Controller area network using transformers

• US 7,065,152 B2
• Filed: 10/28/2002
• Issued: 06/20/2006
• Est. Priority Date: 12/27/2001
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Gottshall, Paul, Armstrong, Mike
• Primary Examiner(s): Sircus, Brian
• Assistant Examiner(s): SQUIRES, BRETT S
• Application Number:
  US10/281,254
• Publication Number:
  US 20030123263A1
• Time in Patent Office: 1,331 Days
• Field of Search: 307/10.1, 375/285
• US Class Current: 375/285
• CPC Class Codes: H04L 12/40045 Details regarding the feeding of energy to the node from the bus
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle

Abstract

A controller area network (CAN) data link is provided including a first node, a second node, and a transformer circuit connected between the first and second nodes to provide electrical isolation. The transformer circuit provides the requisite electrical isolation and is reliable under high temperatures.

Claims

1. A controller area network (CAN) data link, comprising:

means for sending and receiving CAN messages;

controller means for controlling CAN messages; and

a circuit comprising;

a transformer for providing electrical isolation;

a first transistor coupled to a first R-C circuit and a second R-C circuit and coupled between the transformer and the controller means; and

a second transistor coupled between the transformer and the sending and receiving means.

2. The CAN data link of claim 1, wherein the first R-C circuit is coupled between the first transistor and the controller means and the second R-C circuit is coupled between the first transistor and the transformer.

3. A controller area network (CAN) data link, comprising:

means for sending and receiving CAN messages;

controller means for controlling CAN messages; and

a circuit comprising;

transformer means for providing electrical isolation;

a first transistor coupled to a first R-C circuit and a second R-C circuit and coupled between the transformer means and the controller means, wherein the first R-C circuit is coupled between the first transistor and the controller means and the second R-C circuit is coupled between the first transistor and the transformer means;

a second transistor coupled between the transformer means and the sending and receiving means; and

a diode coupled to the second R-C circuit and a voltage supply.

4. A controller area network (CAN) data link, comprising:

means for sending and receiving CAN messages;

controller means for controlling CAN messages; and

a circuit comprising;

transformer means for providing electrical isolation;

a first transistor coupled to a first R-C circuit and a second R-C circuit and coupled between the transformer means and the controller means, wherein the first R-C circuit is coupled between the first transistor and the controller means and the second R-C circuit is coupled between the first transistor and the transformer means; and

a second transistor coupled between the transformer means and the sending and receiving means,

wherein an emitter of the first transistor is coupled with a ground, an emitter of the second transistor is coupled with a ground, and a side of the transformer means is coupled with a ground.

5. A controller area network (CAN) data link, comprising:

a first node;

a second node; and

a transformer circuit coupled between the first and second nodes to provide electrical isolation, wherein the transformer circuit includes;

a first R-C circuit having a first and a second end, wherein the first end is coupled with the first node;

a first transistor, wherein the second end of the first R-C circuit is coupled with a first node of the first transistor and a second node of the first transistor is coupled with ground;

a second R-C circuit having a first and a second end, wherein the first end of the second R-C circuit is coupled with a third node of the first transistor;

a diode having a first and a second end, wherein the first end of the diode is coupled with the first end of the second R-C circuit and the second end of the diode is coupled with a voltage supply;

a transformer having a first side and a second side, wherein a first end of the first side is coupled with the second end of the diode, a second end of the first side is coupled with the second end of the second R-C circuit, and a first end of the second side is coupled with ground; and

a second transistor, wherein a first node of the second transistor is coupled with a second end of the second side of the transformer, a second node of the second transistor is coupled with ground, and a third node of the second transistor is coupled with the second node.

6. The CAN data link of claim 5, wherein the first node includes a CAN controller.

7. The CAN data link of claim 5, wherein the second node includes a transceiver.

8. The CAN data link of claim 7, wherein the second node further includes an isolated voltage supply.

9. A controller area network (CAN) data link, comprising:

a first node;

a second node; and

a transformer circuit coupled between the first and second nodes to provide electrical isolation, wherein the transformer circuit includes;

a first R-C circuit having a first and a second end, wherein the first end is coupled with the first node;

a first transistor, wherein the second end of the first R-C circuit is coupled with a base of the first transistor and an emitter of the first transistor is coupled with ground;

a second R-C circuit having a first and a second end, wherein the first end of the second R-C circuit is coupled with a collector of the first transistor;

a diode having a first and a second end, wherein the first end of the diode is coupled with the first end of the second R-C circuit and the second end of the diode is coupled with a voltage supply;

a transformer having a first side and a second side, wherein a first end of the first side is coupled with the second end of the diode, a second end of the first side is coupled with the second end of the second R-C circuit, and a first end of the second side is coupled with ground; and

a second transistor, wherein a base of the second transistor is coupled with a second end of the second side of the transformer, an emitter of the second transistor is coupled with ground, and a collector of the second transistor is coupled with the second node.

10. The CAN data link of claim 9, wherein the first node includes a CAN controller.

11. The CAN data link of claim 9, wherein the second node includes a transceiver.

12. The CAN data link of claim 11, wherein the second node further includes an isolated voltage supply.

13. A method for providing electrical isolation in a controller area network, the method comprising:

providing a first and a second node;

providing a transformer circuit;

connecting a first end of the transformer circuit to the first node; and

connecting a second end of the transformer circuit to the second node,

wherein the step of providing a transformer circuit includes;

providing a first R-C circuit having a first and a second end, wherein the first end is coupled with the first node;

providing a first transistor, wherein the second end of the first R-C circuit is coupled with a base of the first transistor and an emitter of the first transistor is coupled with ground;

providing a second R-C circuit having a first and a second end, wherein the first end of the second R-C circuit is coupled with a collector of the first transistor;

providing a diode having a first and a second end, wherein the first end of the diode is coupled with the first end of the second R-C circuit and the second end of the diode is coupled with a voltage supply;

providing a transformer having a first side and a second side, wherein a first end of the first side is coupled with the second end of the diode, a second end of the first side is coupled with the second end of the second R-C circuit, and a first end of the second side is coupled with ground; and

providing a second transistor, wherein a base of the second transistor is coupled with a second end of the second side of the transformer, a emitter of the second transistor is coupled with ground, and a collector of the second transistor is coupled with the second node.

14. The method of claim 13, wherein the step of providing a first and second node includes providing a CAN controller for handling incoming and outgoing CAN messages.

15. The method of claim 14, wherein the step of providing a first and second node further includes providing an isolated voltage supply.

16. The method of claim 13, wherein the step of providing a first and second node includes providing a transceiver.