Receiver AGC Circuit with Stored Gain for Low-Power Drift Control
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Solution Overview
Problem
Conventional automatic gain control (AGC) circuits consume power continuously, making them unsuitable for power-constrained environments in modern integrated circuits and electronics, where thermal considerations and increasing I/O counts shrink power budgets.
Innovation Solution
Implementing a low-power AGC circuit with a gain control memory to store and maintain the desired amplification level, allowing the update loop to be disabled for power savings, and periodically re-enabled to compensate for drift, using digital or analog techniques to adjust the gain control value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the gain control loop operates continuously to maintain desired signal amplification, then the signal amplification accuracy is improved, but the power consumption increases
Solution Approach 1:
The patent implements periodic sampling of the amplified signal level at discrete time intervals, followed by periodic updates of the gain control value only when drift is detected. The gain control loop transitions from continuous operation to periodic operation, where the envelope detector, comparator, and filter circuit are activated at scheduled intervals rather than continuously, thereby reducing power consumption while maintaining adequate signal amplification accuracy through periodic correction of drift.
Solution Approach 2:
The patent extracts and separates the drift compensation function from the continuous gain control loop. By using a periodic sampling mechanism that detects drift only when it exceeds a threshold, the system removes the need for continuous monitoring and adjustment, extracting only the essential corrective action needed to maintain accuracy while eliminating unnecessary continuous operation that consumes power.
2Use of energy by moving object
If the update loop is disabled to save power, then power consumption is reduced, but the ability to compensate for drift is lost
Solution Approach 1:
The patent implements a self-monitoring mechanism where the periodic sampling system automatically detects when drift exceeds a predetermined threshold and triggers a gain control update only when needed. The system serves itself by autonomously determining when correction is necessary, eliminating the need for continuous external control while maintaining reliability through event-driven updates that respond to actual drift conditions.
Solution Approach 2:
The patent changes the operational parameters of the gain control loop from continuous to periodic by introducing a sampling interval parameter and a drift threshold parameter. These parameter changes allow the system to operate in a low-power state most of the time while periodically transitioning to an active state when drift detection indicates correction is needed, thus balancing power consumption with drift compensation capability.
Data Source
AI summary
An integrated circuit receiver includes a first channel comprising an amplifier responsive to a first gain control value in a first mode to receive an input signal and generate a first amplified signal having a transition rate. Detection circuitry in the first channel detects transitions in the first amplified signal in accordance with a detected transition rate. The detected transition rate is based on the first gain control value. Gain control logic adjusts the first gain control value based on a desired detected transition rate. The gain control logic generates a second gain control value for use during a second mode. The second gain control value being based on the first gain control value.