CN204425284U - A kind of automatic gain control circuit - Google Patents
A kind of automatic gain control circuit Download PDFInfo
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- CN204425284U CN204425284U CN201520093279.2U CN201520093279U CN204425284U CN 204425284 U CN204425284 U CN 204425284U CN 201520093279 U CN201520093279 U CN 201520093279U CN 204425284 U CN204425284 U CN 204425284U
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Abstract
The utility model discloses a kind of automatic gain control circuit, comprise adjustable gain amplification module; The negative output terminal of described adjustable gain amplification module and positive output end are connected respectively to one end of two comparators; The other end of described two comparators is electrically connected to reference voltage module; Described comparator is electrically connected to or the input of door; Output that is described or door is connected to the input up control end of charge pump by a not gate; Output that is described or door is also directly electrically connected the input dn control end of charge pump; The output control terminal of described charge pump is electrically connected a gain control capacitance; The output control terminal of described charge pump is also electrically connected the control end of adjustable gain amplification module.Automatic gain control circuit of the present utility model, does not need peak detector to participate in, and circuit is more simple, also makes circuit performance substantially reduce by the impact of technique and variations in temperature simultaneously, and the scope of application is wider, is specially adapted to ofdm system.
Description
Technical field
The utility model relates to a kind of automatic gain control circuit, belongs to ofdm system technical field.
Background technology
Automatic gain control circuit is the process automatically adjusted to the gain of amplifier; The output signal level normally caused to make to change with incoming signal level is with low uncertainty; It is a module important in ofdm system; Automatic gain control circuit is close loop electronic circuit, is a degeneration factor, and it can be divided into gain controlled amplifying circuit and control voltage forms circuit two parts; Gain controlled amplifying circuit is positioned at forward and amplifies path, and its gain changes with control voltage; The basic element of character that control voltage forms circuit is AGC wave detector and low pass smoothing filter, sometimes also comprises the parts such as gate circuit and direct current amplifier; The output signal uo of amplifying circuit is through detection and after filter filtering low frequency modulations component and noise, produce the voltage uc in order to ride gain controlled amplifier.When input signal ui increases, uo and uc also increases thereupon.Uc increases makes the gain of amplifying circuit decline, thus makes the variable quantity of output signal significantly be less than the variable quantity of input signal, reaches the object of automatic growth control; Existing automatic gain control circuit is primarily of variable-gain amplification circuit, peak detection circuit, comparator, loop filter 4 submodule compositions; Because it has used peak detector, be often subject to the restriction of useful frequency when designing, particularly in low supply voltage CMOS technique, circuit is very large by the impact of technique and variations in temperature.
Utility model content
(1) technical problem that will solve
For solving the problem, the utility model proposes a kind of automatic gain control circuit, adopt comparator scheme, be highly suitable for ofdm system, the scope of application is wider.
(2) technical scheme
Automatic gain control circuit of the present utility model, comprises adjustable gain amplification module; The negative output terminal of described adjustable gain amplification module and positive output end are connected respectively to one end of two comparators; The other end of described two comparators is electrically connected to reference voltage module; Described comparator is electrically connected to or the input of door; Output that is described or door is connected to the input up control end of charge pump by a not gate; Output that is described or door is also directly electrically connected the input dn control end of charge pump; The output control terminal of described charge pump is electrically connected a gain control capacitance; The output control terminal of described charge pump is also electrically connected the control end of adjustable gain amplification module.
Further, described adjustable gain amplification module is made up of a variable gain amplifying stage cascade fixed gain level; The control end of the output control terminal electrical connection variable gain amplifying stage of described charge pump.
Again further, the gilbert circuit that described variable gain amplifying stage is controlled by analog signal is formed.
Further, described reference voltage module is by reference voltage chip, and peripheral circuit is formed.
(3) beneficial effect
Compared with prior art, automatic gain control circuit of the present utility model, does not need peak detector to participate in, circuit is simpler, also make circuit performance substantially reduce by the impact of technique and variations in temperature, the scope of application is wider, is specially adapted to ofdm system simultaneously.
Accompanying drawing explanation
Fig. 1 is module diagram of the present utility model.
Embodiment
Automatic gain control circuit as shown in Figure 1, comprises adjustable gain amplification module; The negative output terminal of described adjustable gain amplification module and positive output end are connected respectively to one end of two comparators; The other end of described two comparators is electrically connected to reference voltage module; Described comparator is electrically connected to or the input of door; Output that is described or door is connected to the input up control end of charge pump by a not gate; Output that is described or door is also directly electrically connected the input dn control end of charge pump; The output control terminal of described charge pump is electrically connected a gain control capacitance; The output control terminal of described charge pump is also electrically connected the control end of adjustable gain amplification module.
Wherein, described adjustable gain amplification module is made up of a variable gain amplifying stage cascade fixed gain level; The control end of the output control terminal electrical connection variable gain amplifying stage of described charge pump; The gilbert circuit that described variable gain amplifying stage is controlled by analog signal is formed; Described reference voltage module is by reference voltage chip, and peripheral circuit is formed.
