CN105811918B - High-pass filter start-up circuit - Google Patents
High-pass filter start-up circuit Download PDFInfo
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- CN105811918B CN105811918B CN201410854479.5A CN201410854479A CN105811918B CN 105811918 B CN105811918 B CN 105811918B CN 201410854479 A CN201410854479 A CN 201410854479A CN 105811918 B CN105811918 B CN 105811918B
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- pass filter
- circuit
- hpf
- input terminal
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Abstract
The present invention provides a kind of high-pass filter start-up circuits, including cascade multiple operational amplifiers, the forward and reverse input terminal of each operational amplifier is separately connected the cathode of the first and second diodes, and the anode of first and second diode is commonly connected to accessory power supply.The start-up circuit of high-pass filter of the invention can efficiently solve the problem of high-pass filter cannot normally start.
Description
Technical field
The present invention relates to a kind of start-up circuits of high-pass filter.
Background technique
General general-purpose chip will appear the case where HPF (high-pass filter) cannot start in test.It cannot be opened in HPF
Input terminal when dynamic in chip artificially adds a biggish pumping signal, or on chip power artificially plus one biggish is swashed
After encouraging signal, HPF can normally start work.
The circuit topological structure of HPF as shown in Figure 1, if all capacitive branch in Fig. 1 removed, it is available such as
Direct current topological circuit shown in Fig. 2.4 operational amplifiers in Fig. 2 are divided into two groups, and every group of two operational amplifiers pass through resistance
Head and the tail connect, and constitute closed loop configuration, this structure can be further simplified as Fig. 3, the structure of operational amplifier therein such as Fig. 4 institute
Show.
Be can analyze out according to the structure of above-mentioned HPF, HPF when input and output are low level there are a stable state, when
When larger fluctuation occur in the input of HPF or power supply, HPF can be made to be detached from this stable state and enter normal operating conditions.
Therefore, to solve the problems, such as that HPF cannot normally start to normal operating conditions, it is necessary to optimize the starting electricity of HPF
Road.
Summary of the invention
For this purpose, the present invention provides a kind of high-pass filter start-up circuit, including cascade multiple operational amplifiers, each
The forward and reverse input terminal of the operational amplifier is separately connected the cathode of the first and second diodes, and described first and second
The anode of diode is commonly connected to accessory power supply.
What the start-up circuit of high-pass filter of the invention can efficiently solve that high-pass filter cannot normally start asks
Topic.
Detailed description of the invention
Fig. 1 is the electrical block diagram of high-pass filter；
Fig. 2 is the DC circuit structural schematic diagram of Fig. 1；
Fig. 3 is the simplification circuit structure diagram of one group of operational amplifier in Fig. 2；
Fig. 4 is the structural schematic diagram of operational amplifier in Fig. 3；
Fig. 5 is the structural schematic diagram of the start-up circuit of high-pass filter of the invention.
Specific embodiment
The start-up circuit of high-pass filter of the invention is made with reference to the accompanying drawings and detailed description further detailed
Thin description, but it is not as a limitation of the invention.
It is the structural schematic diagram of the start-up circuit of high-pass filter of the invention referring to Fig. 5.HPF 4 amplifiers it is defeated
Enter end, is separately added into a pair of diodes.Diode cathode connects the input terminal of amplifier, and the other end connects VCM level.
Amplifier incoming level is drawn high VCM-VTH by the diode current flow when circuit enters low level stable state, wherein
VTH is the conducting voltage of diode, so that amplifier starting, quickly enters normal operating conditions.
The above specific embodiment is only exemplary embodiments of the present invention, it is impossible to be used in limits the present invention, the present invention
Protection scope be defined by the claims.Those skilled in the art can within the spirit and scope of the present invention, to this
Various modifications or equivalent replacements are made in invention, these modifications or equivalent replacement also should be regarded as being within the scope of the present invention.
Claims (1)
1. a kind of high-pass filter start-up circuit, which is characterized in that including cascade multiple operational amplifiers, each operation
The forward and reverse input terminal of amplifier is separately connected the cathode of the first and second diodes, first and second diode
Anode is commonly connected to accessory power supply.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410854479.5A CN105811918B (en) | 2014-12-30 | 2014-12-30 | High-pass filter start-up circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410854479.5A CN105811918B (en) | 2014-12-30 | 2014-12-30 | High-pass filter start-up circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN105811918A CN105811918A (en) | 2016-07-27 |
| CN105811918B true CN105811918B (en) | 2019-01-04 |
Family
ID=56465218
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410854479.5A Active CN105811918B (en) | 2014-12-30 | 2014-12-30 | High-pass filter start-up circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN105811918B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4533965A (en) * | 1984-04-18 | 1985-08-06 | General Signal Corporation | Magnetic read/write circuit |
| CN85100788A (en) * | 1985-04-20 | 1986-10-29 | 株式会社日立制作所 | Automatic control for frequency characteristics of filter integrated |
| CN101825725A (en) * | 2009-03-03 | 2010-09-08 | 欧姆龙株式会社 | Light receiving detection circuit |
-
2014
- 2014-12-30 CN CN201410854479.5A patent/CN105811918B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4533965A (en) * | 1984-04-18 | 1985-08-06 | General Signal Corporation | Magnetic read/write circuit |
| CN85100788A (en) * | 1985-04-20 | 1986-10-29 | 株式会社日立制作所 | Automatic control for frequency characteristics of filter integrated |
| CN101825725A (en) * | 2009-03-03 | 2010-09-08 | 欧姆龙株式会社 | Light receiving detection circuit |
Also Published As
| Publication number | Publication date |
|---|---|
| CN105811918A (en) | 2016-07-27 |
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