Internal Voltage Generator Frequency Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional internal voltage generators in semiconductor memory devices fail to maintain a stable internal voltage level as external voltage increases, leading to unreliable operation due to excessive switching current and increased voltage levels.
Innovation Solution
An internal voltage generator is designed with a first level detecting unit, an oscillating unit, a second level detecting unit, a dividing unit, and a charge pumping unit that selectively divides the periodical signal to control the charge pumping frequency, preventing excessive voltage level increases and maintaining a stable internal voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the external voltage VDD is increased to improve power supply capability, then the charge pumping unit pumps more current, but the high voltage VPP becomes unstable and exceeds the target value
Solution Approach 1:
The patent implements a feedback mechanism where the level detecting unit continuously monitors the high voltage VPP level and adjusts the oscillator's operation accordingly. When VPP reaches the target level, the level detecting unit stops the oscillator, preventing over-pumping and maintaining stable voltage despite variations in external voltage VDD.
Solution Approach 2:
The patent makes the charge pumping operation dynamic by controlling the oscillator to operate only when needed. The oscillator is activated when VPP drops below the target level and stopped when it reaches the target, creating a dynamic response that adapts to changing conditions and maintains voltage stability.
2Reliability
If the oscillator operates continuously to maintain high voltage VPP, then the voltage level is maintained, but the switching current becomes excessive when external voltage increases
Solution Approach 1:
The patent employs periodic action by operating the oscillator only during specific periods when voltage supplementation is needed. The level detecting unit triggers the oscillator intermittently based on the actual VPP level, rather than continuous operation, thereby reducing unnecessary switching current while maintaining voltage stability.
3Speed
If the charge pumping unit increases pumping frequency to respond to voltage drops, then the voltage stabilization speed improves, but the switching current increases excessively
Solution Approach 1:
The level detecting unit provides real-time feedback on VPP levels, enabling the oscillator to activate only when voltage drops occur. This feedback-controlled approach achieves fast voltage stabilization by responding immediately to actual voltage conditions while avoiding excessive current draw from unnecessary continuous high-frequency operation.
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
The solution ensures a constant level of internal voltage is maintained despite increases in external voltage, stabilizing the high voltage output and enhancing the reliability of semiconductor memory devices by controlling the charge pumping unit's frequency.
Implementation Method 1
a capacitor C1 for storing electric charges in an output terminal of the inverter I7, and a capacitor C2, which is connected to the supply terminal for the high voltage VPP, for storing the electric charges
Data Source
AI summary
An internal voltage generator is capable of supplying a stable internal voltage regardless of an unstable external voltage. The internal voltage includes a first level detecting unit configured to detect a voltage level of the internal voltage and output an output power detecting signal, an oscillating unit configured to produce a periodical signal in response to the output power detecting signal, a second level detecting unit configured to detect a voltage level of an external voltage and output a driving power detecting signal, a dividing unit configured to selectively divide the periodical signal in response to the driving power detecting signal and output a divided signal, and a charge pumping unit configured to provide the internal voltage by pumping the external voltage in response to the divided signal.