Pumping Voltage Control Circuit for DRAM Gate Oxide Protection
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Solution Overview
Problem
Conventional apparatuses for generating pumping voltage in semiconductor devices often result in excessive voltage levels due to electrostatic discharge and noise effects, leading to deterioration of gate oxide films and diminished operational characteristics in DRAMs.
Innovation Solution
An apparatus and method that include a pumping voltage output unit to adjust and maintain a target voltage level, and a release unit to decrease the voltage when it reaches a predetermined excessive level, utilizing a level detecting unit, oscillator, charge pumping unit, and sink unit to control the pumping voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the charge pumping unit continuously pumps voltage to maintain the target level, then the pumping voltage can be restored after electrostatic discharge or noise interference, but the voltage may excessively increase and deteriorate the gate oxide film
Solution Approach 1:
The patent implements a feedback control mechanism where the level detecting unit continuously monitors the pumping voltage level and provides feedback to the oscillator. When the voltage reaches the target level, the feedback signal stops the oscillation, preventing excessive voltage increase. This closed-loop feedback system ensures reliable voltage restoration while avoiding harmful over-voltage conditions that would deteriorate the gate oxide film.
Solution Approach 2:
The patent applies preliminary anti-action by introducing a release unit that activates before excessive voltage can cause damage. The level detecting unit detects when the voltage reaches a predetermined safe level, and the release unit preemptively stops the pumping action, preventing the harmful effect of gate oxide film deterioration before it occurs.
2Reliability
If the pumping enable signal is activated to restore voltage after electrostatic discharge, then the operational characteristics are maintained, but the voltage level becomes higher than the target level by an excessive amount
Solution Approach 1:
The feedback mechanism compares the actual pumping voltage with the target voltage level through the level detecting unit. This feedback control ensures that the voltage is restored to the precise target level without exceeding it, maintaining both operational characteristics and voltage level precision simultaneously.
Solution Approach 2:
The patent employs dynamic control where the oscillator's operation is continuously adjusted based on real-time voltage level detection. The pumping enable signal is dynamically activated or deactivated depending on whether the voltage is below or at the target level, allowing precise voltage control that adapts to changing conditions while maintaining accuracy.
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
Effectively prevents excessive pumping voltage increases, maintaining a stable voltage level and improving the operational reliability and characteristics of DRAMs by actively managing and reducing high voltage levels.
Implementation Method 1
The charge pumping unit 20 generates a pumping voltage VPP in response to the pulse signal osc
Implementation Method 2
The level detecting unit 30 detects the level of the pumping voltage VPP by comparing the pumping voltage VPP with a reference voltage VREF
Data Source
AI summary
A device for generating a pumping voltage and preventing an excessive increase in the pumping voltage includes a pumping voltage output unit that outputs a pumping voltage and adjusts the level of the pumping voltage in order to maintain a target voltage. The level of the pumping voltage is adjusted in response to a change in the level of the pumping unit. A release unit is included to detect an excessive pumping voltage. The release unit adjusts the level of the pumping voltage when the pumping voltage reaches a predetermined excessive level by compulsively decreasing the pumping voltage to prevent damage in the DRAM.