Stacked Sense Amplifier Circuit for Low-Voltage Noise Reduction
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Solution Overview
Problem
Existing sense amplifiers struggle with high kickback noise and require higher minimum operating voltages, which affect signal accuracy and speed.
Innovation Solution
A sense amplifier design utilizing a stacked configuration of three transistors, where the source terminals of p-channel transistors are coupled to a fixed voltage, reducing kickback noise and allowing operation at lower voltages and increased speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional four-transistor amplifier configuration is used, then signal amplification capability is maintained, but kickback noise increases and minimum operating voltage requirement increases
Solution Approach 1:
The amplifier is divided into two separate stages: a differential pair stage for signal reception and a push-pull output stage for amplification. This segmentation isolates the differential pair from the output loading effects, reducing kickback noise while maintaining signal accuracy. The intermediate coupling through current mirrors further decouples the stages, preventing noise feedback.
Solution Approach 2:
Current mirror circuits are introduced as intermediary elements between the differential pair and the push-pull output stage. These current mirrors act as buffer intermediaries that transfer signals while isolating the differential pair from output disturbances, thereby reducing kickback noise without compromising signal fidelity.
2Use of energy by moving object
If traditional four-transistor amplifier configuration is used, then signal amplification is achieved, but minimum operating voltage increases
Solution Approach 1:
The amplifier employs dynamic biasing through current mirrors that automatically adjust operating currents based on signal conditions. This dynamic operation allows the amplifier to maintain high speed performance at lower voltage levels by optimizing current flow in real-time, rather than requiring high static voltage margins.
Solution Approach 2:
The invention changes the operating parameters by using current-mode operation instead of voltage-mode operation. This parameter change allows the amplifier to achieve higher speed at lower voltages by controlling signal flow through current mirrors and active loads, fundamentally altering the voltage-speed relationship.
3Object-affected harmful factors
If stacked three-transistor configuration is used, then kickback noise is reduced and operating voltage is lowered, but circuit complexity increases
Solution Approach 1:
The current mirror circuits serve multiple functions simultaneously: they provide signal buffering, impedance transformation, and isolation between stages. This multi-functionality reduces the need for separate dedicated components, thereby managing circuit complexity while achieving noise reduction and voltage lowering benefits.
Solution Approach 2:
The invention merges the functions of multiple traditional amplifier components into a unified stacked transistor configuration. The differential pair, active loads, and current mirrors are combined into a compact stacked architecture that achieves noise reduction and voltage reduction while consolidating circuit elements rather than increasing overall complexity.
Data Source
AI summary
A sense amplifier includes a first pair of transistors having gate terminals respectively coupled to a first input terminal for receiving a first input signal and to a second input terminal for receiving a second input signal, source terminals coupled to a first power supply terminal, and drain terminals. The sense amplifier also includes a second pair of transistors having gate terminals coupled to a clock terminal, source terminals respectively coupled to the drain terminals of the first pair of transistors, and drain terminals. The sense amplifier also includes a third pair of transistors having gate terminals coupled to the clock terminal, drain terminals respectively coupled to the drain terminals of the second pair of transistors, and source terminals coupled to a second power supply terminal. In addition, the sense amplifier includes an output circuit coupled to the drain terminals of the second pair of transistors and having an output terminal.