Open-Loop DC Bias Circuit for Stable Constant Output

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional constant output DC bias circuits rely on closed loop feedback schemes, which are difficult to stabilize, especially when dealing with multiple high impedance nodes, and require significant power and silicon area, while also being sensitive to temperature, process, and power supply variations.

Innovation Solution

The implementation of an open loop scheme for constant output DC biasing circuits, which eliminates the need for stabilization and generates a DC bias voltage independent of temperature, process, and power supply variations, using a resistor temperature/process variations elimination stage, a transistor temperature/process variations elimination stage, and a current mirror and/or current scaling stage to achieve a constant output DC voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a closed loop feedback scheme is used for constant output DC biasing, then the DC bias voltage can be stabilized, but the circuit becomes difficult to stabilize when there are multiple high impedance nodes in the feedback path

Engineering Contradiction:

ImproveDC bias voltage stabilityVSAvoidcircuit stabilization difficulty

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent inverts the conventional closed-loop feedback approach by using an open-loop scheme. Instead of using feedback to stabilize the DC bias voltage, the invention uses a different architectural approach that eliminates the feedback path entirely, thereby avoiding the stabilization problems associated with multiple high impedance nodes while still achieving constant output DC biasing

Inventive Principle:

Principle #13The other way round (Inversion)

2Stability of the object's composition

If a closed loop feedback scheme is used for constant output DC biasing, then the DC bias voltage can be maintained, but the power consumption and silicon area increase

Engineering Contradiction:

ImproveDC bias voltage constancyVSAvoidpower consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes the feedback loop from the conventional DC biasing circuit. By taking out the closed-loop feedback mechanism, the invention eliminates the associated power consumption and silicon area requirements while maintaining the constant output DC biasing function through an open-loop alternative approach

Inventive Principle:

Principle #2Taking out (Extraction)

3Stability of the object's composition

If a closed loop feedback scheme is used for constant output DC biasing, then the DC bias voltage can be regulated, but the circuit becomes sensitive to temperature, process, and power supply variations

Engineering Contradiction:

ImproveDC bias voltage regulationVSAvoidtemperature, process, and power supply variations

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent addresses the sensitivity issue by inverting the conventional approach. Instead of relying on feedback regulation that is susceptible to environmental variations, the invention employs an open-loop scheme that inherently reduces sensitivity to temperature, process, and power supply variations while maintaining proper DC bias voltage levels

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20110003574A1Constant Output DC Bias Circuit Using an Open Loop Scheme

Publication Date: 2011.01.06 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

Embodiments of the present invention provide constant output DC biasing circuits. Embodiments employ an open loop scheme, instead of a closed loop scheme as used in conventional circuits. In addition, embodiments generate a DC bias voltage that is independent of temperature, process, and power supply variations. Further, embodiments require low amounts of power and silicon.