Because variable gain amplifying stage is made up of gilbert circuit, it can be controlled by analog signal, can coordinate with capacitor charge and discharge, and fixed gain level uses relatively more flexible, can adopt multiple available circuit, as differential amplifier circuit etc.
During use, input signal its output instantaneous value after adjustable gain amplification module amplifies compares with a reference voltage Vref, and when it is greater than Vref, charge pump is in charged state, on the contrary charge pump electric discharge; The voltage control that charge pump charging and discharging currents is formed on electric capacity C the gain of the variable gain amplifying stage of adjustable gain amplification module, when meeting I1*t1=I2*t2; T1+t2=T; Time, this charge pump is in poised state; Wherein, I1, I2 represent constant charging and discharging currents respectively, and t1, t2 are then the charge and discharge time.Namely, as Vout > Vref, charge pump is in charging interval t1, and as Vout < Vref, charge pump is in t2 discharge time.
Embodiment recited above is only be described preferred implementation of the present utility model, not limits design of the present utility model and scope.Under the prerequisite not departing from the utility model design concept; the various modification that this area ordinary person makes the technical solution of the utility model and improvement; protection range of the present utility model all should be dropped into; the technology contents of the utility model request protection, all records in detail in the claims.
Claims (4)
1. an automatic gain control circuit, is characterized in that: comprise adjustable gain amplification module; The negative output terminal of described adjustable gain amplification module and positive output end are connected respectively to one end of two comparators; The other end of described two comparators is electrically connected to reference voltage module; Described comparator is electrically connected to or the input of door; Output that is described or door is connected to the input up control end of charge pump by a not gate; Output that is described or door is also directly electrically connected the input dn control end of charge pump; The output control terminal of described charge pump is electrically connected a gain control capacitance; The output control terminal of described charge pump is also electrically connected the control end of adjustable gain amplification module.
2. automatic gain control circuit according to claim 1, is characterized in that: described adjustable gain amplification module is made up of a variable gain amplifying stage cascade fixed gain level; The control end of the output control terminal electrical connection variable gain amplifying stage of described charge pump.
3. automatic gain control circuit according to claim 2, is characterized in that: the gilbert circuit that described variable gain amplifying stage is controlled by analog signal is formed.
4. automatic gain control circuit according to claim 1, is characterized in that: described reference voltage module is by reference voltage chip, and peripheral circuit is formed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520093279.2U CN204425284U (en) | 2015-02-10 | 2015-02-10 | A kind of automatic gain control circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520093279.2U CN204425284U (en) | 2015-02-10 | 2015-02-10 | A kind of automatic gain control circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204425284U true CN204425284U (en) | 2015-06-24 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201520093279.2U Active CN204425284U (en) | 2015-02-10 | 2015-02-10 | A kind of automatic gain control circuit |
Country Status (1)
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| CN (1) | CN204425284U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108233883A (en) * | 2016-12-15 | 2018-06-29 | 江苏安其威微电子科技有限公司 | The control device of signal amplitude |
| CN111246049A (en) * | 2020-03-25 | 2020-06-05 | 上海集成电路研发中心有限公司 | Motion detection structure and motion detection method applied to CIS |
| CN113098537A (en) * | 2021-04-06 | 2021-07-09 | 上海航天电子通讯设备研究所 | Automatic gain control receiver for time division digital communication system |
-
2015
- 2015-02-10 CN CN201520093279.2U patent/CN204425284U/en active Active
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108233883A (en) * | 2016-12-15 | 2018-06-29 | 江苏安其威微电子科技有限公司 | The control device of signal amplitude |
| CN108233883B (en) * | 2016-12-15 | 2024-02-23 | 上海安其威微电子科技有限公司 | Signal amplitude control device |
| CN111246049A (en) * | 2020-03-25 | 2020-06-05 | 上海集成电路研发中心有限公司 | Motion detection structure and motion detection method applied to CIS |
| CN111246049B (en) * | 2020-03-25 | 2022-07-19 | 上海集成电路研发中心有限公司 | Movement detection structure and movement detection method applied to CIS |
| CN113098537A (en) * | 2021-04-06 | 2021-07-09 | 上海航天电子通讯设备研究所 | Automatic gain control receiver for time division digital communication system |
| CN113098537B (en) * | 2021-04-06 | 2022-05-27 | 上海航天电子通讯设备研究所 | Automatic gain control receiver for time division digital communication system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20190703 Address after: 644000 Standard Factory Building No. 11, Intelligent Terminal Industrial Park, Songjiazhen, Cuiping District, Yibin City, Sichuan Province Patentee after: Yibin Zeping Intelligent Electronic Equipment Manufacturing Co., Ltd. Address before: 215123 No. 99 Renai Road, Suzhou Industrial Park, Suzhou City, Jiangsu Province Patentee before: Suzhou Si Yuan leads to Science and Technology Ltd. |