Power Switch Fault Detection Using Dual Storage Circuits

Solution Overview

Problem

Manufacturing defects in power switch circuitry, such as always-ON or always-OFF states, are not detected by typical testing methods, leading to increased power consumption and potential overheating in battery-operated devices, which can result in shorter battery life and device failure.

Innovation Solution

Incorporating a first data storage circuit to set and control the ON/OFF state of the power switch and a second data storage circuit to capture the actual state during testing, allowing for the detection of defects like always-ON behavior by applying a control signal and evaluating the voltage level at the bias terminal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If typical testing methods are used for power switch circuitry, then the testing process is simple, but manufacturing defects such as always-ON or always-OFF states are not detected

Engineering Contradiction:

Improvedefect detection capabilityVSAvoidtesting circuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-configuring the power switch in a known state (OFF state) before testing, and by preparing test circuits in advance that can capture the switch state. The test circuit includes a capture circuit that is ready to latch the power switch state, and a control circuit that pre-establishes the expected state for comparison. This allows defect detection without adding complex real-time monitoring during operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediary elements including a capture circuit that mediates between the power switch and the test logic, and a comparison circuit that acts as an intermediary to compare the captured state with the expected state. These intermediary circuits simplify the overall testing architecture by breaking down the complex detection task into manageable stages: capture, hold, and compare.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of energy

If power gating is implemented to reduce leakage power consumption, then power management is improved, but undetected manufacturing defects can cause increased power consumption and overheating

Engineering Contradiction:

Improveleakage power consumptionVSAvoidpower switch reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent implements feedback by creating a closed-loop test system that monitors the actual state of the power switch and compares it with the expected state. The test circuit captures the power switch state, compares it with the commanded state, and generates a pass/fail indication. This feedback mechanism ensures that any deviation from expected behavior (such as always-ON defects) is detected and reported, preventing undetected power consumption issues.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by pre-configuring the power switch in a known state (OFF state) before testing, and by preparing test circuits in advance that can capture the switch state. The test circuit includes a capture circuit that is ready to latch the power switch state, and a control circuit that pre-establishes the expected state for comparison. This allows defect detection without adding complex real-time monitoring during operation.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If no specific test for power switch state is implemented, then the manufacturing process is faster, but defects lead to shorter battery life and potential device failure

Engineering Contradiction:

Improvemanufacturing test speedVSAvoiddevice reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-configuring the power switch in a known state (OFF state) before testing, and by preparing test circuits in advance that can capture the switch state. The test circuit includes a capture circuit that is ready to latch the power switch state, and a control circuit that pre-establishes the expected state for comparison. This allows defect detection without adding complex real-time monitoring during operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical or invasive testing methods with electrical signal-based testing. Instead of physically manipulating or disassembling devices to test power switches, the invention uses electrical signals to command switch states and capture actual states, comparing them electronically to detect defects. This substitution maintains manufacturing speed while improving reliability detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS7944285B1Method and apparatus to detect manufacturing faults in power switches

Publication Date: 2011.05.17 CADENCE DESIGN SYST INC

AI summary

An integrated circuit is provided that comprises a power switch that includes a control terminal and that is coupled between a power source node and a power sink node; first data storage circuit includes a data storage input and a data storage output, wherein the data storage output is coupled to the power switch control terminal; and a second data storage circuit includes a data storage input and a data storage output, wherein the data storage input is coupled to the power sink node.