Semiconductor Memory Word Line Voltage Control
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Solution Overview
Problem
Conventional semiconductor memory devices face challenges in reducing power consumption due to high current consumption when activating word lines from ground voltage to boosted voltage, especially as memory capacity increases, leading to instability in voltage levels and difficulty in designing low-power devices.
Innovation Solution
The semiconductor memory device employs a voltage supplying unit that outputs a power source voltage for a predetermined time before switching to a high voltage, activating the word line in consecutive order with external voltage VDD and high voltage VPP, stabilizing the voltage level and reducing power consumption by controlling the activation timing based on an external clock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high voltage VPP is used to activate word lines in conventional semiconductor memory devices, then the word line can be activated to achieve high-speed operation, but current consumption increases significantly and voltage instability occurs
Solution Approach 1:
The patent applies preliminary action by first activating the word line with external voltage VDD before switching to high voltage VPP. The voltage supplying unit initially supplies VDD to the word line, then after a predetermined time period, switches to supplying VPP. This preliminary activation with lower voltage reduces the inrush current and allows gradual voltage transition, thereby reducing current consumption while maintaining the ability to achieve high-speed operation with VPP
Solution Approach 2:
The patent implements periodic action through time-controlled voltage switching. The voltage supplying unit operates in periodic cycles: first supplying external voltage VDD for a predetermined time period, then switching to supply high voltage VPP. This periodic voltage application pattern allows the system to benefit from both low-current initial activation and high-voltage performance enhancement while managing current consumption through controlled timing
2Speed
If high voltage VPP is used to activate word lines, then high-speed operation is achieved, but voltage level instability occurs
Solution Approach 1:
The patent uses preliminary action to stabilize voltage levels by first establishing the word line at external voltage VDD before transitioning to high voltage VPP. This preliminary voltage establishment allows capacitive elements and circuit nodes to prepare for the voltage transition, reducing voltage spikes and instability that would occur with direct high-voltage activation. The predetermined time period allows proper voltage settling before the switch to VPP
3Adaptability or versatility
If multiple boosted voltage generating circuits are included to provide various voltages, then voltage flexibility is improved, but chip area increases
Solution Approach 1:
The patent applies universality by designing the voltage supplying unit to perform multiple functions: it can supply both external voltage VDD and boosted voltage VPP to the word line, and can switch between these voltage sources. This multi-functional voltage supplying unit eliminates the need for separate dedicated circuits for each voltage source, thereby providing voltage flexibility while minimizing chip area occupation
Solution Approach 2:
The patent merges the functionality of multiple voltage sources into a single voltage supplying unit. Instead of having separate circuits for VDD and VPP generation and switching, the patent combines these functions into one unified voltage supplying unit that can selectively output either VDD or VPP based on operational requirements, thereby reducing overall chip area while maintaining voltage generation flexibility
Data Source
AI summary
A semiconductor memory device which includes: a voltage supplying unit for outputting a power source voltage as a driving source signal during a predetermined time, and then outputting a high voltage as the driving source signal in response to a driving control signal activated in response to an address signal; and a word line control unit for activating a word line at a voltage level of the driving source signal in response to the driving control signal.