Power Leakage Sensor Using Frequency Counter for CMOS Defect Detection
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Solution Overview
Problem
Modern CMOS circuits face increasing challenges in detecting power leakage due to rising background leakage, making it difficult to distinguish defects using conventional leakage current measurements.
Innovation Solution
A power leakage sensor system that integrates a power switch controller circuit and a frequency counter circuit within the same die, allowing for the measurement of power supply metrics without additional sensor components, thereby reducing voltage headroom and external connections, and enabling accurate leakage detection by monitoring the frequency of power switch operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional leakage current measurements are used, then power leakage testing can be performed, but the ability to detect defects deteriorates due to increasing background leakage
Solution Approach 1:
The patent introduces an intermediary mechanism (power switch controller and frequency counter) that indirectly measures leakage by monitoring power supply metric variations rather than measuring current directly. This mediator translates the unmeasurably small leakage currents into measurable frequency signals, resolving the contradiction between maintaining measurement capability and dealing with increasing background leakage.
Solution Approach 2:
The patent changes the measurement parameter from direct current measurement to frequency measurement of power supply metric variations. By monitoring how power supply metrics change in response to power switch operations, the system converts an immeasurable parameter (leakage current in high-background environments) into a measurable parameter (frequency of metric variations).
2Measurement precision
If additional sensor components are added to the power supply line, then power leakage measurement capability is improved, but voltage headroom is reduced
Solution Approach 1:
The patent implements self-service by using the circuit's existing power supply infrastructure and inherent metric variations to perform leakage measurement. Instead of adding external sensing components that would consume voltage headroom, the system leverages the power supply line's own characteristics and uses integrated circuits to monitor and interpret its behavior, thereby achieving measurement without additional energy consumption.
Solution Approach 2:
The power supply line serves multiple functions: it provides power to the circuit and simultaneously serves as the measurement medium for detecting leakage. The integrated power switch controller and frequency counter enable the same power supply infrastructure to perform dual roles, eliminating the need for separate sensing components that would reduce voltage headroom.
3Measurement precision
If multiple sub-circuits are tested independently, then measurement accuracy for each sub-circuit is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by associating specific power switches with specific sub-circuits, allowing independent control and measurement of each sub-circuit's leakage characteristics. The power switch controller can selectively activate individual switches to isolate and test particular sub-circuits, enabling precise measurement without requiring separate physical testing systems for each sub-circuit.
Solution Approach 2:
The system uses dynamic control of power switches to enable flexible, reconfigurable testing of different sub-circuits. Rather than requiring static, dedicated testing hardware for each sub-circuit, the dynamic switching mechanism allows a single integrated system to adaptively configure itself for testing different portions of the circuit, reducing overall device complexity while maintaining measurement precision.
Data Source
AI summary
This document discloses a power leakage sensor for a circuit, comprising: a power switch controller circuit coupled with at least one power switch for the digital circuit, the power switch controller configured to control the at least one power switch, to monitor power supply of the digital circuit, and to perform the following: a. in response to the detecting that the power supply to the circuit is powered on, output a power-off signal to the at least one power switch; and b. in response to the measured power supply metric falling below a threshold in response to the power-off signal, output a power-on signal to the at least one power switch. The power leakage sensor further comprises a frequency counter circuit configured to count a frequency of executing steps a. and b., the frequency indicating a proportion of power leakage in the digital circuit.