TCXO Circuit Layout for Accurate Temperature Sensing
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Solution Overview
Problem
In temperature-compensated crystal oscillators (TCXOs), frequency fluctuations occur due to temperature changes, and existing designs may inaccurately detect temperature when the output buffer circuit and temperature sensor circuit are proximal, leading to potential frequency instability.
Innovation Solution
The semiconductor circuit device incorporates a layout where the output circuit and temperature sensing element are positioned to minimize thermal influence, with the output circuit's heat dissipated through dedicated terminals or wiring, ensuring accurate temperature detection and reduced frequency fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the output buffer circuit is placed close to the temperature sensor circuit to reduce device area, then area is reduced, but temperature detection accuracy deteriorates due to thermal interference
Solution Approach 1:
The patent extracts the output buffer circuit from the vicinity of the temperature sensor circuit by providing separate connection terminals. The output circuit is connected to a first connection terminal while the temperature sensor circuit is connected to a second connection terminal, physically separating the heat-generating output stage from the sensitive temperature detection stage through dedicated terminal pathways.
Solution Approach 2:
The patent introduces connection terminals as intermediary elements between the output buffer circuit and the external environment. These terminals serve as heat dissipation pathways that mediate the thermal interaction, allowing heat to be conducted away from the semiconductor substrate through the terminals rather than accumulating near the temperature sensor.
2Device complexity
If the output buffer circuit is placed close to the temperature sensor circuit to simplify layout, then layout complexity is reduced, but frequency stability deteriorates due to thermal influence on oscillation
Solution Approach 1:
The patent extracts the thermal influence pathway by separating the connection terminals for the output circuit and temperature sensor circuit. This physical separation through dedicated terminals removes the harmful thermal coupling that would otherwise cause frequency fluctuations in the oscillation circuit.
Solution Approach 2:
The connection terminals act as intermediary heat dissipation pathways that protect the oscillation circuit from thermal interference. By providing dedicated terminal connections for the output buffer, the patent creates a controlled thermal pathway that prevents heat from reaching the temperature-sensitive oscillation and sensing circuits.
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 frequency fluctuations by effectively dissipating heat away from the temperature sensing element, allowing for precise temperature detection and improved frequency stability in TCXOs.
Implementation Method 1
a temperature of the output buffer circuit is easily transferred to the temperature sensor circuit
Implementation Method 2
heat generated from the output circuit which is one of heat generation sources is dissipated via the first connection terminal
Data Source
AI summary
A semiconductor circuit device includes an oscillation circuit, an output circuit that receives a signal output from an oscillation circuit and outputs an oscillation signal, a temperature sensing element, a characteristic adjustment circuit that adjusts characteristics of the oscillation circuit on the basis of a signal output from the temperature sensing element, and a first connection terminal that is electrically connected to the output circuit and via which the oscillation signal is output, in which a distance between the output circuit and the first connection terminal is shorter than a distance between the temperature sensing element and the first connection terminal in a plan view.