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Broad band charge amplifier and design method thereof

A charge amplifier and wide-band technology, applied in charge amplifiers, improved amplifiers to expand bandwidth, etc., can solve problems such as insulation resistance reduction and resistance devices being meaningless

Active Publication Date: 2011-06-22
北京唐智科技发展有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The problem is: when the frequency is as low as f0=7.98Hz, the transfer characteristics of the known charge amplifier (as attached figure 2 Shown), the drop is -3.01dB, the frequency f0 is called the "corner frequency", when the frequency is as low as 0.01Hz, the transmission characteristics drop to -58dB
Although modern high-performance op amps can operate at R 1 The working point of the charge amplifier is also guaranteed to be normal under the condition of 1GΩ. However, a resistance device as high as 1GΩ is almost meaningless in the detection circuit of the engineering site, because the circuit board on which the device is installed is affected by environmental humidity and dust, so that its insulation The resistance is often reduced to the order of 10MΩ

Method used

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  • Broad band charge amplifier and design method thereof
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  • Broad band charge amplifier and design method thereof

Examples

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Effect test

Embodiment 1

[0097] Embodiment 1, Feedback Bypass Low Frequency Single-Ended Charge Amplifier

[0098] The principle of the feedback bypass type low-frequency charge amplifier technology proposed by the present invention is to connect the capacitor in series with the resistor C 2 +R 3 The branch puts the resistor R 11 with resistor R 12 The connection point V F The alternating potential of the resistor F is pulled towards the potential of the reference point G without adding appreciable phase shift, causing the resistor F 11 Same as op amp OP 1 The effect of AC grounding at the negative input terminal of the op amp is to fully reduce the negative input terminal of the op amp from the op amp OP 1 output, except C 1 External AC negative feedback, thereby improving the low-frequency frequency response.

[0099] This broadband charge amplifier (see attached Pic 4-1 , 4-2 ), including the op amp OP 1 , resistor R 11 , R 12 , R 3 , capacitor C1 、C 2 , op amp OP 1 The positive pow...

Embodiment 2

[0155] Embodiment 2 is a single-supply single-ended input broadband charge amplifier

[0156] as attached Figure 7 A single-supply single-ended input wide-band charge amplifier is shown, which is used in occasions where there is only a single power supply, and its characteristic is that it contains an operational amplifier OP 1 , OP 2 , resistor R 1 ~R 3 , R 11 , R 12 , capacitor C 1 ~C 3 , the positive power supply terminal of each op amp is connected to the positive power supply terminal V DD , the ground wire GND of the negative power supply terminal of the op amp, and the resistor R 1 One end of the ground, the other end of the op amp OP 2 the positive input and the resistor R 2 one end of the capacitor C 3 One end of the capacitor C 3 The other end of the ground is GND, the resistor R 2 The other end is connected to the positive power supply terminal V DD , op amp OP 2 The output terminal of the output terminal is connected to its negative input terminal, ...

Embodiment 3

[0157] Embodiment 3 is a differential input broadband charge amplifier

[0158] as attached Figure 8 The shown differential input broadband charge amplifier is aimed at improving the anti-interference ability, and is characterized in that it is provided with input terminals Q+, Q- and reference terminal G of the charge signal source, and is provided with a charge-voltage conversion device for the Q+ signal. Positive charge converter and negative charge converter for charge-to-voltage conversion of Q-signal; positive charge converter contains operational amplifier OP 1 , resistor R 11 , R 12 , the feedback capacitor C 11 , op amp OP 1 The positive input terminal is connected to the reference terminal G, the negative input terminal is connected to the positive charge input terminal Q+, and also connected to the resistor R 11 One end of the resistor R 11 The other end of the resistor R 12 One end of the resistor R 12 The other end of the op amp OP 1 The output of the ne...

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Abstract

A wide frequency band charge amplifier is used to change charge voltage, which is characterized in that a feedback resistance which is jumped between a negative input end and output end of an operational amplifier to an R11, R12 series circuit in the widely-known charge amplifier circuit, a reference end G is connected with a feedback by-passing branch through a connecting point of the R11, R12, the feedback by-passing branch is formed through connecting R3 and C2 in series, when R11=R12=R, the connected feedback by-passing branch can lead a breaking frequency f0 of a charge amplifier output end V0 without the feedback by-passing branch to reduce to f1=f0 / X, a proposed design formula of the technical principle that a resistance with a low electrical resistance value is used to design even low frequency charge amplifier is: R3 = 0.5R*2<0.5>, C2 = 2XRC1 / R3, therefore, low-frequency characteristic of the widely-known charge amplifier which is only applied to the medium high frequency is optimized, and the wide frequency band charge amplifier is realized.

Description

Technical field: [0001] The invention relates to a charge amplifier and its design method, especially a broadband charge amplifier with good low-frequency characteristics, which belongs to the signal detection technology category of equipment fault diagnosis technology, and is mainly used for processing sensors with piezoelectric ceramics as sensitive devices The generated charge signal solves the technical problem of low-frequency charge signal detection. Background technique [0002] In the prior art, there are charge amplifiers for detecting intermediate frequency and high frequency piezoelectric signals, and there are charge amplifiers for detecting low frequency piezoelectric signals. The typical way is to use parallel voltage amplifier integrators composed of operational amplifiers to form the following figure 1 The actual technical content of the circuit is "charge-to-voltage converter", and its high-frequency characteristics only depend on the high-frequency characte...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H03F3/70H03F1/42
Inventor 唐德尧王定晓王巍松
Owner 北京唐智科技发展有限公司