Differential Amplifier Gain Control Using Cross-Over Current Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In differential amplifier systems, process, voltage, and temperature variations can cause cross-over currents due to imprecise phase control of input signals, leading to power loss and inaccurate gain control in feedback loops.
Innovation Solution
An amplifier system comprising a main amplifier, a cross-over current detector, and a controller that detects cross-over currents and uses this information to generate control signals for precise gain control, improving the accuracy of power amplification and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If differential power transistors are used to amplify input signals, then signal amplification capability is improved, but cross-over current is generated causing power loss
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the cross-over current generated by the differential power transistors and adjusts the bias voltage accordingly. This feedback loop reduces the cross-over current while maintaining the signal amplification capability of the differential pair, thereby resolving the contradiction between power amplification and energy loss.
Solution Approach 2:
The patent dynamically changes the bias voltage parameter applied to the differential power transistors based on the detected cross-over current level. By adjusting this electrical parameter, the system optimizes the operating point of the transistors to minimize cross-over current while preserving the necessary amplification function, thus resolving the energy loss issue without sacrificing signal amplification capability.
2Measurement precision
If feedback loop is applied to control amplifier gain, then gain control capability is improved, but cross-over current affects accuracy of gain control
Solution Approach 1:
The patent enhances the feedback loop by incorporating cross-over current detection and compensation. The controller uses feedback from both the output signal and the detected cross-over current to adjust the bias voltage, ensuring that the gain control remains accurate despite the presence of cross-over current. This dual-feedback mechanism resolves the contradiction by maintaining gain control precision while accounting for cross-over current effects.
Solution Approach 2:
The patent introduces the cross-over current detector as an intermediary component between the amplifier and the controller. This intermediary device provides accurate measurement of the cross-over current, enabling the controller to make precise adjustments to the bias voltage. By using this intermediary measurement, the system maintains reliable gain control accuracy despite the interfering cross-over current.
Data Source
AI summary
An amplifier system includes a main amplifier, a cross-over current detector and a controller. The main amplifier includes at least a first driving transistor and a second driving transistor serving as a differential pair, wherein the first driving transistor and the second driving transistor are arranged to receive a first input signal and a second input signal, respectively. The cross-over current detector is coupled to the main amplifier, and is arranged for detecting a cross-over current of the main amplifier, wherein the cross-over current of the main amplifier is an overlapped current from the differential pair. The controller is coupled to the main amplifier and the cross-over current detector, and is arranged for generating a control signal to control a gain of the main amplifier according to an output of the main amplifier and the cross-over current of the main amplifier.