VGA Read/Write Circuit for AGC and Manual Gain Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing amplification circuits with variable gain amplifiers and automatic gain control loops do not efficiently allow the output signal of the AGC loop to be provided to peripheral systems, limiting the ability to read and control the gain in both automatic and manual gain control modes.
Innovation Solution
Incorporating a read/write circuit that allows the contact to function as both an input and output, with a switching mechanism to switch between write-mode and read-mode paths based on the selected mode, ensuring the output signal of the AGC loop can be read without affecting the gain setting in AGC mode and allowing manual gain control in MGC mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the contact is used as an input pin for manual gain control, then the peripheral system can write the desired gain value, but the output signal of the AGC loop cannot be read out by the peripheral system when AGC mode is activated
Solution Approach 1:
The contact is designed to serve dual purposes: as an input pin for manual gain control in MGC mode and as an output pin for reading the AGC loop signal in AGC mode. This multi-functionality is achieved through a switching mechanism that routes signals appropriately based on the selected mode, eliminating the need for separate input and output contacts.
Solution Approach 2:
The switching mechanism dynamically changes the function of the contact based on the operating mode. When MGC mode is selected, the contact functions as an input; when AGC mode is selected, the same contact functions as an output. This dynamic reconfiguration allows the system to adapt the contact's role according to operational requirements.
2Adaptability or versatility
If the output of the peak detector is always available through the buffer on the PKD pin, then the peripheral system can read the signal, but the same contact cannot be used for both writing gain values and reading output signals
Solution Approach 1:
The contact is designed to serve dual purposes: as an input pin for manual gain control in MGC mode and as an output pin for reading the AGC loop signal in AGC mode. This multi-functionality is achieved through a switching mechanism that routes signals appropriately based on the selected mode, eliminating the need for separate input and output contacts.
Solution Approach 2:
The switching mechanism acts as an intermediary between the contact and the internal circuitry, directing the signal flow based on the selected mode. It mediates between the conflicting requirements of input and output functionality by selectively connecting the contact to either the manual gain control input or the AGC loop output buffer.
Data Source
Figure 1(a)~1(b)
Figure 2
Figure 3
AI summary
The invention relates to an amplification circuit (100), comprising: a VGA (2), an AGC loop (10) for automatically controlling the gain of the VGA (2), a switching circuit (14) for switching between an AGC mode, in which the gain of the VGA (2) is automatically controlled by an output signal of the AGC loop (10) and a manual gain control, MGC, mode, in which the gain of the VGA (2) can be manually controlled by an input signal, and a read/write circuit (30) with a contact (31) for connection to a peripheral system, wherein the read/write circuit (30) is configured, in the MGC mode, to provide the input signal from the contact (31) via a write-mode path (32) to the VGA (2), and, in the AGC mode, to provide the output signal of the AGC loop (10) via a read-mode path (33) on the contact (31).