Stacked Transconducting Cell Amplifier for Current-Mode Power Combining

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Solution Overview

Problem

Conventional high-voltage signal amplifiers face limitations in output power and efficiency due to device stacking approaches, particularly in high-frequency millimeter-wave bands, where voltage handling is reduced, and layout size and reliability concerns are significant.

Innovation Solution

The design employs stacked transconducting cells in current mode combining, with a cascode connection for DC supply current and cascade or parallel connections for RF input and output currents, using a single-input single-output matching network to reduce gate/base resistive losses and simplify layout, allowing for higher output power and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If device stacking is used to increase output power, then output power is improved, but layout size increases and reliability concerns arise

Engineering Contradiction:

Improveoutput powerVSAvoidreliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The amplifier is divided into multiple transconducting cells stacked in series, with each cell handling a portion of the total voltage. This segmentation allows the system to achieve high output power while maintaining reliability by distributing the voltage stress across multiple smaller units rather than concentrating it in a single device.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple transconducting cells are combined in a stacked configuration where their individual outputs are summed. The patent merges the current outputs of stacked cells through current-mode combining, achieving higher output power while maintaining compact layout and improved reliability compared to conventional voltage-mode combining.

Inventive Principle:

Principle #5Merging (Combining)

2Power

If device stacking is used to increase output power, then output power is improved, but layout size increases

Engineering Contradiction:

Improveoutput powerVSAvoidlayout size

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The patent transitions from planar parallel combining to vertical stacking in the third dimension. By stacking transconducting cells in series and using current-mode combining, the design achieves power multiplication without proportionally increasing layout area, as the stacked configuration utilizes vertical space more efficiently.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent replaces conventional voltage-mode power combining mechanisms with current-mode combining. This substitution eliminates the need for large passive combining networks and transformers, significantly reducing layout size while maintaining high output power capability through direct current summation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Power

If voltage mode combining is used, then output power is improved, but reliability concerns increase

Engineering Contradiction:

Improveoutput powerVSAvoidreliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent substitutes voltage-mode combining with current-mode combining throughout the signal path. By maintaining current-mode operation in the combining network, the design achieves high output power while improving reliability through reduced sensitivity to impedance variations and eliminated voltage stress on combining network components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Speed

If smaller device feature sizes are used to increase frequency performance, then frequency performance is improved, but voltage handling is reduced

Engineering Contradiction:

Improvefrequency performanceVSAvoidvoltage handling

Core Design Contradiction:

SpeedVSStress or pressure

Solution Approach 1:

The total supply voltage is segmented across multiple stacked transconducting cells, with each cell experiencing only a fraction of the total voltage. This allows the use of smaller feature size devices optimized for high frequency operation while maintaining adequate voltage handling capability through the stacked configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the operating parameters by transitioning from single-device high-voltage operation to multi-device stacked operation. Each device in the stack operates at lower voltage but higher frequency, achieving overall system performance that combines both high frequency capability and adequate voltage handling through parameter optimization at the device level.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4120564A1Amplifier with stacked transconducting cells in parallel and/or cascade current mode combining

Publication Date: 2023.01.18 THE BOEING CO

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AI summary

An amplifier with stacked transconducting cells in parallel and/or cascade "current mode" combining is disclosed herein. In one or more examples, 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 examples, 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).