Differential Transmission Circuit With Reception-Mode Drive Cutoff
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional differential transmission circuits face challenges in maintaining a high clamp level during reception periods without narrowing the dynamic range of the output, particularly due to voltage drops and excessive current flow caused by common mode noise.
Innovation Solution
The proposed differential transmission circuit employs MOSFET output transistors, a signal generation unit, and a cutoff unit that cuts off the drive signal supply path during reception, along with short-circuit transistors and resistors to manage common mode noise, ensuring high impedance and delayed transistor activation, thus expanding the clamp level without voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive signal supply path is not cut off during reception period, then the output transistors can respond quickly to signals, but common mode noise causes excessive current flow and voltage drops reducing clamp level
Solution Approach 1:
The cutoff unit proactively disconnects the drive signal supply path before reception begins, preventing common mode noise from causing excessive current flow and voltage drops. This preliminary protective action maintains high clamp level during reception by eliminating the vulnerability to noise interference in advance.
2Object-affected harmful factors
If the drive signal supply path is cut off during reception period, then common mode noise impact is reduced, but the transition to transmission mode may be delayed
Solution Approach 1:
The cutoff unit dynamically switches between connected and disconnected states based on communication mode. During reception, it disconnects to protect against common mode noise; during transmission, it connects to enable fast signal response. This dynamic adaptation optimizes both noise immunity and switching speed by matching the circuit state to operational requirements.
3Reliability
If short-circuit transistors are connected between gates and drains of output transistors, then clamp level is improved during reception, but circuit complexity increases
Solution Approach 1:
The short-circuit transistors serve multiple functions: they act as protection elements during reception to maintain high clamp level, and as switching elements during mode transitions. By integrating these transistors into the existing output transistor structure, the patent achieves enhanced noise immunity without proportionally increasing overall circuit complexity.
Data Source
AI summary
A differential transmission circuit for a communication device performs bidirectional communication via a differential transmission line. The differential transmission circuit include: output transistors that are turned on and off according to a drive signal during a transmission period; a signal generation unit that generates and outputs the drive signal; short-circuit transistors connected between gates and drains of the output transistors; and a cut off unit that cuts off a supply path of the drive signal between the signal generation unit and the gates of the output transistors. The cut off unit cuts off the supply path of the drive signal during a reception period in which a reception operation is performed by the communication device.