Crystal Oscillation Circuit With Adjustable Load Capacitance
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Solution Overview
Problem
Existing semiconductor chips struggle to generate oscillation signals using crystal resonators with different characteristics, as they fail to maintain oscillation frequency and negative resistance within standard ranges when the resonator is replaced, due to inadequate load capacitance adjustment and temperature compensation.
Innovation Solution
The semiconductor apparatus includes external terminals connected to a piezoelectric vibrator, an inverting amplifier with feedback resistance, and capacitative and resistive elements in series, allowing for adjustable load capacitance and internal parallel elements to maintain oscillation frequency and negative resistance within standard ranges across various resonators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the semiconductor chip is designed with fixed capacitance values for a specific crystal resonator, then the oscillation circuit can operate correctly with that resonator, but it cannot generate oscillation signals with crystal resonators having different characteristics
Solution Approach 1:
The patent applies dynamics by making the capacitance values adjustable rather than fixed. Switches are connected in parallel with the capacitors, allowing the capacitance values to be dynamically changed by switching between different capacitor configurations. This enables the oscillation circuit to adapt to different crystal resonator characteristics while maintaining a relatively simple circuit structure.
Solution Approach 2:
The patent changes the electrical parameters (capacitance values) of the circuit to match different crystal resonator requirements. By providing multiple capacitor values and using switches to select appropriate combinations, the circuit can accommodate various resonators with different oscillation frequencies and load capacitance requirements without redesigning the entire circuit.
2Adaptability or versatility
If the semiconductor chip uses temperature compensation circuits on one side only, then the circuit can be simplified, but it becomes difficult to maintain oscillation frequency and negative resistance within standard ranges when replacing crystal resonators
Solution Approach 1:
The patent makes the oscillation circuit universal by designing it to work with multiple types of crystal resonators. The circuit incorporates adjustable capacitance elements that can be configured to match the specific requirements of different resonators, allowing a single chip design to serve multiple applications and resonator types while maintaining reliable oscillation characteristics.
3Adaptability or versatility
If the inverter size is fixed, then the circuit design is simplified, but the oscillation frequency and negative resistance cannot be maintained within standard ranges when crystal resonators are replaced
Solution Approach 1:
The patent applies dynamics by making the capacitance values adjustable rather than fixed. Switches are connected in parallel with the capacitors, allowing the capacitance values to be dynamically changed by switching between different capacitor configurations. This enables the oscillation circuit to adapt to different crystal resonator characteristics while maintaining a relatively simple circuit structure.
Solution Approach 2:
The patent changes the electrical parameters (capacitance values) of the circuit to match different crystal resonator requirements. By providing multiple capacitor values and using switches to select appropriate combinations, the circuit can accommodate various resonators with different oscillation frequencies and load capacitance requirements without redesigning the entire circuit.
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 enables easy generation of oscillation signals using various piezoelectric vibrators with different characteristics by adjusting load capacitance and maintaining oscillation frequency and negative resistance within specified ranges.
Implementation Method 1
first and second external terminals connected to respective both ends of a piezoelectric vibrator
Implementation Method 2
first capacitative element connected between the first external terminal and a reference voltage terminal; second capacitative element connected between the second external terminal and the reference voltage terminal
Data Source
AI summary
A semiconductor apparatus includes: first and second external terminals that are connected to respective both ends of an piezoelectric vibrator, in which the piezoelectric vibrator is externally disposed; an inverting amplifier that is disposed between the first and second external terminals; a feedback resistance that feeds back an output of the inverting amplifier to an input of the inverting amplifier; a first capacitative element that is disposed between the first external terminal and a reference voltage terminal; a first resistive element that is disposed in series with the first capacitative element; a second capacitative element that is disposed between the second external terminal and the reference voltage terminal; and a second resistive element that is disposed in series with the second capacitative element.