CN104753473A - Broadband amplifier - Google Patents
Broadband amplifier Download PDFInfo
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- CN104753473A CN104753473A CN201510128428.9A CN201510128428A CN104753473A CN 104753473 A CN104753473 A CN 104753473A CN 201510128428 A CN201510128428 A CN 201510128428A CN 104753473 A CN104753473 A CN 104753473A
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Abstract
The invention discloses a broadband amplifier. The broadband amplifier comprises a multi-stage current amplifying circuit, an outer feedback circuit, a self-biased circuit and an inner feedback circuit. The multi-stage current amplifying circuit comprises an emitting-electrode follow type primary amplification triode Q2 and a common-emitter type last-stage amplification triode Q3. The inner feedback circuit comprises an inner feedback resistor RFB1, a bias voltage resistor RB1 and a resistor R1. One end of the inner feedback resistor RFB1 is connected with one end of the bias voltage resistor RB1 to form a feed-in point. The outer feedback circuit comprises an outer feedback resistor RFB2, a capacitor C2, an outer feedback capacitor CFB and an outer feedback inductor LFB. The capacitor C2 is connected with the outer feedback capacitor CFB in parallel. The self-biased circuit comprises a bypass capacitor CB and a self-biased triode Q1. A collector electrode of the self-biased triode Q1 is connected with the feed-in point. By means of the broadband amplifier, the purpose that gain reduction is smaller than 0.2 dB within the whole frequency band range is achieved, and the application occasion of the broadband amplifier is broadened.
Description
Technical field
The present invention relates to electroporation field, specifically a kind of wide-band amplifier.
Background technology
Launch at cable TV (CATV) signal and in transmission application, all will use wide-band amplifier (BroadbandAmpli er).Usually said wide-band amplifier, its working frequency range is usually in the scope of 50MHz to 1000MHz.The video amplifier amplified for television image signal is a kind of typical base band type wide-band amplifier, and the frequency range of institute's amplifying signal can from several conspicuous or low frequency of tens hertz until the high frequency of a few megahertz or tens megahertzes.This class A amplifier A is the load of amplifier usually with resistor, does interstage coupling with capacitor.In order to spread bandwidth, except make its gain lower except, usually also need to adopt high and low frequency indemnifying measure, extend to two ends with the flat of the gain-frequency characteristic curve making amplifier.Wide-band amplifier in the market, generally at below 500MHz, can not cause gain reduction.But at more than 500MHz, decaying largely appears in gain.Generally speaking, in the scope of 50MHz to 1000MHz, the decay of gain is usually more than 1dB.And in actual applications, require that the gain reduction of amplifier in whole frequency band is less than 0.5dB.Therefore, the range of application of traditional wide-band amplifier is restricted, and can not meet the gain requirements of band frequently between 500MHz to 1000MHz.
Summary of the invention
The object of the present invention is to provide a kind of wide-band amplifier, to solve the problem proposed in above-mentioned background technology.
For achieving the above object, the invention provides following technical scheme:
A kind of wide-band amplifier, comprises multistage current amplification circuit, external feedback circuit, auto bias circuit and internal feedback circuit, described multistage current amplification circuit comprises first order current amplification circuit and second level current amplification circuit, first order current amplification circuit comprises the elementary amplifying triode Q2 of emitter follower type, the emitter of elementary amplifying triode Q2 is by primary bias current resistor RE2 ground connection, second level current amplification circuit comprises common emitter type final stage amplifying triode Q3, final stage amplifying triode Q3 is by final bias current resistance RE3 ground connection, the base stage of final stage amplifying triode Q3 is connected with electric capacity C1 with the emitter of elementary amplifying triode Q2 respectively, the other end ground connection of electric capacity C1, the base stage of elementary amplifying triode Q2 is as the input of described multistage current amplification circuit, the collector electrode of final stage amplifying triode Q3 is connected with the collector electrode of elementary amplifying triode Q2, and as the output of described multistage current amplification circuit, the i.e. output of whole wide-band amplifier, described internal feedback circuit comprises internal feedback resistance RFB1, bias voltage resistance RB1 and resistance R1, one end of internal feedback resistance RFB1 is connected with one end of bias voltage resistance RB1, form load point, the other end of internal feedback resistance RFB1 is connected with the output of multistage current amplification circuit, the other end of bias voltage resistance RB1 connects the input of wideband amplification circuit, resistance R1 one end connects the input of wideband amplification circuit, and the other end is connected with the input of multistage current amplification circuit, described external feedback circuit comprises external feedback resistance RFB2, electric capacity C2, external feedback electric capacity CFB and external feedback inductance L FB, electric capacity C2 is in parallel with external feedback electric capacity CFB, one end of external feedback resistance RFB2 is connected with one end of external feedback electric capacity CFB, the other end of external feedback resistance RFB2 is connected with one end of external feedback inductance L FB, the other end of external feedback electric capacity CFB is connected with the input of wideband amplification circuit, and the other end of external feedback inductance L FB is connected with the output of described multistage current amplification circuit, described auto bias circuit comprises shunt capacitance CB and automatic biasing triode Q1, the base stage of automatic biasing triode Q1 is connected with the base stage of final stage amplifying triode Q3 by isolation resistance RB2, the base stage of final stage amplifying triode Q3 is by described shunt capacitance CB ground connection, the emitter of automatic biasing triode Q1 is by Self-bias Current resistance RE1 ground connection, and the collector electrode of automatic biasing triode Q1 is connected with described load point.
