IC Pin Impedance Sensing for Low-Pin Digital Configuration

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Solution Overview

Problem

Conventional integrated circuit (IC) configuration schemes are costly and complex, occupying large circuit areas and requiring numerous pins for configuration, which is prohibitive for certain applications.

Innovation Solution

An integrated circuit with an impedance sensing circuit that determines the impedance of an external passive network connected to a pin, allowing the IC to be digitally configured into one of several states, reducing overhead and cost by using fewer pins and simplifying configuration processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional IC configuration schemes are used, then configuration capability is provided, but circuit area overhead and complexity increase

Engineering Contradiction:

Improveconfiguration capabilityVSAvoidcircuit area overhead

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical/configuration circuits with an impedance sensing circuit that uses electrical measurements to determine configuration states. The sensing circuit measures impedance values at configuration pins to identify external passive network configurations, thereby determining IC operational modes without requiring complex dedicated configuration circuitry.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the configuration approach from direct digital control to indirect impedance-based detection. By measuring electrical parameters (impedance) at the pins, the IC can infer configuration states based on the impedance characteristics of externally connected passive networks, reducing internal configuration complexity.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If conventional IC configuration schemes are used, then configuration capability is provided, but the number of pins required increases

Engineering Contradiction:

Improveconfiguration capabilityVSAvoidnumber of pins

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The configuration pins serve dual purposes: they are used for both normal IC operation and for impedance sensing during configuration detection. The same pins that would otherwise be dedicated solely to configuration functions can now participate in both operational modes, reducing the total pin count required.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the configuration detection function with the existing pin structure. Instead of adding separate dedicated configuration pins, the impedance sensing circuit utilizes the existing pin infrastructure, combining multiple functions into the same physical components.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If sequential programming is used for IC configuration, then configuration data can be loaded, but overhead and programming time increase

Engineering Contradiction:

Improveconfiguration flexibilityVSAvoidprogramming time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The external passive network configuration is established before the IC is powered on or before operation begins. The impedance sensing circuit detects this pre-established configuration immediately upon activation, eliminating the need for time-consuming sequential programming operations during IC operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The IC performs self-configuration by automatically detecting the impedance of externally connected passive networks through its impedance sensing circuit. This eliminates the need for external programming devices or sequential programming sequences, allowing the IC to configure itself upon power-up.

Inventive Principle:

Principle #25Self-service

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 impedance sensing circuit enables efficient digital configuration of ICs with reduced overhead and cost, allowing for more flexible and cost-effective use in various applications by utilizing external passive networks to determine configuration states.

Implementation Method 1

The impedance sensing circuit is configured to determine an impedance of a first external passive network when the first external passive network is electrically connected to the first pin

Methodology Applied

Scientific EffectImpedance sensing: Electrical Resistance

Data Source

PatentUS8957700B2Apparatus and methods for digital configuration of integrated circuits

Publication Date: 2015.02.17 ANALOG DEVICES INC

AI summary

Apparatus and method for digital configuration of integrated circuits (ICs) are provided herein. In certain implementations, an IC includes an impedance sensing circuit and at least one pin used for digital configuration. The impedance sensing circuit can detect an impedance value of an external passive network electrically connected to the pin, and can digitally configure the IC based on the detected impedance. For example, an end-user can connect an external resistor of a particular resistance to the pin, and the impedance sensing circuit can sense or detect the external resistor's resistance and digitally configure the IC based on the detected resistance. Accordingly, an end-user can digitally configure the IC by connecting a passive external component corresponding to a desired digital configuration to the pin. In certain implementations, the IC includes multiple pins, and the digital configuration is based on the impedances detected on each of the pins.