CN104283515A - Power amplification circuit - Google Patents
Power amplification circuit Download PDFInfo
- Publication number
- CN104283515A CN104283515A CN201410584806.XA CN201410584806A CN104283515A CN 104283515 A CN104283515 A CN 104283515A CN 201410584806 A CN201410584806 A CN 201410584806A CN 104283515 A CN104283515 A CN 104283515A
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- resistance
- triode
- amplification circuit
- power amplification
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
- H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03F—AMPLIFIERS
- H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
- H03F2203/20—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers
- H03F2203/21—Indexing scheme relating to power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Amplifiers (AREA)
Abstract
The invention provides a power amplification circuit, solving the problems of an existing power amplification circuit that the structure is relatively complicated, the size is relatively large and the extreme miniaturization is difficult to realize. The power amplification circuit comprises a triode T1, a triode T2, an NPN type composite tube composed of an NPN triode T3 and an NPN triode T4, and a PNP type composite tube composed of a PNP triode T5 and an NPN triode T6, wherein the collector electrode of the triode T1 is connected with a power supply VCC by a resistor R4, an adjustable resistor VR2 and a resistor R3; a connection node between the adjustable resistor VR2 and the resistor R4 is connected with the base electrode of the triode T2; the collector electrode of the triode T2 is connected with a connection node between the resistor R3 and the adjustable resistor VR2 and the base electrode of the NPN type composite tube; the emission electrode of the triode T2 is connected with the collector electrode of the triode T1 and the base electrode of the PNP type composite tube; and the emission electrode of the NPN type composite tube is connected with the emission electrode of the PNP type composite tube by a resistor R7 and a resistor R8. The power amplification circuit has a simple structure and can meet the requirement on extreme miniaturization; and the stability and the reliability are also guaranteed.
Description
Technical field
The present invention is a kind of power amplification circuit.
Background technology
A lot of electronic product is all tending towards miniaturized in daily life, so that carry with.This media player of such as walkman, along with the development and progress of electronic technology, volume becomes more and more less, and the kind of differentiation is a lot, comprises the kinds such as CD, MD, MP3, MP4.And the player of these kinds has a common feature, need exactly to amplify small-signals such as audio frequency.So necessarily all can comprise power amplification circuit on their core circuit plate, therefore the scale of power amplification circuit directly will affect the size of circuit board, and then the size of restriction playback equipment.Although it is the smaller the better that most people all wishes that walkman does.But simultaneously or the characteristic dimensions of amplifier must be held in a higher level.After all we to performance requirements such as the tonequality of a player than higher to the requirement of volume, so the performance of player can not be reduced in order to reduce volume.Like this, between the scale (miniaturization) and performance of power amplification circuit, there is optimization problem.Existing power amplification circuit is while maintenance characteristic, and structure relative complex, volume is relatively large, is difficult to extremely miniaturized.
Summary of the invention
The present invention solves existing power amplification circuit while maintenance feature, structure relative complex, and volume is relatively large, is difficult to extremely miniaturized problem, provides a kind of power amplification circuit.The structural design of this power amplification circuit is enough simple, meets extremely miniaturized requirement, but in turn ensure that its stability and reliability.
The present invention adopts following technical scheme to realize: power amplification circuit, comprises triode T1, triode T2, the NPN type multiple tube be made up of NPN triode T3 and NPN triode T4, the positive-negative-positive multiple tube be made up of PNP triode T5 and NPN triode T6, resistance R1 is had between power supply VCC and ground, the bleeder circuit that resistance R2 conspires to create, connected node between resistance R1 and resistance R2 is connected with the base stage of triode T1, be connected with the adjustable side of adjustable resistance VR1 through electric capacity C1 simultaneously, one end ground connection of adjustable resistance VR1, the other end is as the signal input part of power amplification circuit, the emitter of triode T1 is through resistance R5, resistance R6 ground connection, the two ends of resistance R6 are parallel with electric capacity C3, the collector electrode of triode T1 is through resistance R4, adjustable resistance VR2 and resistance R3 meets power supply VCC, electric capacity C2 is connected with between the collector electrode of the connected node between resistance R3 and adjustable resistance VR2 and triode T1, connected node between adjustable resistance VR2 and resistance R4 is connected with the base stage of triode T2, the collector electrode of triode T2 is connected with the base stage of the connected node between resistance R3 and adjustable resistance VR2 and NPN type multiple tube, the emitter of triode T2 is connected with the base stage of the collector electrode of triode T1 and positive-negative-positive multiple tube, the collector electrode of NPN type multiple tube is connected with power supply VCC, the emitter of NPN type multiple tube is through resistance R7, resistance R8 is connected with the emitter of positive-negative-positive multiple tube, the grounded collector of positive-negative-positive multiple tube, connected node between resistance R7 and resistance R8 is through electric capacity C4, resistance R9 ground connection, and wherein the voltage at resistance R9 two ends is the output of power amplification circuit, for driving load, electric capacity C5 is connected with between power supply VCC and ground.