As the further scheme of the present invention: described electric capacity C2 is electrochemical capacitor, external feedback electric capacity CFB is ceramic disc capacitor.
Compared with prior art, the invention has the beneficial effects as follows: 1, described wide-band amplifier is under the acting in conjunction of the anti-road of inside and outside feedback and auto bias circuit, achieve gain reduction and be less than 0.2dB in whole frequency band range, thus greatly extend the application scenario of this wide-band amplifier; 2, in described wide-band amplifier, electric capacity C2 is electrochemical capacitor, and capacity is large but high frequency characteristics is bad, external feedback electric capacity CFB is ceramic disc capacitor, and high frequency characteristics is good but capacity is little, and both are in parallel, the high frequency characteristics that just can obtain when capacious, increases capacitance, reduces capacitive reactance.
Accompanying drawing explanation
Fig. 1 is the structural representation of wide-band amplifier.
In figure: the multistage current amplification circuit of 101-, 102-external feedback circuit, 103-auto bias circuit, 104-internal feedback circuit.
Embodiment
Be described in more detail below in conjunction with the technical scheme of embodiment to this patent.
Refer to Fig. 1, a kind of wide-band amplifier, comprise the multistage current amplification circuit 101 of the Darlington transistors structure with two-stage Current amplifier, external feedback circuit 102, auto bias circuit 103 and internal feedback circuit 104, described multistage current amplification circuit 101 comprises first order current amplification circuit and second level current amplification circuit, first order current amplification circuit comprises the elementary amplifying triode Q2 of emitter follower type, and the emitter of elementary amplifying triode Q2 is by primary bias current resistor RE2 ground connection, second level current amplification circuit comprises common emitter type final stage amplifying triode Q3, final stage amplifying triode Q3 is by final bias current resistance RE3 ground connection, the base stage of final stage amplifying triode Q3 is connected with electric capacity C1 with the emitter of elementary amplifying triode Q2 respectively, the other end ground connection of electric capacity C1, the base stage of elementary amplifying triode Q2 is as the input of described multistage current amplification circuit 101, the collector electrode of final stage amplifying triode Q3 is connected with the collector electrode of elementary amplifying triode Q2, as the output of described multistage current amplification circuit 101, the i.e. output of whole wide-band amplifier, described internal feedback circuit 104 comprises internal feedback resistance RFB1, bias voltage resistance RB1 and resistance R1, one end of internal feedback resistance RFB1 is connected with one end of bias voltage resistance RB1, form load point, the other end of internal feedback resistance RFB1 is connected with the output of multistage current amplification circuit 101, the other end of bias voltage resistance RB1 connects the input of wideband amplification circuit, resistance R1 one end connects the input of wideband amplification circuit, and the other end is connected with the input of multistage current amplification circuit 101, described external feedback circuit 102 comprises external feedback resistance RFB2, electric capacity C2, external feedback electric capacity CFB and external feedback inductance L FB, electric capacity C2 is in parallel with external feedback electric capacity CFB, described electric capacity C2 is electrochemical capacitor, capacity is large but high frequency characteristics is bad, external feedback electric capacity CFB is ceramic disc capacitor, high frequency characteristics is good but capacity is little, both are in parallel, the high frequency characteristics that just can obtain when capacious, increase capacitance, reduce capacitive reactance, one end of external feedback resistance RFB2 is connected with one end of external feedback electric capacity CFB, the other end of external feedback resistance RFB2 is connected with one end of external feedback inductance L FB, the other end of external feedback electric capacity CFB is connected with the input of wideband amplification circuit, the other end of external feedback inductance L FB is connected with the output of the output of described wideband amplification circuit and multistage current amplification circuit 101, described auto bias circuit 103 comprises shunt capacitance CB and automatic biasing triode Q1, automatic biasing triode Q1 is as the mirror image triode of final stage amplifying triode Q3 in multistage current amplification circuit 101, the base stage of automatic biasing triode Q1 is connected with the base stage of final stage amplifying triode Q3 by isolation resistance RB2, the base stage of final stage amplifying triode Q3 is by described shunt capacitance CB ground connection, the emitter of automatic biasing triode Q1 is by Self-bias Current resistance RE1 ground connection, and the collector electrode of automatic biasing triode Q1 is connected with described load point.
