Sense Amp Power Noise Reduction in Memory Sensing
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Solution Overview
Problem
Sensing operations in memory devices, such as NAND flash memory, are prone to inaccuracies due to sense amplifier supply power noise, which affects the determination of storage element states and leads to broader threshold voltage distributions.
Innovation Solution
The method involves controlling sense modules by coupling a power supply to storage elements through distinct conductive paths and using a common power supply for multiple sense modules, allowing for staggered A/D conversions to minimize power noise and maintain consistent power draw during sensing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common power supply is used for multiple sense modules, then device complexity is reduced, but power noise increases and affects sensing accuracy
Solution Approach 1:
The patent divides the power supply into separate dedicated power supplies for each sense module rather than using a common power supply. This segmentation isolates the power noise in one module from affecting other modules, thereby maintaining sensing accuracy while managing the complexity through modular architecture.
Solution Approach 2:
The patent introduces separate power supply circuits as intermediaries between the main power source and each sense module. These intermediary power supplies act as isolation barriers that prevent power noise propagation while maintaining the functional connection between power and sensing components.
2Productivity
If sense modules are operated simultaneously, then productivity is improved, but power noise increases and reduces measurement precision
Solution Approach 1:
The patent segments the sensing operations into time-multiplexed cycles where different sense modules are activated sequentially rather than simultaneously. This temporal segmentation allows multiple sensing operations to proceed in parallel across different time slots, maintaining productivity while preventing power noise interference between modules.
Solution Approach 2:
The patent implements periodic operation where sense modules are activated in alternating cycles. Each sense module operates during its designated time period, then enters a quiet period while other modules operate. This periodic action pattern maintains system throughput while isolating power noise effects to specific time windows.
Data Source
AI summary
In a sensing method, accuracy of sensing operations, such as read or verify, in a memory device is improved by avoiding fluctuations in a sense amp supply voltage which can occur when different sense amps are strobed at different times. First and second sets of sense amps perform a sensing operation on respective storage elements, such as in an all bit line configuration. The first set of sense amps is strobed at a first time point. In response, a sensed analog level is converted to digital data. The A/D conversion relies on the sense amp supply voltage being accurate. To avoid a fluctuation in the sense amp supply voltage, a bypass path allows the storage elements associated with the first set of sense amps to continue to draw power from the sense amp supply voltage. The second set of sense amps is strobed at a later, second time point.