Transconductance Circuit Current Cells for Precision and Noise Cancellation
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Solution Overview
Problem
Conventional transconductance circuits face limitations in generating precise output currents while minimizing area and power consumption, and struggle with driving loads having large inductance, particularly in applications like optical vital signs measurement, where noise cancellation is challenging.
Innovation Solution
The proposed transconductance circuits incorporate an amplifier with switches and a programmable capacitor to control current output, allowing for a wide range of precision currents and simultaneous monitoring of output current and voltage to cancel noise, utilizing multiple current cells and feedback loops to manage load drive capability and noise adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional transconductance circuits are used to generate precise output currents, then current precision is improved, but area and power consumption increase
Solution Approach 1:
The transconductance circuit is divided into multiple current cells (first current cell, second current cell, etc.), each contributing a portion of the total output current. This segmentation allows precise current control through individual cell activation while reducing the area compared to a single large current generator.
Solution Approach 2:
The circuit employs dynamic switching of current cells based on the desired output current level. Switches control the activation of individual current cells, allowing the circuit to adapt its configuration and activate only the necessary components, thereby reducing power consumption and effective area for different operating conditions.
2Measurement precision
If conventional transconductance circuits are used to generate precise output currents, then current precision is improved, but power consumption increases
Solution Approach 1:
The circuit dynamically switches between different current cells based on the required output current level. This allows the circuit to consume power only from the activated cells, rather than continuously powering all components, thereby reducing overall power consumption while maintaining precision.
Solution Approach 2:
Different current cells can be activated selectively based on local requirements. The circuit applies quality control locally by enabling only the necessary current cells for the current operating condition, reducing power consumption in inactive regions while maintaining precision in active regions.
3Power
If conventional transconductance circuits are used to drive high inductance loads, then load drive capability is improved, but noise increases
Solution Approach 1:
The circuit incorporates feedback mechanisms where the output current is monitored and used to control the switching of current cells. This feedback allows the circuit to maintain stable operation and reduce noise while driving high inductance loads by continuously adjusting the output based on actual conditions.
Solution Approach 2:
The patent introduces an intermediary control mechanism where switches and control logic mediate between the input voltage and the current cells. This intermediary layer allows for controlled activation of current cells, reducing noise generation while maintaining the ability to drive high inductance loads effectively.
4Adaptability or versatility
If multiple current cells are used to expand output current range, then adaptability is improved, but device complexity increases
Solution Approach 1:
The output current range is expanded by segmenting the total current into multiple discrete current cells. Each cell contributes a specific portion of the total current, allowing the circuit to achieve a wide current range through combinatorial activation of cells rather than using a single complex current generator.
Solution Approach 2:
Multiple current cells are merged in parallel to achieve the total output current. The switches control the combination of individual current cell outputs, allowing the circuit to achieve versatile current ranges by combining different subsets of cells, thereby managing complexity through modular combination rather than monolithic design.
Data Source
AI summary
Disclosed herein are transconductance circuits, as well as related methods and devices. In some embodiments, a transconductance circuit may include an amplifier having a first input coupled to a voltage input of the transconductance circuit, and a switch coupled between an output of the amplifier and a second input of the amplifier.