Power Line Switching Circuit for Reliable Semiconductor Test Modes
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Solution Overview
Problem
Existing semiconductor devices require expensive testing equipment to coordinate control circuits for power gating and test operations, leading to inadequate stress application during accelerated tests and data transfer issues during input/output tests due to uncoordinated power gating functions.
Innovation Solution
A semiconductor device with a mode switching circuit that couples or isolates power lines based on signal logical values, allowing for independent operation of internal circuits during test and normal modes, eliminating the need for expensive testing equipment by ensuring consistent power supply and voltage levels for accelerated testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a control circuit performs power gating operation to reduce power consumption, then power consumption decreases, but test operations cannot be properly performed without expensive testing equipment
Solution Approach 1:
A mode switching circuit is introduced as an intermediary between the power gating control circuit and the power supply. This mediator receives the power gating control signal and selectively responds to it based on the operational mode (test or normal), thereby decoupling the power gating function from test operations without requiring expensive external testing equipment.
Solution Approach 2:
The power supply connection is made dynamic through the mode switching circuit, which can change its state based on operational mode. During test operations, the switching circuit maintains power supply connection regardless of power gating signals, while during normal operations, it allows power gating to function. This dynamic behavior enables reliable test operations while preserving power consumption benefits in normal mode.
2Reliability
If expensive testing equipment is used to generate control signals for coordinating control circuits, then test operation reliability improves, but device complexity and cost increase
Solution Approach 1:
The semiconductor device performs its own test coordination functions through the mode switching circuit that is integrated within the device. Instead of relying on expensive external testing equipment to generate and coordinate control signals, the device uses its own internal resources and signals to manage power supply during test operations, thereby reducing external equipment requirements and overall system complexity.
3Use of energy by moving object
If power gating function is activated during test operations, then power consumption is reduced, but stress application and data transfer are compromised
Solution Approach 1:
The power supply connection is made dynamic through the mode switching circuit, which can change its state based on operational mode. During test operations, the switching circuit maintains power supply connection regardless of power gating signals, while during normal operations, it allows power gating to function. This dynamic behavior enables reliable test operations while preserving power consumption benefits in normal mode.
Data Source
AI summary
A semiconductor device whose operational state is switched between a test state and a normal operational state according to a logical value of a signal input from the outside is provided. The semiconductor device includes a first power line, a second power line, a switch that is controlled by a signal line to couple/isolate the first power line to/from the second power line, a control circuit that outputs a control signal, and a state switching circuit that drives the signal line to couple/isolate the first power line to/from the second power line according to a logical value of the control signal when the input signal is one of logical values, whereas the state switching circuit drives the signal line to couple the first power line to the second power line when the first signal is the other logical value.