Transmit Receive Switch With Clamp Circuit For Ultrasound Receiver Protection
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Solution Overview
Problem
Existing ultrasound systems face challenges in protecting receivers from high voltage ultrasound signals during transmit modes while ensuring minimal switching artifacts and efficient echo signal reception during receive modes.
Innovation Solution
A transmit/receive switch utilizing metal-oxide-semiconductor field effect transistors (MOSFETs) is employed, coupled with a clamp circuit to block high voltage signals during transmission and allow echo signals to pass through during reception, minimizing noise contribution and switching artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transmit/receive switch is used to protect the receiver from high voltage transmitted signals, then the receiver is protected from damage, but switching artifacts and noise are introduced during signal transmission and reception
Solution Approach 1:
The clamp circuit is activated in advance during the transmit period to clamp any transmitted signal that leaks through the T/R switch to ground potential before it can reach and damage the receiver. This preliminary protective action prevents the harmful effect while minimizing switching artifacts during the critical receive period.
Solution Approach 2:
The clamp circuit acts as an intermediary protective element between the T/R switch and the receiver. It provides an additional layer of protection by clamping residual high voltage signals to ground, thereby preventing damage to the receiver while maintaining signal integrity during reception.
2Reliability
If the transmit/receive switch blocks high voltage signals during transmit mode, then the receiver is protected, but the switching transition introduces noise and artifacts
Solution Approach 1:
The clamp circuit is activated during the transmit period to prepare the receiver input path by clamping any potential high voltage signals to ground. This preliminary action ensures that when the T/R switch transitions to receive mode, the receiver is already protected and ready to receive weak echo signals without interference from residual transmit signals or switching artifacts.
Solution Approach 2:
The clamp circuit converts the potentially harmful high voltage transmitted signal into a beneficial protective mechanism by clamping it to ground. This transforms the harmful high voltage that could damage the receiver into a controlled reference potential, thereby protecting the receiver while minimizing noise and switching artifacts during the receive period.
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
Effectively protects the receiver from high voltage ultrasound signals during transmission and enables efficient echo signal detection during reception, maintaining signal quality and reducing switching artifacts.
Implementation Method 1
one or more field effect transistors (FETs) coupled between the first node and a second node, wherein the one or more FETs are configured to be turned on during a receive period to couple the first node and the second node such that a second signal is passed from the first node to the second node during the receive period, and to be turned off during the transmit period to substantially block the first signal from the second node
Implementation Method 2
The transmit/receive switch also includes a clamp circuit coupled to the second node, wherein the clamp circuit is configured to protect the second node from excess voltages
Data Source
AI summary
Apparatus and methods are disclosed, such as those involving an electronic device. One such apparatus includes a transmitter; a receiver; and a transmit/receive switch configured to electrically block the receiver from the transmitter during a transmit period. The transmit/receive switch includes one or more MOSFETs coupled between an input node and an output node, the input node being electrically coupled to the transmitter, the output node being electrically coupled to the receiver. The one or more MOSFETs are configured to be off during the transmit period. The transmit/receive switch further includes a clamp circuit configured to couple the output node to ground during the transmit period. This configuration effectively protects the receiver while minimizing switching artifacts.