Semiconductor Memory Device Auxiliary Driver Circuit Stabilization
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Solution Overview
Problem
The fluctuation in the lower write potential in semiconductor memory devices causes delays in sensing operations, particularly in the initial period, due to potential changes in power supply lines, which adversely affect the sensing speed.
Innovation Solution
A semiconductor memory device is designed with an auxiliary driver circuit that supplies a potential lower than the lower write potential to sense amplifiers, along with a second driver circuit for the lower write potential and a first driver circuit for the higher write potential, arranged in specific configurations to minimize potential fluctuations and enhance sensing speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple sense amplifiers are activated simultaneously to perform sensing operations, then productivity is improved, but the lower write potential becomes unstable causing sensing operation delay
Solution Approach 1:
The patent applies preliminary action by activating the lower-potential drive wiring in advance before the higher-potential drive wiring. Specifically, the lower write potential is supplied to the lower-potential drive wiring ahead of time to stabilize it before the sensing operation begins, preventing delays that would otherwise occur during simultaneous activation of multiple sense amplifiers.
Solution Approach 2:
The patent introduces an auxiliary driver circuit as an intermediary component to supply the lower write potential to the lower-potential drive wiring. This auxiliary driver acts as a mediator between the power supply and the drive wiring, ensuring stable potential supply and reducing fluctuations that cause sensing delays.
2Reliability
If the lower write potential is supplied in advance to stabilize sensing operation, then reliability is improved, but the fluctuation in lower write potential still causes delay in initial period
Solution Approach 1:
The auxiliary driver circuit supplies the lower write potential to the lower-potential drive wiring in advance, before the higher-potential drive wiring is activated. This preliminary stabilization of the lower write potential prevents fluctuations during the critical initial period of sensing operation, thereby improving reliability without causing delays.
3Productivity
If sense amplifiers are configured to supply overdrive potential to higher-potential drive wiring, then productivity is improved, but fluctuation in lower write potential has greater adverse influence
Solution Approach 1:
The patent applies the anti-weight principle by introducing the auxiliary driver circuit to counterbalance the harmful effects of lower write potential fluctuations. Just as counterweights offset gravitational forces, the auxiliary driver compensates for potential instability in the lower-potential drive wiring, neutralizing its adverse influence on sensing speed when overdrive potentials are used.
Data Source
AI summary
A semiconductor memory device includes a plurality of sense amplifiers each supplying a higher write potential and a lower write potential to each of memory cells; a driver circuit supplying the higher write potential to each of the sense amplifiers; a driver circuit supplying the lower write potential to each of the sense amplifiers; and an auxiliary driver circuit supplying either the lower write potential or an auxiliary potential lower than the lower write potential to each of the sense amplifiers. It is thereby possible to suppress a fluctuation in the lower write potential at start of a sensing operation. Therefore, the sensing operation can be accelerated as compared with a sensing operation performed by sense amplifiers in a conventional semiconductor memory device.