Memory Bit Line Over-Driver Pulse Control for Core Voltage Stability
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Solution Overview
Problem
Semiconductor memory devices face challenges in maintaining a stable core voltage level during both low and high power voltage conditions, leading to operational characteristic degradation and excessive current supply under high voltage conditions.
Innovation Solution
An over-driver control signal generating unit that adjusts pulse width based on detected supply voltage levels, generating longer pulses under low voltage and shorter pulses under high voltage conditions to prevent excessive voltage increases and ensure stable voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an over-driving scheme is employed to drive the RTO to a higher voltage for a constant time period, then the bit line sensing amplifier can be driven at a higher voltage than the core voltage, but under high power voltage conditions this causes excessive current supply and unstable core voltage levels
Solution Approach 1:
The patent applies dynamics by making the over-driving pulse width variable rather than constant. The control signal generating unit adjusts the pulse width dynamically based on the power supply voltage level: using a first pulse width under low voltage conditions and a second (shorter) pulse width under high voltage conditions. This dynamic adjustment prevents excessive current supply while maintaining stable core voltage levels.
Solution Approach 2:
The patent changes the parameter of pulse width based on the power supply voltage condition. By detecting whether the power supply voltage is at a low level or high level, the system selects appropriate pulse widths from different sets of parameters, thereby optimizing the over-driving effect and preventing voltage instability under different operating conditions.
2Device complexity
If a constant pulse width is used for over-driving regardless of supply voltage conditions, then the control circuit is simple, but the core voltage becomes unstable under high voltage conditions due to excessive current
Solution Approach 1:
The patent introduces dynamic control by using a supply voltage level detecting unit that monitors the power supply voltage and a control signal generating unit that adjusts the over-driving pulse width accordingly. This dynamic approach maintains voltage stability under varying conditions while adding only moderate circuit complexity through standard detection and control components.
3Reliability
If the over-driving pulse width is increased to ensure sufficient driving under low voltage conditions, then the bit line sensing amplifier operates reliably, but under high voltage conditions this causes excessive current and voltage spikes
Solution Approach 1:
The patent changes the pulse width parameter based on supply voltage conditions. Under low voltage conditions, a first (longer) pulse width is used to ensure sufficient driving capability and operational reliability. Under high voltage conditions, a second (shorter) pulse width is used to prevent excessive current and voltage spikes. This parameter adaptation resolves the contradiction between reliability and harmful effects.
Solution Approach 2:
The patent implements feedback by using a supply voltage level detecting unit to monitor the power supply voltage and feed this information back to the control signal generating unit. Based on this feedback, the system automatically adjusts the over-driving pulse width to appropriate levels, preventing harmful effects while maintaining reliability.
Data Source
AI summary
An over-driver control signal generating apparatus includes a pulse generating unit for generating a pulse signal having a pulse width corresponding to a desired over-driving interval in response to an over-driving signal; a supply voltage level detecting unit for detecting a voltage level of a supply voltage to generate a detecting signal; and a selecting unit for outputting the pulse signal as a bit line over-driver control signal in response to the detecting signal.