Pre-Amplifier Set for Sense Amplifier Sensing Yield
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Solution Overview
Problem
Conventional sense amplifiers in memory devices experience low sensing yield when the voltage difference between complementary bit lines is small, particularly in memory cells with small resistance, leading to inadequate data sensing and amplification.
Innovation Solution
A set of pre-amplifiers is introduced, comprising a first and second pre-amplifier coupled to the input terminals of a sense amplifier, which perform discharging operations to amplify the voltage difference by terminating the discharging of the other pre-amplifier, utilizing capacitors and switches to control the discharging speeds and amplify the voltage difference between the bit lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sense amplifiers are used without pre-amplifiers, then the device complexity is low, but the sensing yield is low when voltage difference between bit lines is small
Solution Approach 1:
The sensing function is segmented into two stages: pre-amplification stage (performed by first and second pre-amplifiers) and sensing stage (performed by sense amplifier). The pre-amplifiers separately discharge the first and second input terminals through controlled switching, creating amplified voltage difference before the sense amplifier processes the signal. This segmentation enables reliable sensing of small voltage differences while maintaining manageable device complexity through modular architecture.
Solution Approach 2:
The pre-amplifiers perform preliminary discharging action on the input terminals before the sense amplifier operates. By pre-charging the input terminals to predetermined voltage and then controllably discharging them through the pre-amplifiers, the system prepares an amplified voltage difference signal in advance, ensuring the sense amplifier receives a sufficiently large signal for reliable detection.
2Reliability
If pre-amplifiers are added to amplify voltage difference, then the sensing yield improves, but the device complexity increases
Solution Approach 1:
The pre-amplifiers serve multiple functions: they act as voltage amplifiers to enhance the voltage difference between bit lines, function as signal conditioners to prepare the input signal for the sense amplifier, and operate as controllable switches through their switching elements. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving improved sensing yield.
3Speed
If discharging operation is performed on both input terminals simultaneously, then the operation speed is fast, but the voltage difference amplification is insufficient
Solution Approach 1:
The discharging operation is performed periodically and sequentially rather than simultaneously. The control signals switch the switching elements on and off in a periodic manner, first discharging one input terminal, then the other, creating a time-separated discharge pattern. This periodic action maintains fast operation speed while ensuring sufficient voltage difference amplification by preventing simultaneous discharge that would cancel out the voltage difference.
Data Source
AI summary
The present provides a sensing circuit, a set of pre-amplifiers, and an operating method thereof. The set of pre-amplifiers includes a first pre-amplifier and a second pre-amplifier. The first pre-amplifier is coupled to a first input terminal of the sense amplifier. The second pre-amplifier is coupled to a second input terminal of the sense amplifier. The first pre-amplifier and the second pre-amplifier respectively performs a discharging operation to discharge the first input terminal and the second input terminal of the sense amplifier after the first input terminal and the second input terminal of the sense amplifier are charged to a predetermined voltage. One of the first pre-amplifier and the second pre-amplifier amplifies a voltage difference between the first input terminal and the second input terminal of the sense amplifier by terminating the discharging operation of another of the first pre-amplifier and the second pre-amplifier.