IC Input Structures with Master-Slave Leakage Shut-Off

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Integrated circuits in mobile devices experience significant leakage currents at inputs, especially when disabled, due to the mismatch between low input signal voltages and higher power supply voltages, leading to unnecessary battery power consumption and non-deterministic switching-induced currents.

Innovation Solution

A master/slave input circuit arrangement is implemented, where the slave inputs are controlled by an enable input to break leakage current paths, and a hysteresis feedback circuit is coupled to improve input structure performance by adding a follow-on inverter and feedback loop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the IC is disabled to save power, then battery power consumption is reduced, but leakage currents at the inputs still occur

Engineering Contradiction:

Improvebattery power consumptionVSAvoidleakage currents at inputs

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The input circuit is divided into master inputs and slave inputs. The master input controls the enable state of the IC, while slave inputs are individually controlled by the master to shut off leakage paths. This segmentation allows selective control of different input paths based on the enable state.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The master input circuit performs preliminary action by controlling the enable state before the slave inputs can generate leakage currents. When the master input deactivates the IC, it proactively shuts off the leakage paths at slave inputs before they can contribute to power consumption.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a regulator is used to match input voltage levels, then switching reliability is improved, but circuit area and standby power increase

Engineering Contradiction:

Improveswitching reliabilityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The regulator circuit is completely removed from the design. Instead, the invention uses direct voltage level matching through the master-slave input structure, where the master input voltage directly controls the slave inputs without requiring an intermediate regulation stage.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The master input serves multiple functions: it controls the enable state of the IC, regulates the voltage levels for slave inputs, and shuts off leakage paths. This multi-functionality eliminates the need for separate regulator circuits while maintaining switching reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If the master input voltage is used directly to control slave inputs, then circuit complexity is reduced, but voltage level mismatch causes unreliable switching

Engineering Contradiction:

Improvecircuit complexityVSAvoidswitching reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The slave input circuits act as intermediaries between the master input and the internal IC circuitry. They receive the master input voltage and condition it appropriately to control the switching of internal circuits, ensuring reliable operation despite voltage level differences.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The slave input circuits change the voltage parameters from the master input level to appropriate levels for controlling internal switches. This parameter transformation ensures reliable switching without requiring complex voltage regulation circuits.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If slave inputs remain active during disabled state, then input responsiveness is maintained, but leakage current paths persist

Engineering Contradiction:

Improveinput responsivenessVSAvoidleakage current

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The slave inputs dynamically change their state based on the master input enable signal. When enabled, they are active and responsive; when disabled, they automatically shut off leakage paths. This dynamic behavior allows the system to adapt its responsiveness and power consumption based on operational requirements.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7539467B1Low leakage IC input structures including slaved standby current shut-off and increased gain for tighter hysteresis

Publication Date: 2009.05.26 NAT SEMICON CORP

AI summary

Leakage current at the inputs of an integrated circuit can be reduced by providing a master/slave arrangement wherein a plurality of slave inputs are controlled by an enable input acting as a master. When the enable input is deactivated, the slave inputs break their leakage current paths. An input structure with improved hysteresis can be provided by coupling a follow-on inverter to the output of the input stage, and coupling a hysteresis feedback circuit to the output of the follow-on inverter. The hysteresis feedback circuit is also connected to a node of the input stage other than the output thereof.