Front-End Sampling Circuit With Auxiliary Path for Faster ADC Tracking
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Solution Overview
Problem
Analog to digital converters face challenges in tracking high-frequency input signals within limited sampling periods, leading to signal distortion and lower resolution due to the long processing times required by existing sampling circuits.
Innovation Solution
A front-end sampling circuit employing a global switch, local switches, and auxiliary switches, where the auxiliary switches provide additional signal paths by turning on earlier or at the same time as the global switch, allowing for improved tracking speed without affecting the sampling operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the sampling circuit uses the existing approach with a single switch, then the circuit structure remains simple, but the processing time becomes too long to track high-frequency input signals within the limited sampling period
Solution Approach 1:
The sampling circuit is divided into two parallel paths: a main sampling path with a global switch for normal operation, and an auxiliary tracking path with an auxiliary switch for high-frequency signal tracking. This segmentation allows each path to be optimized for its specific function, resolving the contradiction between tracking speed and circuit complexity.
Solution Approach 2:
The auxiliary switch is turned on earlier than the global switch to preliminarily establish the tracking path before the main sampling operation begins. This preliminary action allows the storage circuit to start tracking the high-frequency input signal earlier, improving tracking speed without significantly increasing overall circuit complexity.
2Measurement precision
If the sampling circuit extends the processing time to accurately track the input signal, then the signal distortion is reduced, but the sampling period becomes insufficient for high-frequency signals
Solution Approach 1:
The auxiliary switch maintains a continuous tracking connection during the sampling period, allowing the storage circuit to continuously track the high-frequency input signal without interruption. This continuous useful action ensures signal accuracy is maintained while utilizing the full sampling period efficiently.
Solution Approach 2:
By turning on the auxiliary switch earlier to establish the tracking path before the main sampling operation, the system gains additional tracking time within the same sampling period. This preliminary action resolves the time loss by effectively extending the useful tracking duration without extending the overall sampling period.
3Speed
If the auxiliary switch turns off later than the global switch, then the tracking continues longer, but signal distortion occurs due to interference with the sampling operation
Solution Approach 1:
The auxiliary switch is designed to turn off earlier than or at the same time as the global switch to preemptively prevent potential interference with the sampling operation. This preliminary anti-action ensures signal integrity by eliminating the possibility of tracking path interference before it can occur, while still maintaining adequate tracking speed through the extended turn-on duration.
Data Source
AI summary
A front-end sampling circuit includes a global switch, a local switch, and an auxiliary switch. The global switch is configured to be selectively turned on according to a first control signal, in order to transmit an input signal. The local switch is configured to be selectively turned on according to a second control signal, in order to transmit the input signal from the global switch to a node, wherein a storage circuit is coupled to the node to store the input signal. The auxiliary switch is configured to be selectively turned on according to a third control signal, in order to transmit the input signal to the node, in which a turn-off time point of the auxiliary switch is set to be the same or earlier than a turn-off time point of the global switch.