CN2109662U

CN2109662U - Pre-set working state audio frequency power amplifier

Info

Publication number: CN2109662U
Application number: CN 91228050
Authority: CN
Inventors: 耿纯
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-11-12
Filing date: 1991-11-12
Publication date: 1992-07-08

Abstract

The utility model relates to a pre-set working state audio frequency power amplifier, which is an audio frequency power amplifier to pre-set the operating condition and the converting efficiency of the amplifier according to the requirement of sound amplification. The amplifier is matched with a high speed regulated power supply to make the operation of the power amplifier stable and reliable, and the amplifier thoroughly overcomes the parasitic compression and parasitic expansion in the amplifying process resulting from the unsteady power supply voltage to make the replayed sound more true.

Description

Pre-set working state audio frequency power amplifier

The utility model is the audio-frequency power amplifier that a kind of operating state can preset.

Because the operating state difference of audio-frequency power amplifier, the power output that can provide, conversion efficiency and tone color are also different.Generally before dispatching from the factory, the operating state adjustment of power amplifier has been fixed; Make power amplifier just significantly reduce, limited the use flexibility of power amplifier for the adaptability of tone color, conversion efficiency.

The purpose of this utility model provides the audio-frequency power amplifier that a kind of operating state can preset; Make power amplifier have bigger use flexibility at aspects such as power output, conversion efficiency and tone colors.

The purpose of this utility model is achieved in that and is provided with signal input, feedback circuit, constant-current source circuit, voltage amplifier circuit in can presetting the operating state audio-frequency power amplifier, output bias circuit, power amplifier output circuit, operating state preset, display circuit, the high-speed voltage stabilization power circuit.Below in conjunction with drawings and Examples the utility model is further described.

Fig. 1. be the utility model main amplifier circuit figure.

Fig. 2. be that operating state presets, display circuit figure.

Fig. 3. be the high-speed voltage stabilization power circuit diagram.

