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Trap filter and low pass filter

A technology of notch filter and operational amplifier, applied in impedance network, electrical components, multi-terminal pair network, etc., can solve the problems such as the center frequency of notch filter can not reach the suppression of power frequency interference, the problem of filter frequency control, and the damage of circuit performance.

Active Publication Date: 2012-02-15
SHENZHEN INST OF ADVANCED TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in modern microelectronics technology, the resistance integrated in the chip generally does not exceed 500KΩ, and the capacitance does not exceed 50pF. This is because if the integrated resistance or integrated capacitance exceeds these values, their nonlinearity will greatly damage the performance of the circuit, and the gain outweighs the gain.
Under such limitations, the center frequency of the notch filter cannot meet the requirements for suppressing power frequency interference
[0005] The integrated filter also has the above-mentioned filter frequency control problem

Method used

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  • Trap filter and low pass filter
  • Trap filter and low pass filter
  • Trap filter and low pass filter

Examples

Experimental program
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Embodiment Construction

[0021] Such as figure 1 Shown is a notch filter of an embodiment. The wave trap includes a first integrating circuit 100 , a unity gain inverting circuit 200 and a second integrating circuit 300 connected in sequence.

[0022] The first integrating circuit 100 includes an operational amplifier U1, a capacitor C1 connected between the output terminal and the inverting input terminal of the operational amplifier U1, and a current control circuit 102 and a resistor R1 connected in sequence to the inverting input terminal of the operational amplifier U1, wherein The current control circuit 102 is connected between the inverting input terminal of the operational amplifier U1 and the resistor R1. The input of the notch filter V in It is connected to the current control circuit 102 through the resistor R1.

[0023] The second integration circuit 300 includes an operational amplifier U2, a capacitor C2 connected between the output terminal and the inverting input terminal of the op...

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PUM

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Abstract

The invention discloses a trap filter which comprises a first integrating circuit, a unit gain anti-phase circuit and a second integrating circuit. An input terminal of the first integrating circuit is an input terminal of the trap filter, an output terminal of the second integrating circuit is an output terminal of the trap filter, a feedforward capacitor connects the input terminal with a feedback input terminal of the second integrating circuit, a feedback resistor and a feedback capacitor are in parallel connection between the output terminal and a feedback input terminal of the first integrating circuit, and a current control circuit connects the first integrating circuit with an anti-phase input terminal of an operational amplifier in the second integrating circuit. The invention also discloses a low pass filter, wherein an integrating circuit has a same structure of the above trap filter. An integrator has a large time constant, using a large resistor and a large capacitor can be avoided, and integration becomes simple.

Description

【Technical field】 [0001] The invention relates to an integrated circuit, in particular to a notch filter in the integrated circuit, and also to a low-pass filter. 【Background technique】 [0002] In analog circuit design, notch filters are usually used to suppress or eliminate specific frequency interference. Because power frequency (50Hz or 60Hz) interference is ubiquitous, many instruments and equipment (such as ECG monitors, etc.) contain traps to suppress this power frequency interference. [0003] This notch filter is generally welded on a printed circuit board (PCB) with discrete resistors, discrete capacitors and operational amplifiers. However, the notch filter formed by soldering PCB in this way not only has high power consumption and large volume, but also has low precision. [0004] Integrating all the traps in one chip can eliminate the problems of the traps mentioned above. However, in modern microelectronics technology, the resistance integrated in the chip g...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03H7/06H03H7/46
Inventor 李海希张金勇王磊
Owner SHENZHEN INST OF ADVANCED TECH CHINESE ACAD OF SCI
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