Integrated Circuit Input Terminal Testing via Switchable Current Source
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Solution Overview
Problem
Existing integrated circuits face challenges in testing internal signals without additional terminals, leading to increased test time and economic costs due to the indirect and delayed reflection of internal signals in output signals, which hinders efficient production line testing.
Innovation Solution
A first circuit section with a control input that changes its current-voltage characteristic in response to a control signal, allowing for the evaluation of internal signal changes without additional terminals by applying an electrical test signal and using switchable current sources or resistors to reflect internal signal changes in input behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional terminals are added to tap internal signals for testing, then measurement precision is improved, but device complexity and area increase
Solution Approach 1:
The existing input terminal is made multi-functional by enabling it to serve both as a normal input terminal and as a test terminal for detecting internal signals. The circuit section modifies the input terminal's behavior based on a control signal, allowing the same physical terminal to perform different functions without requiring additional terminals, thus resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
A circuit section is introduced as an intermediary between the internal signal and the input terminal. This circuit section includes a switchable current source that mediates the relationship by allowing the input terminal to reflect internal signal states through controlled current variations, enabling internal signal detection without direct terminal access
2Device complexity
If internal signals are detected through output signal analysis, then device complexity is reduced, but measurement time increases
Solution Approach 1:
The circuit section is configured to prepare the input terminal in advance for test mode by using a control signal to activate the switchable current source. This preliminary setup allows the input terminal to be ready for immediate internal signal detection without requiring complex test sequences or additional time for signal routing, thus reducing measurement time while maintaining simplicity
3Measurement precision
If switchable current sources are used to reflect internal signals, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The switchable current source is activated periodically or on-demand based on test requirements rather than continuously. The control signal enables the current source to operate only when internal signal detection is needed, reducing overall energy consumption while maintaining the ability to provide precise measurements when required, thus resolving the contradiction between measurement precision and energy use
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
Enables the detection of internal signal state changes without additional terminals, reducing measurement time and costs by reflecting internal signal changes in input behavior, thus improving production efficiency.
Implementation Method 1
A first circuit section is provided that has a control input for a control signal and is designed to change its current-voltage characteristic when the control signal is present at the control input
Data Source
AI summary
An integrated circuit is disclosed having at least one digital input, which has a first circuit section that has a current-voltage characteristic and that in the absence of an input signal holds a voltage at the input at a defined value, and having a second circuit section that provides a signal that is internal to the circuit and whose state does not directly show itself at an output of the circuit. The first circuit section has a control input for a control signal and is designed to change its current-voltage characteristic when the control signal is present at the control input. In addition, a method for testing such a circuit is disclosed.