At Fig. 1. in, signal input, feedback circuit 1 are made up of T1, T2, R1, R2, R4, R13, C1.Transistor T 1, T2 form differential amplifier circuit.R1 one termination T1 manages base stage, and other end ground connection is for the T1 pipe provides direct current biasing.Signal is by the input of T1 pipe base stage, and R2 is the collector load resistor of T1 pipe, and its effect is to provide Dc bias and audio output signal for voltage amplifying tube T5.One termination T2 base stage of resistance R 13, the other end is connected with source electrode tie point, the power take-off of power output tube T8, T9, constitutes feedback, path.The positive termination T2 base stage of C1, negative terminal meets R4, the other end ground connection of R4.In exchanging feedback network, feedback signal is carried out dividing potential drop by R13, R4, to reach with predetermined voltage gain; In the DC feedback path because C1 stopping direct current effect over the ground, R4 not with the R13 dividing potential drop, constitute 100% direct current negative feedback, further the dc point of stabilizing circuit.Constant-current source circuit is made up of T3, T4, T7, R3, R5, R6.The emitter of the collector electrode of T3 pipe by T1, T2 pipe is connected with+Ec, and R3 is the emitter resistance of T3 pipe, and T4 pipe emission collection connects-Ec, and base stage connects T3 pipe emitter; Collector electrode connects T3 pipe base stage, and R5 provides operating current for the T4 pipe.As long as transistorized base potential is stable, output current is just stable.The stabilization process of T3 pipe base voltage is as follows: establishes T3 pipe base potential and rises, and T3Ube ↑ → T3Ib ↑ → T3Ie ↑ → UR3 ↑ → T4Ube ↑ → T4Ib ↑ → T4Ic ↑ → UR5 ↓ → the T3 base potential is stable.Set the resistance of R3, just can set the constant operating current of T1T2.The T7 pipe limit utmost point is connected on the tie point of T3b and T4c.Because the stable operating voltage of T3b, the operating voltage of T7b are also stable, set the resistance of R6, just can be the T5 pipe constant operating current is provided.Voltage amplifier circuit 3 is made up of T5, T6, T7, R6.Directly enter the T5 base stage by the audio signal of T1 pipe collector output and carry out voltage amplification, set the R2 resistance, just provide Dc bias for the T5 pipe.T5 pipe emitter connects+Ec, and collector electrode connects T7 pipe constant-current source through T6 collector electrode, emission collection.Set the R6 resistance, just can set the constant operating current of T5 pipe.The voltage signal one tunnel of T5 pipe collector output is through the grid of R11 ingoing power amplifier tube T8, and another road enters the grid of power tube T9 through T6 collector electrode, emitter, R12.Output bias circuit 4 is made up of T6, R7, R8, R9, R10.The T6 collector electrode connects the T5 collector electrode, T6 emission collection connects the T7 pipe collector, and the effect of T6 is constant current path and the signal path that is communicated with T5T7, by setting the numerical value of R7, R8, decide the collector electrode of T6, the voltage at emitter two ends, i.e. the bias voltage of T8, T9 power tube.R7 is connected across between T6 collector electrode, the base stage, and R8 is connected across between T6 base stage, the emitter.The termination T6 base stage of R9, another termination b; The termination T6 base stage of R10, another termination a; The emitter of T6 meets c.Power amplifier output circuit 5 is made up of T8, T9, DW1, DW2, R11, R12, R14, C2, C3, C4, L.T8, T9 are the high complementary V-MOS pipes of a pair of switching rate.The positive signal of T5 collector electrode output enters the T8 grid through R11 amplifies, and the negative signal of T5 output enters the T9 grid from T6 collector electrode, emitter, R12 and amplifies.DW1 one termination R11, another termination T8 source electrode carry out limited amplitude protection to the grid potential of T8.The termination R12 of DW2, another termination T9 source electrode carries out limited amplitude protection to the grid potential of T9.R11, R12 are the vibrationproof resistance of T8, T9.Positive and negative audio signal after T8, T9 amplify is in the synthetic complete audio signal of an end of inductance L, and through L output, the other end of L is connected to the high-frequency resistance balancing circuitry of loud speaker and C2, R14 composition.The effect of L is to prevent that circuit from producing the superaudio vibration.C3C4 is the filter capacitor of positive and negative power supply.Operating state presets, display circuit 6(Fig. 2) form by operating state initialize switch K1, J1, J2, LED1, LED2, R15R16.The process that operating state presets is such.In main amplifier (Fig. 1),, power amplifier is set in the category-B operating state by adjusting the ratio of R7, R8.The B of this moment show LED2 one end through normally closed some 2-3 of J2, movable contact 2-2 connect+the EC other end is through current-limiting resistance R16 ground connection, LED2 is luminous.When K1 puts the AB operating state, J1 coil one end ground connection, the other end through K1 and+EC connect, the relay adhesive.A shows LED1 one end through R15 current-limiting resistance ground connection, and the other end is connected with+EC through 1-1 normally opened contact, 1-2 moving contact, and A shows that LED1 is luminous.LED2 continues luminous, carries out the AB state and shows.Another group normally opened contact of J1 1-4 is connected with (Fig. 1) C point, and moving contact 1-5 is connected with (Fig. 1) a point, and under the adhesive effect of relay, 1-4,1-5 connect, and resistance R 10a end is logical with the C termination, is connected in parallel on the R8.Set the R10 resistance, make main amplifier be operated in the AB state.When K1 left the AB contact, J1 resetted, and A shows that LED1 extinguishes, and R10a point and C point disconnect.When K1 puts the A operating state, J2 coil one end ground connection, the other end is connected the relay adhesive through K1 with+EC.This moment, A showed that LED1 connects, lights with+EC through often make war 2-1, moving contact 2-2 of J2.B show the frequent close point 2-3 of LED2,2-2 connect+power supply of EC is cut off, B shows and extinguishes.Another organizes J2 normal battle 2-4 and links to each other with (Fig. 1) C, and moving contact 2-5 links to each other with (Fig. 1) b.Under the adhesive effect of relay, the R9b end is connected with C, is connected in parallel on the R8, sets the numerical value of R9, makes main amplifier be operated in the category-A state.When K1 left the A position, J2 resetted, and A shows that LED1 extinguishes, and B shows that LED2 lights, and b, c point disconnects among Fig. 1, and main amplifier is not arranged on the A operating state.High-speed voltage stabilization power circuit 7(Fig. 3), by power transformer B1, rectifier diode D1-D4, Ic1, Ic2, T10, T11, DW3, DW4, R18, R19, R20, R21R22, C5, C6, C7, C8, C9, C10 form.C5, C6 are the filter capacitors of positive supply, DW3 one end ground connection, and R17 provides operating current for DW3, and power adjustment pipe T10 adopts the high V-MOS pipe of switching speed, T10 drain electrode to connect the C5 positive pole, and source electrode is+the EC output.The Ic1 open loop is used, and is connected into voltage comparator, and R18R19 is the sampling divider resistance, be serially connected in+EC and ground between.On the tie point of Ic1 positive input termination DW3 and R17, obtain reference voltage, the Ic1 negative input end connects on the tie point of R18R19, input sampling voltage, Ic1 output termination T10 grid.T10 is a N type V-MOS pipe.Its voltage stabilizing process is as follows :+EC ↓ → UR19 ↓ → UIc1 ↑ → T10Ug ↑ → T10IDS ↑ →+EC ↑.C7 is+the EC output filter capacitor.Because Ic1 open-loop gain height, T10 switching speed height, so stabilized voltage power supply regulating the speed under big current work state, the precision of voltage regulation are also high.By Ic2, T11, DW4, C8, C9, C10, R20, R21, R22 formed-Ec power work principle is with+EC.In the power amplifier of brute supply power supply,, under the situation of power-supply fluctuation, cause the parasitism compression or the parasitic expansion of amplification quantity because amplifying circuit is non-linear.The audio-frequency power amplifier of employing high-speed voltage stabilization power supply can thoroughly overcome the parasitism expansion of general category-A machine greatly dynamically the time and thoroughly overcome the parasitism compression of general category-B machine when dynamic greatly, makes the replay signal more accurate, truer.

