ASK Amplifier Bias and Enable Control for Smoother Power Transitions
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Solution Overview
Problem
In amplitude-shift keying (ASK) transmitters using switching power amplifiers, it is challenging to smooth the rising and falling of output power to suppress spurious wave radiation due to the rough control of bias voltage and the number of transistors, leading to increased radiation of unwanted frequencies.
Innovation Solution
An amplifier circuitry that includes a control circuitry to manage an enable signal and a bias signal, allowing for the selective activation of amplifier circuitries and adjustment of bias voltage to control the amplification factor, thereby smoothing the output power transitions and reducing spurious wave radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If switching power amplifier is used for ASK transmitter, then power efficiency is improved, but spurious wave radiation increases due to rough control of bias voltage and number of transistors
Solution Approach 1:
The patent divides the control of the switching power amplifier into two independent control signals: a first control signal for adjusting the bias voltage and a second control signal for adjusting the number of parallel-connected transistors. This segmentation allows independent optimization of each control parameter to achieve smooth output power transitions while maintaining high efficiency.
Solution Approach 2:
The patent implements dynamic control of both bias voltage and transistor count based on real-time signal conditions. The control circuitry continuously adjusts these parameters to maintain optimal operation, enabling smooth rising and falling of output power to suppress spurious wave radiation while preserving the efficiency benefits of switching operation.
2Power
If bias voltage control and transistor number control are used, then power amplification is achieved, but control precision deteriorates when numerical values are small or large due to transistor characteristics
Solution Approach 1:
The patent introduces control circuitry as an intermediary between the input signal and the power amplifier. This intermediary processes the input signal to generate optimized control signals that account for transistor characteristics, thereby compensating for control precision deterioration at extreme numerical values and maintaining accurate power amplification across the full operating range.
Data Source
AI summary
An amplifier includes a first circuitry, a second circuitry, and a plurality of amplifier circuitries. The first circuitry controls an enable signal. The second circuitry controls a bias signal. Circuitries which output signals are decided from among the plurality of circuitries based on the enable signal, and each of the circuitries which output the signals amplifies an input signal with a gain corresponding to the bias signal.