Operation principle of the present invention is: described wide-band amplifier, in multistage current amplification circuit 101, primary bias current resistor RE2 provides DC bias current for elementary amplifying triode Q2, final bias current resistance RE3 provides DC bias current for final stage amplifying triode Q3, in internal feedback circuit 104, the bandwidth sum gain of the whole wide-band amplifier of value effect of internal feedback resistance RFB1, bias voltage resistance RB1 provides base stage DC offset voltage for elementary amplifying triode Q2, outside in feedback circuit 102, the numerical value of external feedback resistance RFB2 also can affect the bandwidth sum gain of whole wide-band amplifier, external feedback electric capacity CFB and electric capacity C2 is ac coupling capacitor (the feedback capacity CFB and electric capacity C2 except for the outer of chip exterior, other is all integrated in chip), utilize the resonance of external feedback inductance L FB and external feedback electric capacity CFB, realize the regulable control to gain level degree, thus postiive gain levelness can be realized, automatic biasing triode Q1 in the auto bias circuit 103 and final stage amplifying triode Q3 in multistage current amplification circuit 101 forms circuit mirror current, auto bias circuit 101 and internal feedback resistance RFB1 come together to arrange reference current Iref, reference current Iref is mirrored and reflexes to final stage amplifying triode Q3.The ratio of mirror reflection depends on the ratio of automatic biasing triode Q1 and final stage amplifying triode Q3, and the resistance of the emitter bias resistance of automatic biasing triode Q1 and the emitter bias resistance of Self-bias Current resistance RE1 and final stage amplifying triode Q3 and final bias current resistance RE3 is also arranged in proportion with mirroring ratios; Circuit radio-frequency performance is depended in the selection of isolation resistance RB2 resistance, and its resistance is between 100 Ω to 10000 Ω usually, and shunt capacitance CB sets the lower bound of circuit running frequency together with isolation resistance RB2.
Described wide-band amplifier is under the acting in conjunction of the anti-road of inside and outside feedback and auto bias circuit, achieve gain reduction and be less than 0.2dB in whole frequency band range, and by regulating the parameter in external feedback circuit, the control to gain level degree can be realized, according to the needs of practical application, can make signal 500 ~ 1000MHz band frequently in gain not anti-reflection increase, realize postiive gain levelness and gain increases along with the increase of frequency, thus greatly extend the application scenario of this wide-band amplifier.
Above the better embodiment of this patent is explained in detail, but this patent is not limited to above-mentioned execution mode, in the ken that one skilled in the relevant art possesses, various change can also be made under the prerequisite not departing from this patent aim.
