drive circuit of claim 3, further comprising: a second gate drive voltage source connected to a first gate drive voltage source side of the first discharger. ### Claim 8 (depends on 3) The gate drive circuit of claim 3, further comprising: a second discharger of which a first terminal is connected to the gate terminal of the switching device; and a second gate drive voltage source connected to a second terminal side of the second discharger. ### Claim 9 (depends on 8) The gate drive circuit of claim 8, wherein the second discharger includes a second capacitor. ### Claim 10 (depends on 8) The gate drive circuit of claim 8, wherein the second discharger includes a third resistor. ### Claim 11 A gate drive circuit, comprising: a capacitor and a gate drive voltage source connected in series with a gate terminal of a switching device of a voltage-driven type, wherein the capacitor is a sole circuit component directly connected to the gate terminal of the switching device.