Fault current recognition in control units

• US 6,489,778 B2
• Filed: 10/28/1999
• Issued: 12/03/2002
• Est. Priority Date: 10/30/1998
• Status: Expired due to Fees

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Mannesmann VDO AG (Continental AG)
• Inventors: Martin, Edmund
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Hamdan, Wasseem H.
• Application Number:
  US09/429,546
• Publication Number:
  US 20010030542A1
• Time in Patent Office: 1,132 Days
• Field of Search: 324/500, 324/511, 324/522, 324/537, 324/133, 361/78, 361/79, 361/82, 361/84, 361/87
• US Class Current: 324/500
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches

Abstract

A method of reconizing a fault current in a control unit and to a control unit having a circuit for recognizing the fault current. According to the invention, a current flowing into the control unit which could cause the control unit to be damaged or to operate incorrectly is detected and a fault signal is produced depending on the current detected, the fault signal causing the load or the current supply for the control unit to be switched off, for example.

Claims

1. A method of recognizing a fault current in a control unit having an output connected to a load which can be switched by a switch such that the load is enabled or disabled, wherein the switch is located in the control unit along a path of current flow through the control unit and into the load, the method including steps of controlling the switch by the control unit, detecting within the control unit a current flowing into the control unit via the control unit'"'"'s output, producing a fault signal depending on the fault current detected in the control unit, and wherein the detecting step is accomplished by use of a transistor circuit located within the control unit and comprising a transistor and a voltage divider establishing a voltage at a terminal of the transistor, the switch comprises a driver, the voltage divider is connected between terminals of the driver, and a further terminal of the transistor produces the fault signal and is available for use via a processor for control of the driver.

2. The method as claimed in claim 1, wherein the load is switched off when the fault signal is produced.

3. The method as claimed in claim 2, further comprising the step of switching off a current supply for the control unit when the fault signal is produced.

4. The method as claimed in claim 1, wherein the current flowing into the control unit is switched off when the fault signal is produced.

5. The method as claimed in claim 1, wherein the current flowing into the control unit is supplied to the transistor via the voltage divider, the fault signal being produced by the transistor after it has been switched on.

6. A control unit (1) having a circuit for recognizing a fault current (FI) in the control unit (1), the control unit having an output (4) connected to a load (5) which can be switched by a switch such that the load is an enabled or disabled, wherein the switch is located in the control unit along a path of current flow through the control unit and into the load and is controlled by the control unit (1), wherein the fault current (FI) flowing into the control unit (1) via the control unit'"'"'s (1) output (4) is supplied to the circuit and is detected by the circuit, and a fault signal is produced by the circuit depending on the fault current (FI) detected in the control unit (1), and wherein detection of the fault current is accomplished by use of a transistor circuit located within the control unit and comprising a transistor and a voltage divider establishing a voltage at a terminal of the transistor, the switch comprises a driver, the voltage divider is connected between terminals of the driver, and a further terminal of the transistor produces the fault signal and is available for use via a processor for control of the driver.

7. The control unit (1) as claimed in claim 6, wherein the circuit is arranged physically close to the driver (6) of the control unit (1).

8. A method of recognizing a fault current in a control unit having an output connected to a load the load being switchable by a switch such that the load is enabled or disabled, wherein the switch is located in the control unit along a path of current flow through the control unit and into the load, the method comprising the steps of:

controlling the switch by the control unit,

detecting within the control unit a current flowing into the control unit via the control unit'"'"'s output,

producing a fault signal dependent on the detected current in the control unit, and

wherein the detecting step is accomplished by use of a transistor circuit located within the control unit and comprising a transistor and a voltage divider establishing a voltage at a terminal of the transistor, the switch comprises a driver, the voltage divider is connected between terminals of the driver, and a further terminal of the transistor produces the fault signal and is available for use via a processor for control of the driver.