Multi-Stage Amplifier Dynamic Biasing for Lower OTA Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing analog-to-digital converters (ADCs) using switched capacitor (SC) amplifiers with operational transconductance amplifiers (OTAs) face high power consumption, leading to low power efficiency.
Innovation Solution
A multi-stage amplifier circuit with dynamic biasing, comprising a first and second multi-stage amplifier circuit, each including a second and third stage transistor, a bias transistor, and a dynamic switching circuit, which samples bias voltages across capacitors and biases the transistors accordingly in different phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If operational transconductance amplifiers (OTAs) are used in switched capacitor amplifiers, then amplification performance is achieved, but power consumption increases
Solution Approach 1:
The amplifier is divided into multiple stages (first stage, second stage, third stage) with each stage performing specific functions. The first stage performs initial amplification, while subsequent stages perform dynamic biasing and signal processing, allowing power to be distributed and optimized across stages rather than concentrated in a single high-power OTA
Solution Approach 2:
The patent employs periodic switching between first and second phases for dynamic biasing. During the first phase, bias voltages are sampled and stored; during the second phase, these bias voltages are applied to optimize transistor operation. This periodic action allows the amplifier to achieve high performance only when needed while consuming minimal power during biasing phases
Solution Approach 3:
The patent implements dynamic biasing where bias voltages are adjusted periodically rather than being fixed. The dynamic switching circuit changes the operating point of transistors based on the phase, allowing the amplifier to adapt its power consumption and performance characteristics dynamically rather than operating at constant high power levels
2Use of energy by moving object
If dynamic biasing with multiple stages is implemented, then power efficiency is improved, but device complexity increases
Solution Approach 1:
The dynamic switching circuit serves multiple functions: it switches between different biasing configurations, samples bias voltages, and controls the operation mode of transistors across different phases. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby managing complexity while achieving power efficiency
Solution Approach 2:
The patent combines the biasing circuitry with the signal processing stages. The same transistors and capacitors used for signal amplification are also utilized for bias voltage sampling and storage during different phases. This merging of functions reduces the total component count and circuit complexity compared to having separate biasing circuits
Data Source
AI summary
An amplifier includes a first stage amplifier circuit configured to receive an input voltage and a first multi-stage amplifier circuit and a second multi-stage amplifier circuit branching off from an output terminal of the first stage amplifier circuit and each including a second stage and a third stage. Each of the first multi-stage amplifier circuit and the second multi-stage amplifier circuit may be configured to sample a voltage corresponding to a first bias current corresponding to the second stage and a voltage corresponding to a second bias current corresponding to the third stage in a first phase, and bias the second stage with the voltage corresponding to the first bias current and bias the third stage with the voltage corresponding to the second bias current in a second phase.