Crystal Oscillator Circuit With Fast Start-Up and Lower Power
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Solution Overview
Problem
Conventional crystal oscillation circuits take a long time to stabilize oscillation frequency and amplitude, which is undesirable in battery-powered devices where power savings are crucial.
Innovation Solution
An oscillation circuit design incorporating a piezoelectric oscillator, resistive and capacitative elements, and a first exciting circuit with multiple cascade-connected logic elements for high power amplification, along with a second exciting circuit with lower power amplification for reduced start-up time and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a conventional crystal oscillation circuit is used, then oscillation can be generated, but start-up time is long
Solution Approach 1:
The exciting circuit is divided into multiple stages (first exciting circuit with high power amplification and second exciting circuit with low power amplification). Each stage serves a specific function: the first stage provides strong initial excitation to reduce start-up time, while the second stage maintains oscillation with lower power consumption. This segmentation allows the system to optimize performance at different operating phases without excessive complexity.
Solution Approach 2:
The circuit dynamically switches between different exciting circuits based on the oscillation state. During start-up, the first exciting circuit is activated to provide high power amplification. Once oscillation is established, the circuit transitions to using the second exciting circuit for normal operation. This dynamic adaptation resolves the contradiction by providing high power only when necessary.
2Loss of time
If power amplification is increased to reduce start-up time, then start-up time decreases, but power consumption increases
Solution Approach 1:
The circuit employs periodic switching between high power amplification mode (during start-up) and low power amplification mode (during normal operation). The first exciting circuit operates periodically only during the initial phase to establish oscillation, then the second exciting circuit takes over for sustained operation. This periodic action pattern allows the system to achieve fast start-up without continuously consuming high power.
Solution Approach 2:
The power amplification parameter is changed based on the operational phase. During start-up, high power amplification is applied to quickly establish oscillation. After oscillation is stable, the power amplification parameter is reduced to lower power consumption level. This parameter change strategy directly addresses the contradiction by adjusting power levels according to actual needs.
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
The design significantly reduces start-up time and power consumption by utilizing high power amplification during initialization and lower power amplification when stabilized, enhancing the efficiency of battery-powered devices.
Implementation Method 1
a piezoelectric oscillator (such as a crystal oscillator, a ceramic oscillator)
Implementation Method 2
The first exciting circuit includes a plurality of cascade-connected logic elements each used as an amplifier circuit
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
An oscillation circuit (1) includes a piezoelectric oscillator (XO), a resistive element (R1), and an exciting circuit (10) connected between an input node (XIN) and an output node (XOUT) in parallel with one another, a first capacitor (C1) connected between the input node (XIN) and a ground node (GND), and a second capacitor (C2) connected between the output node (XOUT) and the ground node (GND). The exciting circuit (10) includes a NAND circuit (L1) and first and second inverters (L2, L3) that are cascade-connected. Oscillation of the piezoelectric oscillator (XO) is started when an enable signal (Enable) input to the NAND circuit (L1) is switched to an H level (active state).