On-Die Termination Timing Control for Exact Comparison Voltage
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Solution Overview
Problem
Existing on-die termination (ODT) apparatuses for semiconductor memory suffer from errors due to voltage levels not having exact logic values at comparison start times and low voltage issues, leading to incomplete signal matching between bus lines.
Innovation Solution
An improved ODT apparatus with a timing control unit that ensures comparing units operate after initial voltage stabilization, using D/A converting units, counters, and comparing units to adjust codes, and corrects comparison results to achieve exact logic values, even at low power supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the comparing unit operates immediately when the D/A converting unit starts, then the operation speed is fast, but the voltage levels do not have exact logic values causing comparison errors
Solution Approach 1:
The patent applies preliminary action by having the D/A converting unit generate voltages before the comparing unit performs comparisons. The timing control unit coordinates the operation sequence so that voltage generation precedes comparison operations, ensuring stable voltage levels with exact logic values are established before comparison begins, thereby resolving the contradiction between speed and precision.
2Use of energy by moving object
If the comparing unit operates at low power supply voltages, then the energy consumption is low, but the voltage levels are too low to perform normal comparison operations
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the timing of comparison operations based on power supply voltage levels. When power supply voltage is low, the timing control unit delays the start of comparison operations until voltages from the D/A converting unit reach sufficient levels. This allows the system to operate reliably at low power consumption by adapting the comparison timing to the actual voltage conditions rather than using fixed timing.
3Measurement precision
If multiple comparison operations are performed sequentially, then the voltage stabilization is ensured, but the overall operation time increases
Solution Approach 1:
The patent applies periodic action by structuring comparison operations to occur at specific periodic intervals after voltage generation starts. The timing control unit schedules comparison operations at optimized time points where voltages are guaranteed to be stable, allowing multiple comparisons to be performed in a structured periodic manner rather than continuously or randomly, thus balancing precision requirements with time efficiency.
Data Source
AI summary
An on-die termination apparatus for a semiconductor memory according to the invention includes: a first D/A converting unit that outputs a first voltage corresponding to a first code; a first comparing unit that compares the first voltage to a reference voltage and corrects comparison results between the first voltage and the reference voltage, to output first comparison signals, wherein the first comparing unit is operated after a lapse of time from an initial operation time of the first D/A converting unit; a first counter that counts up or down the first code to correspond to the first comparison signals; a second D/A converting unit that outputs a second voltage corresponding to a second code; a second comparing unit that compares the second voltage to the reference voltage and corrects comparison results between the second voltage and the reference voltage, to output seconds comparison signals, wherein the second comparing unit is operated after a lapse of time from an initial operation time of the second D/A converting unit; a second counter that counts up or down the second code to correspond to the second comparison signals; and a timing control unit that controls timings when the first D/A converting unit, the first comparing unit, the first counter, the second D/A converting unit, the second comparing unit, and the second counter start to operate.