Multi-Cell Amplifier Gain Control for Wide-Range Precision
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Solution Overview
Problem
Existing amplifier circuits face challenges in accurately controlling gain over a wide range, particularly in radio transmitters, where precise power management is crucial to comply with regulatory limits and optimize battery life, especially when using limited energy resources.
Innovation Solution
The amplifier circuit portion is designed with multiple cells operating in controllable, fixed, and disabled modes, allowing for tailored gain profiles and improved precision through configuration signals, enabling precise control of gain using a lower-resolution gain control signal by setting minimum and maximum gain configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-resolution gain control signal is used to control the gain over a wide range, then the precision of gain control is improved, but the complexity of the control system increases
Solution Approach 1:
The amplifier is divided into multiple amplifier cells, each contributing a fixed gain portion. The total gain is segmented into fixed portions (from individual cells) and a variable portion (from the summing combiner), allowing coarse gain adjustment through cell selection and fine adjustment through the variable gain control signal.
Solution Approach 2:
The invention changes the parameter of gain control by transitioning from a single high-resolution variable gain control to a hybrid approach where some gain is fixed (discrete steps through cell inclusion/exclusion) and the remainder is variable (continuous or fine-stepped control). This reduces the resolution requirement for the variable gain control signal.
2Adaptability or versatility
If the gain range of the amplifier is increased to cover wider transmission power outputs, then the versatility of the amplifier is improved, but the precision of gain control deteriorates
Solution Approach 1:
The total gain range is segmented into multiple fixed gain contributions from individual amplifier cells. Each cell provides a predetermined gain amount, and by selectively enabling different combinations of cells, the amplifier can cover a wide gain range while maintaining precise control through the remaining variable gain portion.
Solution Approach 2:
The invention adds a dimensional aspect to gain control by introducing multiple amplifier cells that can be independently controlled. This creates a two-dimensional gain control space: one dimension is the fixed gain from selected cells, and the other is the variable gain from the controlled amplifier portion, together providing wide range with high precision.
3Measurement precision
If multiple amplifier cells are used to provide fixed gain portions, then the precision of gain control is improved through reduced control signal resolution requirements, but the device complexity increases
Solution Approach 1:
Multiple amplifier cells are designed with identical or similar circuit topologies, making them universal building blocks. Each cell can be independently controlled to provide its fixed gain contribution, and they all feed into the same summing combiner. This modular universality allows precise gain control through simple binary selection of identical units, minimizing control complexity despite increased device complexity.
Data Source
AI summary
An amplifier circuit portion is proved. The amplifier circuit is arranged to amplify an input signal with a gain based on a gain control signal. The amplifier circuit portion comprises a plurality of amplifier cells having a common input for receiving the input signal and a common output for providing an amplified version of the input signal. At least one of the amplifier cells is operable in: a controllable gain mode in which the amplifier cell provides an amplification gain to the input signal based on the gain control signal; and a fixed gain mode in which the amplifier cell provides a fixed, non-zero amplification gain to the input signal.