Open-Drain Bus Repeater With Rise-Time Acceleration and Pull-Down Detection
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Solution Overview
Problem
Existing bus repeaters for open-drain bus communication, particularly in I2C bus systems, face challenges in efficiently detecting external pull-down events and maintaining reliable communication due to constraints on system implementation and detection complexity.
Innovation Solution
The proposed bus repeater incorporates a repeating unit with a B-side accelerator element and a control unit that controls the accelerator to pull up the voltage at the B-side terminal during a rising edge, and a pull-down detection unit to detect external pull-down events, thereby improving communication efficiency and detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional bus repeater is used without an accelerator element, then the device complexity is lower, but the rise time for bus line voltages is excessive and communication efficiency deteriorates
Solution Approach 1:
The accelerator element is activated in advance during the rising edge of the voltage to preemptively charge the bus line capacitance, reducing the rise time before the voltage transition is complete. This preliminary action allows the system to achieve faster voltage transitions without requiring a complete redesign of the bus architecture.
Solution Approach 2:
The accelerator element dynamically changes the effective resistance parameter of the pull-up path by providing an additional current path. This parameter change allows the system to achieve faster charging of the bus line capacitance, directly reducing the rise time without permanently increasing the static power consumption.
2Speed
If the accelerator element is activated continuously, then the rise time is reduced, but the power consumption increases
Solution Approach 1:
The accelerator element is activated periodically only during the rising edge of the voltage transition rather than continuously. This periodic activation is synchronized with the communication protocol, allowing the system to achieve fast rise times when needed while minimizing power consumption during idle or falling edge periods.
Solution Approach 2:
The activation state of the accelerator element is dynamically changed based on the voltage transition state. The element is enabled during rising edges and disabled otherwise, creating a dynamic power management scheme that adapts to the instantaneous communication needs of the system.
3Measurement precision
If detection circuitry is added to detect external pull-down events, then the measurement precision improves, but the device complexity and detection difficulty increase
Solution Approach 1:
The accelerator element serves multiple functions: it accelerates voltage rising edges and simultaneously acts as a detection mechanism for external pull-down events. By monitoring the voltage transition characteristics at the same node used for acceleration, the system achieves pull-down detection without adding separate detection circuitry.
Solution Approach 2:
The detection function is merged with the acceleration function by using the same hardware component (accelerator element) and the same voltage node for both purposes. This merging eliminates the need for separate detection circuitry and reduces the overall device complexity while maintaining detection precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution reduces the rise time for bus line voltages, enhances the detection of external pull-down events, and improves the overall reliability and efficiency of open-drain bus communication systems, while minimizing power consumption.
Implementation Method 1
First bus line 102a and second bus line 103a each have a parasitic capacitance associated therewith, denoted by C1 and C2, respectively
Implementation Method 2
a current through pull-up resistor R1 charges capacitance C1 until the voltage on first bus line 102a is pulled up to supply voltage Vcc
Data Source
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AI summary
The present invention generally relates to a repeater for open-drain bus communication and a system comprising the same. More particularly, the present invention relates to a repeater that is suitable for I2C bus communication. A bus repeater (1) for open-drain bus communication is provided. The repeater (1) comprises at least one repeating unit, the repeating unit having an A-side terminal (2a) configured to be electrically connected to an A-side open-drain bus, and a B-side terminal (2b) configured to be electrically connected to a B-side open-drain bus. The repeater is operable in a first mode in which the repeating unit is configured to receive a signal at the A-side terminal (2a) and to produce a signal at the B-side terminal (2b) based on the signal received at the A-side terminal. The repeating unit comprises a B-side accelerator element (3b) electrically connected to the B-side terminal. Further, the repeating unit further comprises a first control unit (11a) configured to, when the repeating unit is operating in the first mode, control the B-side accelerator element (3b) to pull up a voltage at the B-side terminal (2b) when the voltage at the A-side terminal (2a) surpasses a first threshold voltage during a rising edge of said voltage, and to subsequently control the B-side accelerator element to stop pulling up the voltage at the B-side terminal when the voltage at the B-side terminal surpasses a second threshold voltage.