Test Apparatus Compensation Circuit for Voltage Stability
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Solution Overview
Problem
Existing power supply circuits for testing semiconductor integrated circuits face challenges in stabilizing the power supply voltage due to fluctuations in load current, leading to precision issues in testing and limited responsiveness to rapid changes in power supply voltage.
Innovation Solution
A test apparatus with a compensation circuit that intermittently injects or draws a compensation current via a path different from the main power supply, using a control pattern generator to adjust the duty ratio of the pulse sequence, allowing for effective suppression or induction of power supply voltage fluctuations, and optimizing the compensation current timing to account for delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the power supply voltage is corrected according to a test pattern after reading out the test pattern, then the power supply voltage can be stabilized at the DUT terminal, but the arrangement cannot follow a rapid change in the power supply voltage, leading to a delay in the power supply voltage compensation
Solution Approach 1:
The invention generates the control pattern in advance based on the test pattern before actual testing. This control pattern is then used to drive the compensation circuit to preemptively adjust the power supply voltage, eliminating the delay associated with post-reading correction and enabling rapid response to voltage changes.
Solution Approach 2:
The invention introduces a compensation circuit as an intermediary between the main power supply and the DUT. This compensation circuit, driven by the pre-generated control pattern, actively compensates for voltage fluctuations by injecting or drawing current, thereby stabilizing the power supply voltage at the DUT terminal without requiring post-processing correction.
2Stability of the object's composition
If the compensation circuit is configured as a part of the power supply circuit, then the power supply voltage can be compensated, but the compensation can only be made in the frequency range limited by the impedance between the power supply circuit and the DUT
Solution Approach 1:
The invention segments the power supply system into a main power supply and a separate compensation circuit. The compensation circuit is designed with a different current path that has lower impedance, allowing it to operate effectively at higher frequencies. This segmentation enables the compensation circuit to address high-frequency voltage fluctuations that the main power supply cannot handle.
3Measurement precision
If a multi-bit D/A converter is used according to the range and resolution of the power supply voltage compensation, then the compensation precision can be improved, but the device complexity increases
Solution Approach 1:
The invention uses periodic pulse signals with varying duty ratios to control the compensation circuit instead of requiring a multi-bit D/A converter. By adjusting the duty ratio of the control pattern, the compensation amount can be precisely controlled without complex conversion circuits. This periodic action approach achieves the required compensation precision while significantly reducing device complexity.
Data Source
AI summary
A main power supply supplies a power supply voltage to a power supply terminal of a DUT. A control pattern generator generates a control pattern including a pulse sequence. A compensation circuit intermittently injects a compensation current to the power supply terminal of the DUT via a path different from that of the main power supply. A switch is arranged between an output terminal of a voltage source and the power supply terminal of the DUT, and is turned on and off according to the control pattern.