I3C Pull-Up Current Control in FPGA Communication Interfaces

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Solution Overview

Problem

Current I3C implementations for FPGAs require external pull-up logic, increasing cost and board area due to the need for additional input/output circuitry to dynamically switch the built-in weak pull-up resistor, which is only configurable during FPGA initialization.

Innovation Solution

An integrated circuit with a communication controller circuit, a current controller circuit, and an input/output circuit that includes a transistor and a resistor, allowing the current controller circuit to dynamically turn on or off the pull-up current through the resistor and transistor in response to commands from the communication controller circuit, eliminating the need for external components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If external pull-up logic is used to dynamically switch the pull-up resistor, then I3C communication functionality is achieved, but circuit board area and IO resources increase

Engineering Contradiction:

ImproveI3C communication functionalityVSAvoidcircuit board area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent merges the pull-up resistor and transistor directly into the FPGA fabric, combining previously separate external components with internal logic. This integration eliminates the need for external pull-up logic while maintaining I3C communication functionality, thereby reducing circuit board area and IO resource usage.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If external pull-up logic is used to dynamically switch the pull-up resistor, then I3C communication functionality is achieved, but device complexity and cost increase

Engineering Contradiction:

ImproveI3C communication functionalityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the pull-up resistor, transistor, and switching logic into a single integrated unit within the FPGA. This merging reduces device complexity by eliminating separate external components and simplifying the overall system architecture while preserving full I3C communication capability.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of manufacture

If the built-in weak pull-up resistor is only configurable during initialization, then internal resource usage is optimized, but dynamic pull-up control during operation is lost

Engineering Contradiction:

Improveinternal resource optimizationVSAvoiddynamic pull-up control

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The patent implements dynamic control of the pull-up resistor during FPGA operation by introducing a controllable transistor that can be switched on and off based on operational requirements. This dynamic mechanism allows the pull-up function to be activated only when needed, optimizing internal resource usage while maintaining operational flexibility.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent prepares the pull-up control mechanism during initialization by setting up the transistor and control logic, enabling rapid activation or deactivation during operation without requiring full reconfiguration. This preliminary setup allows the system to switch between I2C and I3C modes efficiently during runtime.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250104745A1Current Control Systems And Methods For Communications Between Devices

Publication Date: 2025.03.27 ALTERA CORP

AI summary

An integrated circuit includes a communication controller circuit for exchanging communications with a device external to the integrated circuit through a signal line, a current circuit coupled to the signal line, and a current controller circuit for causing the current circuit to provide a constant current to the signal line while a signal is transmitted through the signal line based on a command generated by the communication controller circuit.