IC Voltage Regulator Testing via Feedback Divider Current Control
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Solution Overview
Problem
Current techniques for testing integrated circuit (IC) voltage regulators are inadequate, leading to area penalties, increased costs, and reliability issues due to the need for additional metal pads and the limitations of frontend test architectures.
Innovation Solution
A current-controlled IC voltage regulator testing solution that uses a control current at a feedback divider of each internal supply voltage to alter the internal supply voltage in a linear manner, allowing for the verification of internal IC test circuitry without introducing an area penalty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal pad is added to the IC for testing purposes to override the voltage regulator, then the internal supply voltage can be altered for testing, but this results in a direct area penalty on the IC chip
Solution Approach 1:
The patent reuses the existing test bus and multiplexer infrastructure for voltage regulator testing by injecting control current at the feedback divider. This allows the same test bus to serve multiple functions (testing different voltage regulators) without requiring dedicated metal pads for each regulator, thereby eliminating the area penalty while maintaining comprehensive test coverage
Solution Approach 2:
The patent introduces a feedback divider as an intermediary component that allows indirect control of the internal supply voltage through control current injection. Instead of directly overriding the voltage regulator output, the control current is injected at the feedback divider to linearly adjust the internal supply voltage, enabling precise testing without additional metal pads
2Reliability
If conventional frontend test architecture with metal pads is used, then voltage regulator testing can be performed, but it does not allow for backend testing or debugging in lab
Solution Approach 1:
The patent makes the test bus and multiplexer infrastructure universal by enabling both frontend and backend testing through control current injection at the feedback divider. The same test infrastructure serves multiple testing scenarios (frontend automated testing and backend lab debugging), providing architectural flexibility without requiring separate testing paths
Solution Approach 2:
Instead of using the conventional approach of directly overriding the voltage regulator output at the metal pad, the patent inverts the approach by injecting control current at the feedback divider to indirectly and linearly control the internal supply voltage. This inversion enables more flexible testing architectures including backend testing capabilities
3Reliability
If large currents are used to override the voltage regulator by brute force, then the internal supply voltage can be altered, but this results in heating the metal pad and surrounding region leading to unexpected side effects
Solution Approach 1:
The feedback divider acts as an intermediary that translates small control currents into proportional adjustments of the internal supply voltage. This intermediary mechanism allows precise voltage control using minimal current, avoiding the large currents that cause heating and side effects in brute-force approaches
Solution Approach 2:
The patent changes the control parameter from large voltage override currents to small feedback divider control currents. By operating in the current domain at the feedback divider rather than directly controlling voltage at the output, the system achieves precise voltage regulation with minimal power dissipation and no heating effects
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
This solution enables efficient verification of internal IC test circuitry, reduces area requirements, and improves test reliability by allowing for backend testing and debugging, while minimizing the risk of side effects such as heating.
Implementation Method 1
the control current controls an adjustment of the internal supply voltage, as indicated by a linear relationship between the control current and the internal supply voltage
Data Source
AI summary
The disclosure is directed to the use of an externally-supplied control current to control the adjustment of an internal supply voltage generated via voltage regulator circuitry, which may be identified with an integrated circuit (IC) chip. The configuration of the voltage regulator circuitry functions to establish a linear relationship between the control current and the internal voltage supply. This configuration enables setting the control current to a predetermined value, causing the supply voltage to deviate in a predictable and controllable manner, and thus facilitating verification of the IC chip's internal voltage supply test circuitry. Furthermore, because the control current used for this purpose is relatively small (e.g. on the order of microamps), existing on chip test architecture, which may accommodate such low level currents, may be re-used for the selective routing of the control current for such IC testing.