Current-Mode Stacked Transconducting Amplifier for High-Voltage RF Power
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Solution Overview
Problem
Conventional high-voltage signal amplifiers face limitations in output power and efficiency due to device stacking approaches, which result in reliability concerns and large layout sizes, especially when using voltage mode combining techniques.
Innovation Solution
The design employs stacked transconducting cells in current mode combining, where transconducting cells are connected in cascode for DC supply current and in cascade or parallel for RF input and output signals, utilizing single-input single-output matching networks to reduce gate/base resistive losses and simplify the layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional voltage mode combining techniques are used with stacked devices, then output power can be increased, but layout size becomes large and reliability concerns arise
Solution Approach 1:
The patent merges multiple transconducting cells into a stacked configuration where they share a common DC supply current path. The cells are combined such that their AC RF output currents are summed at a common output node, eliminating the need for separate combining networks for each cell and reducing overall layout size while maintaining high output power capability
Solution Approach 2:
The amplifier is segmented into multiple transconducting cells that are stacked in series for DC current sharing. Each cell processes a portion of the total output power requirement, and the segmented cells are connected such that their outputs are combined at a common node, achieving power scaling without proportional increase in layout area
2Power
If conventional voltage mode combining techniques are used with stacked devices, then output power can be increased, but reliability concerns arise
Solution Approach 1:
The patent merges multiple transconducting cells into a stacked configuration where they share a common DC supply current path. The cells are combined such that their AC RF output currents are summed at a common output node, eliminating the need for separate combining networks for each cell and reducing overall layout size while maintaining high output power capability
Solution Approach 2:
The patent introduces a common output node as an intermediary that collects AC RF output currents from all stacked transconducting cells. This intermediary node serves as a reliable aggregation point that simplifies the combining process and reduces the complexity and potential failure points associated with conventional voltage mode combining techniques
3Power
If device stacking is used to increase output power, then higher power is achieved, but gate/base resistive losses increase
Solution Approach 1:
The patent replaces the conventional voltage mode combining mechanism with a current mode combining approach. Instead of combining voltages through resistive networks that incur gate/base losses, the invention combines AC RF output currents directly at a common node, substituting the voltage combining mechanism with a current summing mechanism that avoids the associated resistive losses
4Power
If conventional stacked device approaches are used, then higher output power is achieved, but layout size increases
Solution Approach 1:
The patent merges multiple transconducting cells into a stacked configuration where they share a common DC supply current path. The cells are combined such that their AC RF output currents are summed at a common output node, eliminating the need for separate combining networks for each cell and reducing overall layout size while maintaining high output power capability
Solution Approach 2:
The common output node serves multiple functions: it acts as the DC current return path for all stacked cells, the AC RF output current summing point, and the single connection point to the output matching network. This multi-functionality reduces the number of separate components and connections needed, simplifying the overall layout
Data Source
AI summary
An amplifier with stacked transconducting cells in parallel and/or cascade “current mode” combining is disclosed herein. In one or more embodiments, a method for operation of a high-voltage signal amplifier comprises inputting, into each transconducting cell of a plurality of transconducting cells, a direct current (DC) supply current (Idc), an alternating current (AC) radio frequency (RF) input current (IRF_IN), and an RF input signal (RFIN). The method further comprises outputting, by each of the transconducting cells of the plurality of transconducting cells, the DC supply current (Idc) and an AC RF output current (IRF_OUT). In one or more embodiments, the transconducting cells are connected together in cascode for the DC supply current (Idc), are connected together in parallel (or in cascade) for the RF input signal (RFIN), and are connected together in parallel (or in cascade) for the AC RF output currents (IRF_OUT).