Communications network of passenger protection system

• US 20100121534A1
• Filed: 11/10/2009
• Published: 05/13/2010
• Est. Priority Date: 11/12/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tanaka, Tatsuki
• Granted Patent: US 8,145,387 B2
• Time in Patent Office: Days
• US Class Current: 701/45
• CPC Class Codes: H04L 12/40039 Details regarding the setting of the power status of a node according to activity on the bus
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]

Abstract

A communications network for a passenger protection system of a vehicle has an electronic control unit and a plurality of sensors, which is bus-connected to the electronic control unit. Each of the sensors includes a current detection circuit for detecting a current of the sensor, and a control circuit including a memory. The control circuit sets a specific address for the sensor in the memory when the detected current attains a predetermined relation to a predetermined threshold current. The control circuit transmits a notification of completion of setting the specific address to the electronic control unit, and controls a mode of the sensor to a specific mode, which consumes current less than the predetermined threshold current.

Claims

1. A communications network for a passenger protection system of a vehicle including a passenger protection device, the communications network comprising:

an electronic control unit configured to control the passenger protection device upon collision of the vehicle; and

a plurality of sensors bus-connected to the electronic control unit and configured to detect and transmit a parameter related to the collision of the vehicle,

wherein each of the sensors includes

a current detection circuit configured to detect a current of the sensor, and

a control circuit including a memory, the control circuit being configured to set a specific address for the sensor in the memory when the current detected by the current detection circuit attains a predetermined relation to a predetermined threshold current, to transmit a notification of completion of setting the specific address to the electronic control unit, to control a mode of the sensor to a specific mode, which consumes current less than the predetermined threshold current,

whereby the plurality of sensors is set with respective addresses and transmit notifications of completion of setting respective addresses to the electronic control unit at time of initialization for communications with the electronic control unit.

2. The communications network according to claim 1, wherein:

the control circuit is configured to set and store the specific address, which is different from addresses of any other sensors among the plurality of sensor, and notify the other sensors of the specific address set for the sensor.

3. The communications network according to claim 1, wherein:

the electronic control unit includes a communications control circuit for transmitting the specific address to the sensor which is rendered operative to transmit and receive signals;

the control circuit is configured to render the sensor to a two-way communications condition, in which both signal transmission and signal reception are possible, from a one-way communications condition, in which only signal reception is possible, when the current detected by the current detection circuit attains the predetermined relation relative to the predetermined threshold current, to notify the electronic control unit of the two-way communications condition, and to receive the specific address to be stored in the memory from the electronic control unit after notification of the two-way communications condition.

4. The communications network according to claim 1, wherein:

the electronic control unit includes a communications control circuit configured to store a predetermined correspondence relation between the plurality of sensors and specific addresses, and to transmit a response indicating permission or prohibition of the specific address based on the predetermined correspondence relation in response to a request of permission of the specified address from the sensor; and

the control circuit is configured to set a provisional address when the current detected by the current detection circuit attains the predetermined relation relative to the predetermined threshold current, to transmit a request for permission of the provisional address to the electronic control unit, and to fix the provisional address as the specific address to be stored in the memory upon receiving the response of permission from the electronic control unit, the control unit repeating setting of a provisional address and transmission of a request for permission until the response of permission is received from the electronic control unit.

5. The communications network according to claim 1, wherein:

the predetermined threshold current is less than an operation current required for the sensor to operate in a normal communications mode.

6. The communications network according to claim 1, wherein:

the electronic control unit includes a communications control circuit configured to transmit a command of releasing the specific mode to all the plurality of sensors; and

the control circuit is configured to return the sensor from the specific mode to a normal operation mode upon receiving the command from the electronic control unit.

7. The communications network according to claim 1, wherein:

the current detection circuit is configured to detect one of an output current flowing out from an output side of the sensor and an input current flowing in at an input side of the sensor; and

the control circuit is configured to set the specific address only when the current detected by the current detection circuit is less and greater than the predetermined threshold current in case of detection of the output current and the input current, respectively.