Power Amplifier Bias Precharge for Startup Delay Reduction
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Solution Overview
Problem
Power amplifiers experience a delay phenomenon due to unsynchronized bias and input signals, leading to inadequate amplification and adverse effects on power calibration, especially in low power modes.
Innovation Solution
A power amplifier design that includes a standby circuit with a resistor connected between the source and drain of a transistor in the bias circuit, allowing a predetermined voltage to be applied to the amplification unit before the input signal, ensuring synchronized bias and input signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the bias circuit generates the bias signal after the input signal is applied, then the circuit operation is simplified, but a delay phenomenon occurs in signal amplification
Solution Approach 1:
The bias circuit is designed to generate and apply the bias signal to the amplification device before the input signal is applied. This preliminary action ensures that the amplification device is already in the active state when the input signal arrives, eliminating the delay phenomenon while maintaining simplified circuit operation.
2Adaptability or versatility
If the bias signal is not synchronized with the input signal, then the circuit design is more flexible, but the input signal cannot be amplified properly
Solution Approach 1:
The bias circuit incorporates a feedback mechanism that detects the input signal and automatically adjusts the timing of the bias signal generation. This feedback ensures that the bias signal is always synchronized with the input signal, guaranteeing proper signal amplification while maintaining circuit design flexibility through automatic adaptation.
3Device complexity
If the bias circuit operates independently without synchronization, then the circuit modularity is improved, but power calibration is adversely affected
Solution Approach 1:
The bias circuit is designed with multi-functionality, serving both as an independent modular unit and as a synchronized component. It includes a universal timing mechanism that can operate independently for modularity while also synchronizing with the input signal for accurate power calibration, achieving both circuit modularity and measurement precision.
Data Source
AI summary
There is provided a power amplifier. The power amplifier includes an amplification unit including at least one amplification device; a power generation unit generating an input signal supplied to the amplification unit; and a bias circuit unit controlling bias of the at least one amplification device according to the input signal, wherein the bias circuit unit supplies a predetermined bias voltage to the amplification unit before the input signal is applied to the amplification unit. According to the embodiments of the present invention, a delay phenomenon occurring at an initial driving time or a low power mode may be significantly reduced by supplying a predetermined bias signal to an amplification unit in a standby circuit before the bias circuit unit of the power amplifier normally outputs the bias signal to the amplification unit.