Claims (2)
1. a wide-band amplifier, is characterized in that: comprise multistage current amplification circuit (101), external feedback circuit (102), auto bias circuit (103) and internal feedback circuit (104), described multistage current amplification circuit (101) comprises first order current amplification circuit and second level current amplification circuit, first order current amplification circuit comprises the elementary amplifying triode Q2 of emitter follower type, the emitter of elementary amplifying triode Q2 is by primary bias current resistor RE2 ground connection, second level current amplification circuit comprises common emitter type final stage amplifying triode Q3, final stage amplifying triode Q3 is by final bias current resistance RE3 ground connection, the base stage of final stage amplifying triode Q3 is connected with electric capacity C1 with the emitter of elementary amplifying triode Q2 respectively, the other end ground connection of electric capacity C1, the base stage of elementary amplifying triode Q2 is as the input of described multistage current amplification circuit (101), the collector electrode of final stage amplifying triode Q3 is connected with the collector electrode of elementary amplifying triode Q2, and as the output of described multistage current amplification circuit (101), the i.e. output of whole wide-band amplifier, described internal feedback circuit (104) comprises internal feedback resistance RFB1, bias voltage resistance RB1 and resistance R1, one end of internal feedback resistance RFB1 is connected with one end of bias voltage resistance RB1, form load point, the other end of internal feedback resistance RFB1 is connected with the output of multistage current amplification circuit (101), the other end of bias voltage resistance RB1 connects the input of wideband amplification circuit, resistance R1 one end connects the input of wideband amplification circuit, and the other end is connected with the input of multistage current amplification circuit (101), described external feedback circuit (102) comprises external feedback resistance RFB2, electric capacity C2, external feedback electric capacity CFB and external feedback inductance L FB, electric capacity C2 is in parallel with external feedback electric capacity CFB, one end of external feedback resistance RFB2 is connected with one end of external feedback electric capacity CFB, the other end of external feedback resistance RFB2 is connected with one end of external feedback inductance L FB, the other end of external feedback electric capacity CFB is connected with the input of wideband amplification circuit, and the other end of external feedback inductance L FB is connected with the output of described multistage current amplification circuit (101), described auto bias circuit (103) comprises shunt capacitance CB and automatic biasing triode Q1, the base stage of automatic biasing triode Q1 is connected with the base stage of final stage amplifying triode Q3 by isolation resistance RB2, the base stage of final stage amplifying triode Q3 is by described shunt capacitance CB ground connection, the emitter of automatic biasing triode Q1 is by Self-bias Current resistance RE1 ground connection, and the collector electrode of automatic biasing triode Q1 is connected with described load point.
2. wide-band amplifier according to claim 1, is characterized in that: described electric capacity C2 is electrochemical capacitor, and external feedback electric capacity CFB is ceramic disc capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510128428.9A CN104753473A (en) | 2015-03-24 | 2015-03-24 | Broadband amplifier |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510128428.9A CN104753473A (en) | 2015-03-24 | 2015-03-24 | Broadband amplifier |
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| CN104753473A true CN104753473A (en) | 2015-07-01 |
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| CN201510128428.9A Pending CN104753473A (en) | 2015-03-24 | 2015-03-24 | Broadband amplifier |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106100593A (en) * | 2015-11-20 | 2016-11-09 | 厦门宇臻集成电路科技有限公司 | A kind of broadband ultra-linear amplifier circuit |
| CN114928336A (en) * | 2022-06-01 | 2022-08-19 | 电子科技大学 | Darlington amplifier with optimized low frequency noise function |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100141339A1 (en) * | 2008-10-17 | 2010-06-10 | Day Chris J | Apparatus and Method for Broadband Amplifier Linearization |
| CN104124931A (en) * | 2014-08-07 | 2014-10-29 | 苏州容芯微电子有限公司 | Broadband amplifier |
-
2015
- 2015-03-24 CN CN201510128428.9A patent/CN104753473A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100141339A1 (en) * | 2008-10-17 | 2010-06-10 | Day Chris J | Apparatus and Method for Broadband Amplifier Linearization |
| CN104124931A (en) * | 2014-08-07 | 2014-10-29 | 苏州容芯微电子有限公司 | Broadband amplifier |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106100593A (en) * | 2015-11-20 | 2016-11-09 | 厦门宇臻集成电路科技有限公司 | A kind of broadband ultra-linear amplifier circuit |
| CN106100593B (en) * | 2015-11-20 | 2019-04-26 | 厦门宇臻集成电路科技有限公司 | A kind of broadband ultra-linear amplifier circuit |
| CN114928336A (en) * | 2022-06-01 | 2022-08-19 | 电子科技大学 | Darlington amplifier with optimized low frequency noise function |
| CN114928336B (en) * | 2022-06-01 | 2023-04-25 | 电子科技大学 | Darlington amplifier with low-frequency noise optimizing function |
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Application publication date: 20150701 |