Power Amplifier Switch Sequencing to Suppress Gain Fluctuation
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Solution Overview
Problem
Conventional power amplifier circuits experience gain fluctuations due to mode switching, leading to potential communication errors.
Innovation Solution
A power amplifier circuit with a two-stage configuration, utilizing a first and second switch circuit to manage conduction and non-conduction between different nodes and the output terminal, allowing for controlled mode switching to suppress gain fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bypass switching circuit is used to switch operation mode according to output power magnitude, then power amplifier circuit can operate in different power modes, but gain fluctuation occurs during mode switching causing communication errors
Solution Approach 1:
The patent applies preliminary action by controlling the timing of switch transitions. Before switching from LPM to HPM mode, the first switch is turned off first, and the second switch is turned on after a predetermined time has elapsed. This preliminary sequencing prevents gain fluctuation and communication errors during mode transitions.
2Power
If high frequency signal path is switched using bypass switching circuit, then power output can be adjusted, but signal path may be cut off depending on switching timing resulting in gain drop
Solution Approach 1:
The patent ensures signal continuity by performing preliminary switching actions in a specific sequence. When transitioning from LPM to HPM, the first switch is turned off before the second switch is turned on, preventing any interruption in the high frequency signal path and avoiding gain drops.
3Power
If switching from low power mode to high power mode, then output power increases, but overshoot occurs and gain stabilization time increases
Solution Approach 1:
The patent reduces gain stabilization time by implementing preliminary controlled switching. A predetermined time interval is introduced between turning off the first switch and turning on the second switch during mode transitions, which prevents overshoot and accelerates gain stabilization while maintaining the required output power level.
Data Source
AI summary
A power amplifier circuit includes: a first switch circuit that switches conduction and non-conduction between a node between the drive stage amplifier and the power stage amplifier and an output terminal, and a second switch circuit that switches conduction and non-conduction between the power stage amplifier and the output terminal. The power amplifier circuit has a first mode in which the first switch circuit is made conductive and the second switch circuit is made non-conductive, and a second mode in which the first switch circuit is made non-conductive and the second switch circuit is made conductive. The power amplifier circuit makes, when shifting from the first mode to the second mode, the first switch circuit non-conductive after making the second switch circuit conductive, and makes, when shifting from the second mode to the first mode, the second switch circuit non-conductive after making the first switch circuit conductive.