High-Speed Amplifier Inductance Network for Pole Frequency Boost
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Solution Overview
Problem
High-speed amplifiers face challenges in increasing non-dominant pole frequencies without increasing power consumption, as existing methods to enhance transconductance are limited by manufacturing processes and lead to under-damped behavior and low bandwidth.
Innovation Solution
Incorporating an inductance network with an inductor connected to the transistors at the source node to compensate for output capacitance, forming a parallel RLC resonant circuit that increases the non-dominant frequency pole without increasing current, using inductors with values between 100 pico-Henry and 350 pico-Henry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If current in the output stage is increased to increase gm, then non-dominant pole frequency is improved, but power consumption increases
Solution Approach 1:
An inductance network is introduced as an intermediary element connected to the output node. This inductor compensates for the output capacitance by forming a resonant circuit, effectively pushing the non-dominant pole to higher frequencies without requiring increased output stage current, thus avoiding additional power consumption
Solution Approach 2:
The invention changes the electrical parameters at the output node by introducing inductance. By adding the inductance network with specific inductance values (100-350 pH), the pole frequency is adjusted through parameter modification rather than through current increase, resolving the contradiction between speed improvement and power consumption
2Speed
If gm/C is increased by process limitations, then non-dominant pole frequency is improved, but manufacturing complexity increases
Solution Approach 1:
Rather than relying on process modifications to change transistor characteristics, the invention uses an external inductance network as a mediator to achieve the desired frequency response. This approach avoids complex manufacturing process changes while still improving the non-dominant pole frequency
Solution Approach 2:
Instead of trying to improve gm/C through transistor parameter changes in the same dimensional space (requiring process modifications), the invention moves to another dimension by adding an inductance element, creating a new degree of freedom for pole frequency adjustment without affecting manufacturing complexity
3Use of energy by moving object
If low non-dominant pole frequency is accepted, then power consumption is reduced, but phase margin deteriorates and bandwidth decreases
Solution Approach 1:
The inductance network acts as a compensating intermediary that improves phase margin and bandwidth characteristics without requiring increased power consumption. By forming a resonant circuit with the output capacitance, it provides the necessary phase boost to improve stability margins
Solution Approach 2:
The invention converts the harmful effect of output capacitance (which limits pole frequency and bandwidth) into a beneficial resonant circuit when combined with the inductance network. The capacitance that would normally degrade performance becomes part of a tuned circuit that improves overall amplifier performance at lower power consumption
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively increases the non-dominant pole frequency and improves bandwidth and settling time while reducing power consumption by approximately 40% compared to achieving similar response without the inductance network.
Implementation Method 1
Incorporating an inductance network with an inductor connected to the transistors at the source node to compensate for output capacitance, forming a parallel RLC resonant circuit that increases the non-dominant frequency pole
Data Source
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AI summary
A circuit may include one or more transistors (110) connected directly to an output, and an inductance network (120). The inductance network may connect to a source node of at least one of the transistors, to compensate capacitance of the output. Thus, the response time of the circuit may decrease, and a non-dominant frequency response pole frequency of the circuit may increase.