Power Amplifier Gain Latching to Reduce RF Spurs
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Solution Overview
Problem
Existing over-current protection techniques for power amplifiers in wireless communication devices cause interference due to signal chopping, leading to spurs in the RF band.
Innovation Solution
Implementing an open-loop over-current protection scheme that adjusts amplification gain to a stable level until a gain event occurs, using a latch to maintain the adjusted gain until a new packet is processed, thereby reducing spurs and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing over-current protection techniques are used, then over-current conditions are protected against, but signal chopping causes interference and spurs in the RF band
Solution Approach 1:
The latch circuit preemptively latches the gain control value before over-current damage occurs, and the open-loop maintenance of adjusted gain prevents signal chopping during the over-current condition, thereby preventing RF interference and spurs before they can be generated
Solution Approach 2:
The over-current detection circuit provides feedback to the latch circuit, which then adjusts and maintains the gain control value to prevent over-current conditions while avoiding the signal chopping that would cause RF interference
2Reliability
If amplification gain is adjusted during over-current condition, then over-current protection is achieved, but gain stability may be compromised until gain event occurs
Solution Approach 1:
The latch circuit captures and holds the adjusted gain control value in advance, maintaining it stable until a gain event occurs, thereby preventing gain fluctuations while still providing over-current protection
Solution Approach 2:
The system dynamically adjusts the gain control value when over-current conditions are detected, then maintains that dynamic adjustment stable through the latch circuit until a gain event triggers a new adjustment, balancing adaptability with stability
Data Source
AI summary
Certain aspects of the present disclosure generally relate to electronic circuits and, more particularly, to techniques and apparatus for signal amplification. One example method for signal amplification generally includes detecting an over-current condition associated with an amplifier and adjusting an amplification gain to an adjusted gain level for an input signal based on the over-current condition. The amplification gain may be maintained at the adjusted gain level until occurrence of an amplifier gain event. The method may also include amplifying, via the amplifier, the input signal based on the adjusted amplification gain.