Self-Biased Gain-Boosted Op-Amp With Subthreshold Biasing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing operational amplifier circuits require multiple external biasing voltages, leading to increased area and power consumption, as well as susceptibility to noise and cross-talk.
Innovation Solution
The proposed amplifier circuit employs a self-biased, gain-boosted configuration using a resistive element to place drive transistors in the subthreshold region, reducing the need for external biasing voltages and minimizing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple external biasing voltages are used in operational amplifier circuits, then the amplifier can achieve proper operation and gain, but the area and power consumption increase
Solution Approach 1:
The amplifier circuit uses self-biasing where the drive transistors automatically establish their own operating points through resistive coupling between stages. The circuit generates its own bias conditions internally without requiring multiple external biasing voltages, thereby reducing area while maintaining proper amplifier operation
Solution Approach 2:
The patent extracts and eliminates the need for multiple external biasing voltage sources by implementing a self-biasing architecture. The biasing function is integrated into the amplification stages themselves through resistive coupling, removing the separate biasing circuitry and reducing overall circuit area
2Reliability
If multiple external biasing voltages are used in operational amplifier circuits, then the amplifier can achieve proper operation and gain, but power consumption increases
Solution Approach 1:
The amplifier circuit uses self-biasing where the drive transistors automatically establish their own operating points through resistive coupling between stages. The circuit generates its own bias conditions internally without requiring multiple external biasing voltages, thereby reducing area while maintaining proper amplifier operation
Solution Approach 2:
The patent extracts and eliminates the need for multiple external biasing voltage sources by implementing a self-biasing architecture. The biasing function is integrated into the amplification stages themselves through resistive coupling, removing the separate biasing circuitry and reducing overall circuit area
3Device complexity
If traditional amplifier configurations are used, then the circuit is simpler, but noise susceptibility and cross-talk increase
Solution Approach 1:
The patent introduces resistive coupling elements as intermediaries between amplifier stages. These resistors act as isolation barriers that reduce cross-talk between stages while maintaining signal transmission, and they provide noise filtering benefits without significantly increasing circuit complexity
Solution Approach 2:
The patent places drive transistors in the subthreshold region by adjusting bias conditions through resistive coupling. This parameter change in transistor operating region reduces noise susceptibility and improves signal integrity while maintaining acceptable circuit complexity
4Power
If drive transistors operate in standard region, then the amplifier provides adequate gain, but DC gain is limited and power consumption is higher
Solution Approach 1:
The patent places drive transistors in the subthreshold region by adjusting bias conditions through resistive coupling. This parameter change in transistor operating region reduces noise susceptibility and improves signal integrity while maintaining acceptable circuit complexity
Solution Approach 2:
The patent places drive transistors in the subthreshold region by adjusting bias conditions through resistive coupling. This parameter change in transistor operating region reduces noise susceptibility and improves signal integrity while maintaining acceptable circuit complexity
Data Source
AI summary
A first embodiment is directed to a circuit including a positive biasing circuit with a drive PMOS for biasing in subthreshold, a negative biasing circuit with a drive NMOS for biasing in subthreshold, and an amplification circuit coupled to the biasing circuits. The amplification circuit includes a first stage with a first boosting stage, a second stage with a second boosting stage, and a resistive element coupled between the first and second stages. A second embodiment is directed to a folded cascode operational amplifier wherein a value of the resistive element is selected to place at least one of a drive MOS in subthreshold. A third embodiment is directed to an integrated circuit with a resistive area neighboring a first boosting area and a second boosting area, the resistive area including a resistive element directly connected to a drive PMOS and a drive NMOS.