Bias Circuit Compensation for Amplifier Thermal History Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-power and high-frequency amplifiers experience characteristic changes due to thermal history, leading to irreversible changes in drain idle current and gain degradation over time, which affects their performance.
Innovation Solution
An amplifier circuit with a bias circuit that includes a second transistor on the same semiconductor chip, where the bias voltage adjusts based on the thermal history to compensate for changes in the first transistors' drain idle current, ensuring stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bias circuit with temperature compensation function is provided to compensate temperature change of idle current, then the amplifier can maintain stable operation at different temperatures, but the drain idle current still changes irreversibly due to thermal history effects
Solution Approach 1:
The bias circuit performs preliminary compensation by applying a pre-calculated bias voltage that anticipates the thermal history effect. The circuit is designed to counteract the irreversible drain idle current change before it degrades amplifier performance, based on the relationship between cumulative power consumption and threshold voltage shift.
Solution Approach 2:
The bias circuit dynamically adjusts the bias voltage parameter based on the thermal history of the amplifier. By monitoring cumulative power consumption and using it to modulate the bias voltage, the circuit compensates for threshold voltage shifts and maintains stable drain idle current despite thermal aging effects.
2Power
If the amplifier operates at high power for extended periods, then high power output is achieved, but irreversible changes in drain idle current and gain degradation occur due to thermal history
Solution Approach 1:
The bias circuit implements a feedback mechanism where cumulative power consumption is monitored and used to adjust the bias voltage. This feedback loop continuously compensates for thermal history effects, allowing the amplifier to maintain stable drain idle current and gain even during extended high-power operation by dynamically counteracting threshold voltage shifts.
Data Source
AI summary
An amplifier includes an amplifier circuit 10 having a characteristic changing in accordance with a thermal history, and a bias circuit 20 that includes an element subjected to a thermal history corresponding to the thermal history of the amplifier circuit, and supplies a bias voltage to the amplifier circuit. The bias voltage changes based on a characteristic of the element that changes in accordance with the thermal history of the element.