# US 2014/0192445 A1 · Electrostatic discharge protection circuit and semiconductor circuit device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0192445 A1 - Document ID: US20140192445A1 - Status: Published application - Kind: A1 - Application number: 14/134,239 - Filed: 2013-12-19 - Published: 2014-07-10 - Earliest claimed: 2013-01-07 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Masuhide IKEDA - Web page: https://patentgrep.com/patent/US20140192445A1 ## CPC - H02H 9/046: {responsive to excess voltage appearing at terminals of integrated circuits} - 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) ## Abstract The invention provides an electrostatic protection circuit that is effective in absorbing static electricity that is continuously input. The electrostatic protection circuit includes a circuit constituting a latch and a static electricity absorption circuit. When static electricity is input, the static electricity absorption circuit maintains its on state for a while at an output held by the latch circuit, and absorbs static electricity that is continuously input. When the static electricity has been absorbed, the output of the latch is inverted so as to turn off the static electricity absorption circuit, and the operation of absorbing static electricity ends. At this point in time, normal operation serving as an input terminal is performed. ## Claims ### Claim 1 An electrostatic discharge protection circuit comprising: a first line having a first potential; a second line having a second potential that is different from the first potential; a trigger circuit connected between the first line and the second line; and a discharge circuit including a field effect transistor that is connected between the first line and the second line, whose gate is directly or indirectly connected to a predetermined connection node of the trigger circuit, and that conducts electricity by a change in a potential of the gate, wherein the trigger circuit includes a first circuit and a second circuit that are connected in parallel, the first circuit includes: a first impedance element on the first line side and a capacitor element on the second line side that are connected in series between the first line and the second line; and a first transistor of first conductivity type that is connected in series to the first impedance element and is connected in parallel to the capacitor element, the second circuit includes: a first transistor of second conductivity type on the first line side and a second impedance element on the second line side that are connected in series between the first line and the second line, a gate of the first transistor of second conductivity type is connected to a first node located between the first impedance element and the, capacitor element, a gate of the first transistor of first conductivity type is connected to a second node located between the first transistor of second conductivity type and the second impedance element, and the predetermined connection node is the first node or the second node. ### Claim 2 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein the discharge circuit includes a second transistor of first conductivity type as the field effect transistor, and the second transistor of first conductivity type conducts electricity by an increase in a potential of the first node or the second node. ### Claim 3 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein the first impedance element is constituted by a resistive element. ### Claim 4 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein the second impedance element is constituted by a resistive element. ### Claim 5 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein the first impedance element is constituted by a second transistor of second conductivity type whose gate is connected to the second line. ### Claim 6 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein the second impedance element is constituted by a third transistor of first conductivity type whose gate is connected to the first line. ### Claim 7 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein the capacitor element is constituted by a fourth transistor of first conductivity type whose gate is connected to the first node. ### Claim 8 (depends on 1) The electrostatic discharge protection circuit according to claim 1, further comprising an inverter circuit whose input side is connected to the first node and whose output side is connected to the gate of the field effect transistor in the discharge circuit. ### Claim 9 (depends on 1) The electrostatic discharge protection circuit according to claim 1, wherein an impedance value of the first impedance element and a capacitance value of the capacitor element satisfy a predetermined condition that is set based on a relationship between the impedance value and the capacitance value that are set based on a power supply rise time during normal operation. ### Claim 10 (depends on 1) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 1. ### Claim 11 (depends on 2) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 2. ### Claim 12 (depends on 3) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 3. ### Claim 13 (depends on 4) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 4. ### Claim 14 (depends on 5) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 5. ### Claim 15 (depends on 6) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 6. ### Claim 16 (depends on 7) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 7. ### Claim 17 (depends on 8) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 8. ### Claim 18 (depends on 9) A semiconductor circuit device comprising the electrostatic discharge protection circuit according to claim 9.