IC Output Stage On-Resistance Test Circuit
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Solution Overview
Problem
Existing methods for testing the on-resistance of transistors in integrated circuits (ICs) are limited, as they require a common power line and cannot be applied to multi-power ICs or those with different power lines, and they complicate the structure when the IC power voltage is high.
Innovation Solution
A test circuit with a test controller that switches between normal and test modes, using a level shifter and switch elements to control the activation and deactivation of output stages, allowing for four-terminal measurement of on-resistance across multiple output stages connected to independent power lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a common power line (VDD line) is used to connect DUT and reference device for four-terminal measurement, then the test can be conducted with simple circuit connection, but the test cannot be conducted when the VDD line is broken and the method cannot be applied to multi-power ICs
Solution Approach 1:
The patent divides the power supply connection into separate independent power lines for each output stage being tested, rather than using a common power line. This segmentation allows each output stage to be tested independently even when other power lines are broken or have different voltage levels, thereby improving both adaptability and reliability.
Solution Approach 2:
The test circuit is designed to universally handle both single-power ICs and multi-power ICs by accommodating different power line configurations. The circuit can adapt to various power supply scenarios including broken power lines and different voltage levels, making it applicable to a broader range of IC types without requiring separate testing methodologies.
2Measurement precision
If separate test circuits are designed for multi-power ICs with different power levels, then the test can be conducted accurately, but the structure becomes complicated and requires additional voltage sources
Solution Approach 1:
The test circuit utilizes the existing power lines and voltage sources already present in the IC under test to perform the measurements. By self-service, the circuit eliminates the need for external additional voltage sources or complex auxiliary power supply circuits, thereby maintaining measurement precision while significantly reducing circuit complexity.
Solution Approach 2:
The patent combines the test function with the existing output stages and power lines of the IC. The test controller integrates the control of multiple output stages, and the measurement circuitry utilizes the existing power infrastructure, merging the test functions with the device's operational structures to avoid adding separate complex test circuits.
3Adaptability or versatility
If multiple output stages are tested simultaneously with separate switch elements, then each stage can be measured independently, but the number of control signals and circuit elements increases
Solution Approach 1:
The test controller is designed as a universal control unit that can manage and coordinate multiple output stages through a standardized control interface. This multi-functional controller reduces the need for separate dedicated control circuits for each output stage, thereby maintaining independent measurement capability while reducing overall circuit complexity.
Solution Approach 2:
The test circuit employs dynamic switching of output stages under test, where the test controller selectively activates and deactivates different output stages as needed. This dynamic approach allows a single set of measurement circuits to serve multiple functions across different time periods, reducing the need for parallel static measurement paths and associated control signals.
Data Source
AI summary
A test controller switches the operation of output stages in an integrated circuit between a normal operation mode and a test mode. The output stages are respectively connected to switch elements. A level shifter generates a switch signal for controlling activation and deactivation of the switch elements in accordance with the normal operation mode and the test mode.