Resistance R5 and R6 is mainly in order to provide a suitable current potential to the emitter of T1.Because if current potential too higher position can not obtain large collector electrode amplitude, and too low, the change of temperature can increase again the impact of collector current.So arrange a suitable emitter current potential by these two resistance.Being connected across R6 two ends with C3 is alternating voltage multiplication factors in order to increasing circuit.
R1 and R2 decides the base potential of T1, and the emitter current potential just now set adds V
bEjust obtain base potential.The resistance of R1 and R2 to select large a bit, make the input resistance of amplifying circuit enough large.C1 is the coupling capacitance of input, and it can form high pass filter with input impedance, decides the cut-off frequency of circuit.VR1 is the variable resistor of adjustment incoming level, can be used to the volume regulating walkman.
Between the collector electrode that this circuit has been connected on the biasing circuit of emitter follower the triode T1 of grounded emitter circuit and resistance R3.The electric current that this circuit flows through at VR2 and R4 branch road is determined by R4, and its current value is V
bE/ R4.So the collector current of T2 deducts the electric current flow through at VR2 and R4 branch road with regard to the collector current equaling T1.
The effect of triode T2 is for output stage below provides an appropriate bias current, thus reduces intermodulation distortion.Principle is as follows: establish 4 pipes to be all silicon materials pipe below.T3, T4 compound is also equivalent to a NPN pipe, then its emitter junction needs 1.2V forward bias voltage (establishing a PN junction to want 0.6V voltage), and T5, T6 compound is below equivalent to a PNP pipe, its emitter junction needs 0.6V voltage, so, 1.8V voltage (on just lower negative) will be had by the base stage of upper pipe to the base stage of lower pipe.That is, as long as it is that 1.8V voltage just can reach requirement to emitter that T2 above manages collector electrode.And this voltage just equals the collector potential that power supply VCC deducts pressure drop on R3 and T1, the pressure drop on R3 equals the collector current of R3*T2; Flow through collector electrode, emitter current all approximately equals of the collector electrode of the electric current of R3 and T2, emitter current and T1, and be determined by the ratio of VR2 and R4, VR2, R4 can regard the upper and lower biasing resistor of T2 as, and suitably adjustment just can change the collector current of T2.Obviously: when VR2 reduces, the collector current of T2 increases, and the pressure drop on R3 increases, the collector potential of T1 raises (namely the emitter current potential of T2 raises), so the pressure drop between C, E of T2 reduces, the electric current of output stage diminishes, and now likely occurs intermodulation distortion; Otherwise then intermodulation distortion diminishes or disappears.C2 carries out bypass to biasing circuit, is to make the impedance " seen " by the base stage of T3 and T5 equal.Due to the insertion of C2, high frequency distortion rate improves.C2 value is larger, and the impedance between the base stage of T3 and the base stage of T5 is lower, but too large also meaningless, and desirable C2=3.3 μ F as a reference here.
Emitter resistance R7 and R8 of T4 and T5 plays restriction output current, absorbs the V of T3, T4, T5 and T6
bEbe worth temperature variant effect.But as this circuit, emitter resistance value hour, can not be absorbed with too high expectation to variations in temperature.The value of R7 and R8 obtains excessive, then because of the cause that load current flows at R7 and R8, this resistance can produce larger power loss.Therefore, this emitter resistance is set in the value less than connect load resistance, namely less than 1/10.For the loud speaker that load is common, impedance is probably 8 Ω, so get R7=R8=0.5 Ω (now power and voltage amplification degree have the loss of 3%).
