Embedded-Attenuator SPDT Switches for Low-Loss RF Signal Paths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
SPDT switches in RF applications experience higher insertion loss and occupy a large area due to their design, particularly with the inclusion of inductors and resistors in the transmitter and receiver switches.
Innovation Solution
Incorporating embedded attenuators within the SPDT switch, utilizing series and shunt switching elements connected in parallel with inductors, allowing for selective control of attenuation levels by adjusting the states of these elements to minimize insertion loss and reduce switch area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an SPDT switch is used to provide fast switching between two outputs in RF applications, then switching speed is improved, but insertion loss increases
Solution Approach 1:
The patent combines the SPDT switch functionality with attenuator functionality into a single integrated circuit. The attenuator circuit includes series switching elements and shunt switching elements that are directly connected to the common input node of the SPDT switch, eliminating the need for separate attenuator components and reducing overall insertion loss while maintaining fast switching capability.
Solution Approach 2:
The SPDT switch circuit is designed to perform multiple functions: it provides fast switching between two outputs and simultaneously provides attenuation control through the embedded attenuator circuit. The same circuit structure handles both switching and attenuation, making the device multi-functional and reducing the number of separate components needed.
2Adaptability or versatility
If an SPDT switch is designed with inductors and resistors in the transmitter and receiver switches, then attenuation control is improved, but the switch area increases
Solution Approach 1:
The attenuator circuit is merged with the SPDT switch circuit into a single integrated structure. The series switching elements and shunt switching elements of the attenuator are directly connected to the common input node and output nodes of the SPDT switch, eliminating the need for separate inductor and resistor components that would increase die area.
Solution Approach 2:
The patent uses switching elements (transistors) that can change their electrical parameters (resistance, conductance) based on control signals. By adjusting the state of the series and shunt switching elements, the attenuation level can be dynamically controlled without requiring physical changes or additional components, thus reducing the overall switch area while maintaining attenuation control capability.
Data Source
AI summary
A single pole double throw (SPDT) switch with embedded attenuators includes a transmitter attenuator circuit directly connected to a common input of the SPDT switch, and a receiver attenuator circuit directly connected to the common input of the SPDT switch. Switches in the transmitter attenuator circuit and in the receiver attenuator circuit are selectively or individually set to an open state or to a closed state to directly connect the transmitter attenuator circuit or the receiver attenuator circuit to the common input. The selective setting of the states of the switches also determines a given amount of attenuation for the transmitter attenuator circuit or the receiver attenuator circuit.