Slave Circuit Conflict Detection on Two-Wire Bus
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Solution Overview
Problem
I2C bus conflicts, particularly due to external short-circuits or noise, can lead to excessive current and damage to slave circuits, especially in 'fast-mode plus' operations, where lower impedance results in higher short-circuit currents.
Innovation Solution
A method and circuit configuration that detects conflicts by comparing line voltages with a reference, generates an internal signal mimicking a STOP condition to stop data transmission, and places the slave circuit in a standby listening state, preventing overheating and damage, while inhibiting potentially corrupted programming operations in EEPROMs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the slave circuit imposes priority logic level on the bus line, then data transmission is enabled, but conflict may occur when externally forced to other logic level causing excessive current
Solution Approach 1:
The patent applies preliminary anti-action by implementing a conflict detection mechanism that anticipates potential conflicts before they cause damage. The slave circuit continuously monitors the bus line voltage and detects when an external force attempts to force the line to a different logic level, preventing the excessive current condition from fully developing by triggering a protective response.
Solution Approach 2:
The patent converts the harmful conflict condition into a beneficial protective mechanism. When a conflict is detected (external forcing of the bus line), the circuit uses this harmful condition as a trigger to activate protection mode, stopping data transmission and preventing damage. The harmful external interference becomes the signal that activates the safeguard.
2Reliability
If conflict detection and protection mechanisms are implemented, then circuit reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by implementing a conflict detection mechanism that uses the slave circuit's own existing monitoring capabilities. The circuit detects conflicts on the bus line it is already connected to and autonomously triggers the protection response without requiring external intervention or complex additional control systems.
Solution Approach 2:
The patent merges the conflict detection function with the existing data transmission monitoring circuitry. The same monitoring mechanisms that track data line status for communication purposes are also used to detect voltage anomalies indicating conflicts, eliminating the need for completely separate detection circuits and reducing overall complexity.
Data Source
AI summary
A method is provided for managing the operation of a circuit operating in a slave mode. The circuit is connected to a bus having at least two of wires and a priority logic level. The slave circuit imposes the priority logic level on a first wire of the bus. While imposing, the slave circuit detects a possible conflict on the first wire resulting from a forcing, external to the slave circuit, of the first wire to another logic level. Upon detecting a conflict, the slave circuit is placed in a state stopping the sending by the circuit of any data over the bus while leaving the circuit listening to the bus.