Transistor Switching Circuit With Voltage Follower Signal Isolation
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Solution Overview
Problem
Existing transistor switching circuits experience signal deviation due to voltage drops across drain terminals caused by control currents flowing through transistors.
Innovation Solution
A transistor switching circuit is designed with a voltage follower configuration, where the gate and source of transistors M1 and M2 are connected to separate nodes, and a resistive device is placed between the gate of transistor M3 and its source, preventing control currents from flowing through M1 and M2, thus eliminating voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resistor is connected between the gate and source of transistors to generate gate-source voltage, then the transistor switching function is achieved, but voltage drop occurs across drain terminals causing signal deviation
Solution Approach 1:
A voltage follower circuit is introduced as an intermediary between the current source and the transistor gates. The voltage follower converts the current signal from the current source into a voltage signal that drives the transistor gates, eliminating the need for resistors connected to transistor sources and preventing voltage drops across drain terminals.
Solution Approach 2:
The circuit is divided into separate functional modules: a current source for generating control current, a voltage follower for current-to-voltage conversion, and transistor switches for signal routing. This segmentation allows the control current to flow through the voltage follower rather than through the transistor switches, eliminating voltage drops.
2Extent of automation
If control current flows through transistors M1 and M2 to enable switching, then transistor activation is achieved, but voltage drop across drain terminals causes signal error
Solution Approach 1:
The voltage follower acts as a mediator that decouples the control current path from the signal path. The control current flows through the voltage follower's transistor M3 instead of through the signal transistors M1 and M2, eliminating voltage drops that cause signal errors while maintaining full transistor activation capability.
3Ease of manufacture
If resistor R is used to generate gate-source voltage from current source, then transistor control is enabled, but the structure causes voltage drop and signal deviation
Solution Approach 1:
The passive resistor-based voltage generation mechanism is replaced with an active voltage follower circuit that uses transistor M3 and a second current source. This substitution maintains ease of manufacture using standard semiconductor components while eliminating the voltage drop problem inherent in resistor-based designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces signal errors by preventing voltage drops across the drain terminals, enhancing the accuracy and stability of signal transmission in semiconductor integrated circuits.
Implementation Method 1
a voltage follower including a transistor M3 and a second current source, wherein the gate of the transistor M3 is connected to the second node S1, and the source of the transistor M3 is connected to the second current source
Implementation Method 2
The resistive device is connected between the first node G and the source of the transistor M3
Data Source
AI summary
A transistor switching circuit and an integrated circuit thereof are provided. The transistor switching circuit includes: at least two transistors M1 and M2, and a voltage follower. The gate of the transistor M1 and the gate of the transistor M2 are connected to a first node G, the first node G is connected to a first current source, and the source of the transistor M1 and the source of the transistor M2 are connected to a second node S1. The voltage follower includes a transistor M3 and a second current source. The gate of the transistor M3 is connected to the second node S1, and the source of the transistor M3 is connected to the second current source. One end of a resistive device is connected to the source of the transistor M3, and another end of the resistive device is connected to the first node G.