Current-Injected Telescopic Amplifier for Higher Bandwidth
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Solution Overview
Problem
Conventional operational amplifiers face a bandwidth limit due to parasitic capacitance, which cannot be significantly reduced without increasing device size, leading to a trade-off between bandwidth and power consumption.
Innovation Solution
The implementation of current injection in a telescopic operational amplifier configuration, where additional current sources inject currents into the input stage, allowing for a decrease in device size and parasitic capacitance without increasing power consumption or circuit area, thereby enhancing bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If device size is increased to reduce parasitic capacitance, then bandwidth is improved, but power consumption and circuit area increase
Solution Approach 1:
The patent changes the electrical parameters of the circuit by injecting current into the input stage, which modifies the effective transconductance and allows bandwidth improvement without changing the physical device dimensions. This parameter change enables decoupling the bandwidth from device size constraints
Solution Approach 2:
The patent introduces current injection as an intermediary mechanism that mediates between the conflicting requirements of bandwidth and power consumption. The injected current acts as a mediator that enhances the effective signal without requiring larger physical devices, thus avoiding increased power consumption
2Speed
If device size is increased to reduce parasitic capacitance, then bandwidth is improved, but circuit area increases
Solution Approach 1:
The patent modifies circuit parameters through current injection to achieve bandwidth improvement without increasing the physical footprint. By changing the effective transconductance parameter, the circuit achieves higher bandwidth within the same area constraints
Solution Approach 2:
Current injection serves as an intermediary that enables bandwidth enhancement without requiring additional circuit area. The injected current mediates the relationship between bandwidth and area, allowing improvement in one without sacrificing the other
3Speed
If parasitic capacitance is reduced by decreasing device size, then bandwidth is improved, but transconductance decreases
Solution Approach 1:
The patent compensates for the decrease in transconductance caused by smaller device size through current injection. By injecting current into the input stage, the effective transconductance is enhanced, maintaining the necessary gain while benefiting from reduced parasitic capacitance
Solution Approach 2:
The patent converts the harmful effect of reduced transconductance (caused by smaller devices) into a benefit. The current injection mechanism transforms the limitation into an opportunity to achieve both low parasitic capacitance and sufficient transconductance simultaneously
Data Source
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AI summary
An amplifier with increased bandwidth by current injection and a method thereof. The amplifier includes an input stage (22) for receiving a first input signal, a load stage (24) coupled to the input stage (22) for generating a first output signal, a first current source (M9) coupled to the input stage (22) for allowing a predetermined current to flow, and a second current source (26,28), coupled to the input stage (22), for injecting a first current into the input stage for outputting the first output signal.