C4 is used to the coupling capacitance of isolated direct current.C4 and load constitute high pass circuit, so can have an impact to circuit when low-frequency voltage signal effect.When not connecing load, R9 is the resistance (be after being powered up, even if connect loud speaker, also do not send vibrations noise) that C4 is discharged.Excessive value is nonsensical, too littlely again power loss occurs, and is taken as R9=lk Ω here.C5 is the decoupling capacitor of power supply.In the single power consumption amplifier that this circuit is such, the collector electrode side (i.e. power supply) of the T3 seen by the GND (i.e. OV) of output is low-down with the impedance of the emitter side of T6 under the frequency outputed signal.When output current flows in a large number, will there is distortion in output waveform.The emitter (i.e. the collector electrode of positive-negative-positive multiple tube) of T6 meets GND, and the impedance for GND is O.But the collector electrode of T3 connects power supply, therefore certain resistance must be had.Therefore, the value of C5 is obtained enough large, to reduce the low-frequency impedance to GND.
The circuit of the present invention's design is equivalent to the main amplifier section of audio frequency amplifier.The place of adjustment, be only the biased VR2 of emitter follower, output level VR1 adjusts.As being used on walkman, be enough good.This circuit amplifies with the voltage of total radio amplifier to input signal.Biasing circuit is connected on the collector electrode of total radio amplifier, and produces the bias voltage of emitter follower, finally carries out Current amplifier by accurate complementary output level.Why adopt quasi-complementary circuit in output stage, be because output resistance can be made less like this, carrying load ability strengthens, and maximum nondistortion output voltage is large, and its amplitude can close to supply voltage.Meanwhile, multiple tube is adopted can also to increase the current amplification factor of T3 pipe and T5 pipe, to reduce prime drive current like this.And NPN type and the positive-negative-positive pipe of finding characteristic full symmetric are more difficult, so T3, T4 are composited a NPN type pipe in this circuit, T5, T6 are composited a positive-negative-positive pipe.Enter viewed from output, T4 pipe, T6 pipe all have employed pipe of the same type, are easier to accomplish that characteristic is identical.
The reasonable in design of power amplification circuit of the present invention, enough simple, meet extremely miniaturized requirement, but in turn ensure that its stability run and reliability.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of power amplification circuit of the present invention.
Embodiment
Power amplification circuit, comprises triode T1, triode T2, the NPN type multiple tube be made up of NPN triode T3 and NPN triode T4, the positive-negative-positive multiple tube be made up of PNP triode T5 and NPN triode T6, resistance R1 is had between power supply VCC and ground, the bleeder circuit that resistance R2 conspires to create, connected node between resistance R1 and resistance R2 is connected with the base stage of triode T1, be connected with the adjustable side of adjustable resistance VR1 through electric capacity C1 simultaneously, one end ground connection of adjustable resistance VR1, the other end is as the signal input part of power amplification circuit, the emitter of triode T1 is through resistance R5, resistance R6 ground connection, the two ends of resistance R6 are parallel with electric capacity C3, the collector electrode of triode T1 is through resistance R4, adjustable resistance VR2 and resistance R3 meets power supply VCC, electric capacity C2 is connected with between the collector electrode of the connected node between resistance R3 and adjustable resistance VR2 and triode T1, connected node between adjustable resistance VR2 and resistance R4 is connected with the base stage of triode T2, the collector electrode of triode T2 is connected with the base stage of the connected node between resistance R3 and adjustable resistance VR2 and NPN type multiple tube, the emitter of triode T2 is connected with the base stage of the collector electrode of triode T1 and positive-negative-positive multiple tube, the collector electrode of NPN type multiple tube is connected with power supply VCC, the emitter of NPN type multiple tube is through resistance R7, resistance R8 is connected with the emitter of positive-negative-positive multiple tube, the grounded collector of positive-negative-positive multiple tube, connected node between resistance R7 and resistance R8 is through electric capacity C4, resistance R9 ground connection, and wherein the voltage at resistance R9 two ends is the output of power amplification circuit, for driving load, electric capacity C5 is connected with between power supply VCC and ground.During concrete enforcement, the value of resistance R7, resistance R8 connects by this power amplification circuit less than 1/10 of the resistance value of load.For the loud speaker that load is common, impedance is 8 Ω, so the value of power taking resistance R7, resistance R8 is 0.5 Ω.The value of electric capacity C2 is 3.3 μ F.The value of resistance R9 is lk Ω.
