Low-Power Crystal Oscillator Buffer Circuit for Crystal Variation
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Solution Overview
Problem
Existing crystal oscillators are limited by crystal-to-crystal variations and have high energy consumption, which restricts their use in battery-powered applications and reduces the number of available suppliers.
Innovation Solution
A low power crystal oscillator design featuring a configurable gain P-channel transistor and a buffer circuit, allowing it to accommodate a wide range of crystals and minimize energy consumption, with a buffer circuit providing a clock signal based on the oscillator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a crystal oscillator is customized for a specific supplier's physical crystal to minimize costs, then manufacturing cost is reduced, but the number of available suppliers is limited due to crystal-to-crystal variations
Solution Approach 1:
The patent implements dynamic gain control in the oscillator circuit, allowing the gain to be adjusted based on the specific crystal characteristics. This enables the same oscillator circuit to adapt to crystals from different suppliers with varying parameters, resolving the contradiction between cost optimization through customization and supplier versatility.
Solution Approach 2:
The patent changes the electrical parameters of the oscillator circuit, specifically the gain parameter, to match different crystal characteristics. By adjusting the gain parameter, the oscillator can work with crystals from multiple suppliers without requiring custom-designed circuits for each supplier, thus maintaining low costs while increasing supplier compatibility.
2Reliability
If traditional crystal oscillators are used in battery-powered applications, then clock signal generation is achieved, but energy consumption is high which reduces battery life
Solution Approach 1:
The patent employs periodic gain modulation rather than continuous high-gain operation. The gain is adjusted periodically or in discrete steps based on operating conditions, allowing the oscillator to maintain reliable clock signal generation while reducing average energy consumption compared to traditional continuously high-gain oscillators.
Solution Approach 2:
The patent dynamically changes the gain parameter of the oscillator based on operating conditions such as temperature and crystal aging. This parameter adaptation allows the oscillator to maintain stable operation with lower energy consumption by optimizing the gain level rather than using fixed high gain, thus extending battery life while ensuring reliable clock signal generation.
Data Source
AI summary
A low power crystal oscillator is provided. The crystal oscillator includes a gain control stage, a filter stage, and an output stage. The gain control stage includes an input coupled at a first oscillator terminal configured and arranged for connection to a first terminal of a crystal. The filter stage includes an input coupled to an output of the gain control stage. The output stage includes a first transistor having a first current electrode coupled at a second oscillator terminal configured and arranged for connection to a second terminal of the crystal and a control electrode coupled to receive a voltage signal at the first oscillator terminal and a first bias voltage.