Claims

1, a kind of operating state audio-frequency power amplifier that presets is characterized in that being provided with signal input, the feedback circuit be made up of T1, T2, R1, R2, R4, R13, C1; Managing emitter with input, feedback circuit T1, T2 for one is connected, the constant-current source circuit of forming by T3, T4, T7, R3, R5, R6 that is connected with output bias circuit T6 pipe emitter, one be connected with input, feedback circuit T1 pipe collector manage the voltage amplifier circuit of forming by T5; One be connected with voltage amplifier circuit T5 pipe collector by output bias circuit that T6, R7, R8, R9, R10 formed; One be connected with output bias circuit R7, R8 by power amplifier output circuit that T8, T9, DW1, DW2, R11R12, R14, C2, C3, C4, L formed; The operating state by K1, J1, J2, LED1, LED2, R15, R16 formed that is connected with output bias circuit a, b, c point presets display circuit; One with+EC ,-EC, earth point be connected by high-speed voltage stabilization power circuit that B1, D1-D4, IC1, IC2, T10, T11, DW3, DW4, R18-R22, C5-C10 formed.

2, the operating state audio-frequency power amplifier that presets according to claim 1 is characterized in that operating state presets operating state prewired circuit that display circuit is made up of K switch 1, relay J 1J2 and is made up of operating state display circuit two parts that LED1, LED2, R15, R16 form; J1 moving contact 1-5 is connected with a point in the output bias circuit; The moving contact 2-5 of J2 is connected with b point in the output bias circuit; The tie point of normally opened contact 1-4, the 2-4 of J1, J2 is connected with c point in the output bias circuit.

3, the operating state audio-frequency power amplifier that presets according to claim 1 is characterized in that the high-speed voltage stabilization power circuit is made up of transformation, rectification, filtering and voltage stabilizing circuit; N type V-MOS power adjustment pipe drain electrode connects the C5 positive pole, and source electrode is+the EC output stage, and IC1, DW3, R17, R18, R19 form voltage comparator, and the IC1 output is connected with the T10 tube grid, forms positive stabilized voltage power supply; P type V-MOS power adjustment pipe T11 drain electrode connects capacitor C 8 negative poles, and source electrode be-the EC output stage, and IC2, DW4, R20, R21, R22 form voltage comparator, and the IC2 output is connected with the T11 tube grid, and composition is born stabilized voltage power supply.The tie point of capacitor C 5 negative poles and capacitor C 8 positive poles is an earth point.