Gyrosensor Detection Circuit With Split Op-Amps for Low-Noise Sensing
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Solution Overview
Problem
Piezoelectric vibrating gyrosensors in electronic devices face challenges in achieving high signal-to-noise ratio (SNR) performance due to weak detection signals, and there is a need to reduce power consumption while maintaining noise reduction and circuit scale efficiency.
Innovation Solution
A detection device with a specific configuration that includes a first-type operational amplifier for amplifying signals and a second-type operational amplifier for filtering, optimized for channel width, channel length, and bias current to reduce thermal and flicker noise, respectively, while minimizing power consumption and circuit area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a normal operational amplifier is used to amplify weak detection signals, then signal amplification is achieved, but power consumption increases and noise reduction performance is insufficient
Solution Approach 1:
The patent divides the operational amplifier into two separate operational amplifiers with different noise characteristics. The first operational amplifier is optimized for amplifying high-frequency carrier signals with low thermal noise, while the second operational amplifier is optimized for low-frequency modulation signals with low flicker noise. This segmentation allows each amplifier to be optimized for its specific frequency range, improving overall signal-to-noise ratio without requiring excessive power consumption from a single amplifier.
Solution Approach 2:
The patent applies different design optimizations to different parts of the signal processing chain. The first operational amplifier uses transistor parameters optimized for high-frequency operation (low thermal noise), while the second operational amplifier uses parameters optimized for low-frequency operation (low flicker noise). This local quality approach ensures that each stage of signal processing has the appropriate noise characteristics for its function, achieving high signal-to-noise ratio performance.
2Weight of stationary object
If the vibrator weight and size are reduced, then device miniaturization is achieved, but detection signal strength decreases
Solution Approach 1:
The patent changes the parameters of the operational amplifiers to compensate for the reduced signal strength from miniaturized vibrators. By optimizing the gain, bandwidth, and noise characteristics of the two-stage amplifier system, the weak signals from small vibrators can be effectively amplified. The first operational amplifier provides high-gain amplification of the carrier signal, while the second operational amplifier provides additional amplification and filtering of the modulated signal, compensating for the reduced signal strength.
3Device complexity
If a single operational amplifier is used for both amplification and filtering, then circuit complexity is reduced, but noise performance and power consumption optimization are compromised
Solution Approach 1:
The patent segments the amplification and filtering functions into two separate operational amplifiers. The first operational amplifier is dedicated to amplifying the high-frequency carrier signal with optimized thermal noise performance. The second operational amplifier is dedicated to amplifying and filtering the low-frequency modulated signal with optimized flicker noise performance. This functional segmentation achieves superior noise performance compared to a single operational amplifier performing both functions.
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 configuration enhances the signal-to-noise ratio and reduces power consumption by selectively using operational amplifiers based on noise frequency characteristics, effectively addressing the limitations of existing piezoelectric vibrating gyrosensors.
Implementation Method 1
an amplifier circuit that amplifies the detection signal from the physical quantity transducer; the amplifier circuit including a first-type operational amplifier; the first-type operational amplifier being an operational amplifier of which thermal noise at a frequency of a carrier signal is lower than that of the second-type operational amplifier
Implementation Method 2
a filter section provided in a subsequent stage of the synchronous detection circuit; the filter section including a second-type operational amplifier; the second-type operational amplifier being an operational amplifier of which flicker noise at a frequency of the desired signal is lower than that of the first-type operational amplifier
Implementation Method 3
A piezoelectric vibrating gyrosensor has attracted attention as one type of gyrosensor. In particular, a crystal piezoelectric vibrating gyrosensor using a crystal as the piezoelectric material
Implementation Method 4
a synchronous detection circuit that synchronously detects the signal amplified by the amplifier circuit
Data Source
AI summary
A detection device includes a detection circuit. The detection circuit includes an amplifier circuit, a synchronous detection circuit, and a filter section. The amplifier circuit includes a first-type operational amplifier, and the filter section includes a second-type operational amplifier. When a channel width and a channel length of a differential-stage transistor of a differential section of the first-type operational amplifier are respectively referred to as W1a and L1a, a bias current flowing through the differential section is referred to as Ia, a channel width and a channel length of a differential-stage transistor of a differential section of the second-type operational amplifier are respectively referred to as W1b and L1b, and a bias current flowing through the differential section is referred to as Ib, W1b×L1b>W1a×L1a and Ia>Ib are satisfied.