Multi-Transistor Analog Switch for Open-State Isolation
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Solution Overview
Problem
Analog switches allow current to pass through when open, which can corrupt sampling measurements in systems that include analog-to-digital converters, due to inadequate isolation between input and output.
Innovation Solution
A switch configuration using multiple transistors to provide multiple layers of electrical isolation, ensuring that current does not bleed through when the switch is open, even for signals above or below reference voltages, by controlling the transistors with clock signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an analog switch is used to electrically connect or isolate two sides of a circuit, then the switch can control signal transmission, but current may still pass through the switch when open due to inadequate isolation
Solution Approach 1:
The analog switch is divided into two separate switches: a first analog switch for signals above the ground reference voltage and a second analog switch for signals below the ground reference voltage. This segmentation allows each switch to be optimized for its specific voltage range, preventing current leakage that would occur in a single switch design when handling signals of opposite polarities.
Solution Approach 2:
A ground reference voltage is introduced as an intermediary between the input and output sides of the switch configuration. This ground reference acts as a mediator that separates the positive and negative signal paths, allowing independent control of isolation for signals above and below ground, thereby eliminating the current leakage problem.
2Adaptability or versatility
If a single analog switch is used to handle signals above and below reference voltage, then device complexity is minimized, but isolation performance deteriorates for signals of opposite polarities
Solution Approach 1:
The signal handling range is segmented into two separate domains: signals above ground reference voltage handled by the first analog switch, and signals below ground reference voltage handled by the second analog switch. This segmentation enables each switch to maintain optimal isolation performance for its designated signal range while collectively handling the full voltage spectrum.
Solution Approach 2:
The switch configuration achieves multi-functionality by combining two analog switches that together handle both positive and negative signals relative to ground. Each switch is specialized for its voltage range, but the combined system provides universal signal handling capability across the entire voltage spectrum with maintained isolation performance.
3Device complexity
If current leakage through the open switch is allowed, then device simplicity is maintained, but measurement precision is corrupted in sampling systems
Solution Approach 1:
The measurement system is protected by segmenting the signal path into two isolated paths controlled by separate analog switches. This segmentation prevents current leakage from corrupting sampling measurements by ensuring that when one switch is open, its corresponding signal path is fully isolated, maintaining measurement precision without excessive complexity.
Data Source
AI summary
A switch is provided. The circuit includes a plurality of transistors configured to electrically isolate the input of the switch from the output of the switch. In one embodiment, for example, the plurality of transistors may be configured to provide at least one path between the input and the output of the switch, and to provide at least three layers of electrical isolation between the input and the output of the switch when the switch is open.