# US 2018/0323601 A1 · Current cut-off device, and wire harness

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- Number: US 2018/0323601 A1
- Document ID: US20180323601A1
- Status: Published application
- Kind: A1
- Application number: 16/038,477
- Filed: 2018-07-18
- Published: 2018-11-08
- Earliest claimed: 2016-02-04
- Assignees: Yazaki Corporation
- Applicants: Yazaki Corporation
- Inventors: Koki SATO; Koichi UEZONO; Naoya KOJIMA; Hiromichi INOUE
- Web page: https://patentgrep.com/patent/US20180323601A1

## CPC

- H02H 3/087: for DC applications
- B60R 16/02: electric {constitutive elements}
- B60R 16/03: for supply of electrical power to vehicle subsystems {or for (circuit arrangements for charging batteries H02J7/00)}
- H01H 89/00: Combinations of two or more different basic types of electric switches, relays, selectors and emergency protective devices, not covered by any single one of the other main groups of this subclass
- H02H 9/02: responsive to excess current {(current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025)}
- H02H 9/025: {Current limitation using field effect transistors}
- H01H 9/106: {fuse and switch being connected in parallel}
- H01H 9/541: {Contacts shunted by semiconductor devices}
- 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)
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00)

## Abstract

A current cut-off device includes a first current cut-off circuit and a second current cut-off circuit. The first current cut-off circuit is physically cut off in response to a current having a predetermined value or more. The second current cut-off circuit includes at least one semiconductor switching device and is cut off in response to a current having a predetermined value or more. The first current cut-off circuit and the second current cut-off circuit are connected in parallel to each other. A ratio of a current flowing through the first current cut-off circuit to a current flowing through the second current cut-off circuit is set within a prescribed value set in advance, under predetermined conditions.

## Claims

### Claim 1

A current cut-off device comprising:
a first current cut-off circuit that is physically cut off in response to a current having a predetermined value or more; and
a second current cut-off circuit that includes at least one semiconductor switching device and is cut off in response to a current having a predetermined value or more,
wherein the first current cut-off circuit and the second current cut-off circuit are connected in parallel to each other, and
wherein a ratio of a current flowing through the first current cut-off circuit to a current flowing through the second current cut-off circuit is set within a prescribed value set in advance, under predetermined conditions.

### Claim 2 (depends on 1)

The current cut-off device according to claim 1, wherein the first current cut-off circuit is a fusible link used for a wire harness installed on a vehicle.

### Claim 3 (depends on 1)

The current cut-off device according to claim 1, wherein an electric resistance value of the second current cut-off circuit is set based on an electric resistance value of the first current cut-off circuit and the ratio.

### Claim 4 (depends on 3)

The current cut-off device according to claim 3, wherein the second current cut-off circuit is configured by a parallel switch circuit in which a plurality of sets of semiconductor switching devices are connected in parallel to each other.

### Claim 5 (depends on 1)

A wire harness comprising:
the current cut-off device according to claim 1;
a first electric wire that connects a generator installed in a vehicle and the current cut-off device to each other, and
a second electric wire that connects the current cut-off device and a load or a battery installed in the vehicle to each other,
a sectional area of a conductor of the first electric wire and a sectional area of a conductor of the second electric wire are set according to a rated cut-off current of the first current cut-off circuit.