Method and device for the protection of a series bus against short circuits
AssigneeSGS-Thomson Microelectronics S.A.
InventorMaurice G. Le Van Suu
Life of this patent
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Abstract
The disclosure relates to the methods and devices that enable series type buses to be protected against the consequences of a short-circuit in the decentralized units connected to this bus. There are provided means to detect the equalization of the potentials of the data wires and means enabling the disconnection, under the control of these detection means, of the decentralized unit responsible for the short circuit. A device is also provided to short circuit the supply wires of the bus according to a predetermined sequence in order to inform the central processing unit of the disconnection of said decentralized unit. The disclosure enables the protection of the central processing unit and of the decentralized units, connected to the bus, that are not malfunctioning.
Claims30
A method for the protection of a series bus against short circuits, comprising the steps of:
- detecting a short circuit condition, between at least two data wires within the series bus, wherein the series bus interconnects a centralized processing unit and at least one decentralized processing unit;
- and
- disconnecting, responsive to the step of detecting, a decentralized unit containing the short circuit condition.
A method for protecting a bus against a short circuit, comprising, by a decentralized device on the bus, the steps of:
- monitoring a pair of data conductors conveyed by the bus to determine whether a short circuit has occurred between the pair of data conductors;
- disconnecting, responsive to a detection of a short circuit, at least one of the data conductors of the pair of data conductors;
- determining whether the short circuit disappears after the step of disconnecting;
- and
- reconnecting the at least one data conductor, responsive to a determination by the step of determining that the short circuit disappears.
The method of claim 11, wherein the step of disconnecting further comprises:
- storing, responsive to the third binary signal indicating that a short circuit persists, a value in a memory device to generate a fourth binary signal;
- and
- opening a switch, responsive to the fourth binary signal, to isolate the at least one data conductor from the decentralized device.
In a system having a plurality of decentralized devices connected together by a bus, an apparatus for protecting the bus against short circuits, comprising, within at least one decentralized device:
- means for detecting a short circuit between a pair of data conductors conveyed by the bus;
- means for disconnecting the pair of data conductors from the decentralized device;
- means for determining whether the short circuit disappears after the pair of data conductors are disconnected;
- and
- means for reconnecting the pair of data conductors, responsive to the means for determining indicating that the short circuit disappeared.
In a system having a plurality of decentralized devices connected together by a bus, an apparatus for protecting the bus against short circuits, comprising, within a decentralized device:
- a detector coupled to a pair of data conductors within the bus that generates a first binary signal indicative of whether there is a short circuit between the pair of data conductors;
- a memory device, having a setting input, a resetting input, and an output, the setting input being coupled to the first binary signal, the memory device generating a second binary signal at the output responsive to a state of the first binary signal;
- a first switch, coupling the pair of data conductors to the decentralized device, that alternately opens and closes responsive to the second binary signal;
- a first delay circuit that delays the second binary signal and generates a third binary signal;
- and
- a logic circuit, receiving the first binary signal and the third binary signal, that generates a fourth binary signal, the fourth binary signal coupling to the resetting input of the memory device.
Dependencies are inferred from the claim text.