Dynamic Amplifier Circuit With Current Mirror for Large Output Swing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Dynamic amplifiers face challenges in achieving a large output swing due to the proportional relationship between the fall of output voltage and the rise of source voltage, limiting the extent to which the output voltage can fall.
Innovation Solution
Incorporating a current mirror and load capacitor in the dynamic amplifier design, along with specific switch configurations and voltage resetting signals, allows for a larger output swing by decoupling the output voltage from the source voltage, enabling the output voltage to approach the power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a dynamic amplifier uses a proportional relationship between output voltage fall and source voltage rise, then the circuit structure is simple, but the output swing is limited
Solution Approach 1:
The amplifier is divided into two independent phases: reset phase and amplification phase. During reset phase, switches connect the source node to VDD and drain node to ground to initialize voltages. During amplification phase, switches disconnect to allow independent voltage changes. This temporal segmentation allows the output voltage to swing independently from source voltage, resolving the contradiction between simple structure and limited output swing.
Solution Approach 2:
The circuit uses time-varying switch configurations to dynamically change the circuit topology between reset and amplification phases. The switches are controlled by clock signals to enable dynamic reconfiguration, allowing the amplifier to achieve large output swing during amplification while maintaining simple circuit structure through controlled dynamic operation.
2Ease of operation
If the output voltage is coupled to the source voltage, then the circuit operation is straightforward, but the gain is limited
Solution Approach 1:
The amplifier operates in periodic two-phase cycles: reset phase followed by amplification phase. During reset phase, capacitors are charged to initialize conditions. During amplification phase, the coupled capacitors transfer charge to generate amplified output. This periodic operation enables high gain by accumulating charge transfer effects over each cycle while maintaining straightforward circuit operation through repeated identical cycles.
Data Source
AI summary
A dynamic amplifier includes a common-source amplifier configured to receive a gate voltage at a gate node and output a drain current to a drain node; a current mirror configured to mirror the drain current into an output current to an output current; a source capacitor connected to the source node; a load capacitor connected to the output node; a first switch configured to conditionally connect the gate node to an input voltage; a second switch configured to conditionally connect the gate node to a gate-resetting voltage; a third switch configured to conditionally connect the source node to a source-resetting voltage; a fourth switch configured to conditionally connect the drain node to a drain-resetting voltage; and a fifth switch configured to conditionally connect the output node to an output-resetting voltage.