Claims (4)
1. a power amplification circuit, is characterized in that, comprises triode T1, triode T2, the NPN type multiple tube be made up of NPN triode T3 and NPN triode T4, the positive-negative-positive multiple tube be made up of PNP triode T5 and NPN triode T6, resistance R1 is had between power supply VCC and ground, the bleeder circuit that resistance R2 conspires to create, connected node between resistance R1 and resistance R2 is connected with the base stage of triode T1, be connected with the adjustable side of adjustable resistance VR1 through electric capacity C1 simultaneously, one end ground connection of adjustable resistance VR1, the other end is as the signal input part of power amplification circuit, the emitter of triode T1 is through resistance R5, resistance R6 ground connection, the two ends of resistance R6 are parallel with electric capacity C3, the collector electrode of triode T1 is through resistance R4, adjustable resistance VR2 and resistance R3 meets power supply VCC, electric capacity C2 is connected with between the collector electrode of the connected node between resistance R3 and adjustable resistance VR2 and triode T1, connected node between adjustable resistance VR2 and resistance R4 is connected with the base stage of triode T2, the collector electrode of triode T2 is connected with the base stage of the connected node between resistance R3 and adjustable resistance VR2 and NPN type multiple tube, the emitter of triode T2 is connected with the base stage of the collector electrode of triode T1 and positive-negative-positive multiple tube, the collector electrode of NPN type multiple tube is connected with power supply VCC, the emitter of NPN type multiple tube is through resistance R7, resistance R8 is connected with the emitter of positive-negative-positive multiple tube, the grounded collector of positive-negative-positive multiple tube, connected node between resistance R7 and resistance R8 is through electric capacity C4, resistance R9 ground connection, and wherein the voltage at resistance R9 two ends is the output of power amplification circuit, for driving load, electric capacity C5 is connected with between power supply VCC and ground.
2. power amplification circuit according to claim 1, it is characterized in that the value of resistance R7, resistance R8 connect by this power amplification circuit less than 1/10 of the resistance value of load.
3. power amplification circuit according to claim 2, it is characterized in that this power amplification circuit connect load resistance value be 8 Ω, the value of resistance R7, resistance R8 is 0.5 Ω.
4. the power amplification circuit according to claim 1 or 2 or 3, is characterized in that the value of electric capacity C2 is 3.3 μ F; The value of resistance R9 is lk Ω.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410584806.XA CN104283515A (en) | 2014-10-28 | 2014-10-28 | Power amplification circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410584806.XA CN104283515A (en) | 2014-10-28 | 2014-10-28 | Power amplification circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104283515A true CN104283515A (en) | 2015-01-14 |
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ID=52258074
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410584806.XA Pending CN104283515A (en) | 2014-10-28 | 2014-10-28 | Power amplification circuit |
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| CN (1) | CN104283515A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105024660A (en) * | 2015-06-05 | 2015-11-04 | 苏州经贸职业技术学院 | Power amplifier circuit with novel structure |
| CN105187986A (en) * | 2015-07-16 | 2015-12-23 | 苏州欧可罗电子科技有限公司 | Wireless speaker based on WiFi and power amplifier circuit |
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|---|---|---|---|---|
| CN101499779A (en) * | 2009-01-14 | 2009-08-05 | 南京航空航天大学 | Piezoelectric minimized wide-band power amplifier |
| CN102664596A (en) * | 2012-05-08 | 2012-09-12 | 侯德亮 | High fidelity transistor audio power amplifying device |
| CN103248326A (en) * | 2013-04-19 | 2013-08-14 | 广州市迪士普音响科技有限公司 | Output stage circuit of power amplifier |
-
2014
- 2014-10-28 CN CN201410584806.XA patent/CN104283515A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101499779A (en) * | 2009-01-14 | 2009-08-05 | 南京航空航天大学 | Piezoelectric minimized wide-band power amplifier |
| CN102664596A (en) * | 2012-05-08 | 2012-09-12 | 侯德亮 | High fidelity transistor audio power amplifying device |
| CN103248326A (en) * | 2013-04-19 | 2013-08-14 | 广州市迪士普音响科技有限公司 | Output stage circuit of power amplifier |
Non-Patent Citations (2)
| Title |
|---|
| 华成英等: "《模拟电子技术基础（第四版）》", 31 May 2006 * |
| 误会菩提尊者: "功率放大电路", 《百度文库》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105024660A (en) * | 2015-06-05 | 2015-11-04 | 苏州经贸职业技术学院 | Power amplifier circuit with novel structure |
| CN105024660B (en) * | 2015-06-05 | 2018-01-05 | 苏州经贸职业技术学院 | A kind of novel power amplifier circuit of structure |
| CN105187986A (en) * | 2015-07-16 | 2015-12-23 | 苏州欧可罗电子科技有限公司 | Wireless speaker based on WiFi and power amplifier circuit |
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Application publication date: 20150114 |
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| RJ01 | Rejection of invention patent application after publication |