Overcurrent protection device and vehicular electronic control unit

Patent metadata

Field	Value
Publication number	US-10615586-B2
Application number	US-201815888419-A
Country	US
Kind code	B2
Filing date	Feb 5, 2018
Priority date	Apr 6, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

There is provided an overcurrent protection device configured to protect a load from an overcurrent. A first overcurrent detector configured to detect the overcurrent, based on a value of a current flowing through the load, time for which the current flows through the load, and an overcurrent cutoff characteristic upon non-operation of the load. An overcurrent breaker that cuts off the overcurrent to the load when the first overcurrent detector detects the overcurrent.

First claim

What is claimed is:

1. An overcurrent protection device configured to protect a load from an overcurrent, the overcurrent protection device comprising:
a first overcurrent detector configured to detect the overcurrent, based on a value of a current flowing through the load, time for which the current flows through the load, and an overcurrent cutoff characteristic upon non-operation of the load, the overcurrent cutoff characteristic being a characteristic whereby a noise to be input to the load upon non-operation of the load and a rush current to temporarily flow upon connection of the load to a regular power supply are allowed, and the overcurrent upon non-operation to the load is cut off, and
an overcurrent breaker that cuts off the overcurrent to the load when the first overcurrent detector detects the overcurrent,
wherein the first overcurrent detector detects the overcurrent when time for which the value of the current flowing through the load upon operation of the load is larger than a first threshold value is greater than a second threshold value, and the first threshold value and the second threshold value are determined by the overcurrent cutoff characteristic upon the non-operation of the load.

2. The overcurrent protection device according to claim 1 , further comprising a second overcurrent detector configured to detect the overcurrent upon operation of the load, based on either the value of the current flowing through the load upon the operation of the load or a value of another current flowing through the load upon the operation of the load, time for which the current flows through the load upon the operation of the load, and an overcurrent cutoff characteristic upon the operation of the load,
wherein the overcurrent breaker cuts off the overcurrent to the load when the second overcurrent detector detects the overcurrent.

3. The overcurrent protection device according to claim 2 ,
wherein the second overcurrent detector detects the overcurrent when time for which the value of the current flowing through the load upon the operation of the load is larger than a third threshold value is greater than a fourth threshold value, the third threshold value and the fourth threshold value are determined by the overcurrent cutoff characteristic upon the operation of the load, the third threshold value is smaller than the first threshold value, and the fourth threshold value is smaller than the second threshold value.

4. The overcurrent protection device according to claim 2 , wherein the first overcurrent detector is configured to detect the overcurrent upon the non-operation of the load, and to stop the detection of the overcurrent upon the operation of the load.

5. The overcurrent protection device according to claim 2 , wherein the overcurrent cutoff characteristic upon the operation of the load is determined, depending on a surrounding temperature.

6. A vehicular electronic control unit comprising the overcurrent protection device according to claim 1 .

Assignees

• Denso Ten Ltd

Inventors

• Kozuki Yasunori
• Urashima Kosuke
• Shingo Nobuhiro
• Kato Takaaki

Classifications

• H02H3/093

  with timing means {(in general H02H3/027; thermal delay H02H3/085; timing means for undervoltage protection H02H3/247)} · CPC title

• H02H1/0007 Primary

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H02H7/20

  for electronic equipment (for converters H02H7/10; for electric measuring instruments G01R1/36; for DC voltage or current semiconductor regulators G05F1/569; for amplifiers H03F1/52; for electronic switching circuits H03K17/08) · CPC title

• H02H3/085

  making use of a thermal sensor, e.g. thermistor, heated by the excess current (also responsive to the temperature of the protected device H02H5/041, thermal images H02H6/00) · CPC title

• B60L3/04

  Cutting off the power supply under fault conditions (protective devices and circuit arrangements in general H01H; H02H) · CPC title