CN102570985A - Power amplifying circuit for powerline multicarrier communication systems - Google Patents

Abstract

The invention discloses a power amplifying circuit for powerline multicarrier communication systems, which comprises a blocking coupled circuit, a biasing circuit, a main amplifying circuit, a power driving class-AB output stage and a feedback control circuit, wherein the blocking coupled circuit comprises a capacitor C1 and a capacitor C3; the biasing circuit comprises a resistor R1 and a resistor R2; the main amplifying circuit comprises a first-level grounded-emitter amplifying stage and a second-level grounded-emitter amplifying stage; the power driving class-AB output stage comprises a NPN-type triode Q3, a resistor R8, a resistor R9, a PNP-type triode Q4 and a resistor R10 which are sequentially connected in series between a power supply VCC and a ground wire GND; and the feedback control circuit comprises a resistor R4, an adjustable resistor R5 and a capacitor C2. According to the power amplifying circuit, as a class-AB push-pull mode is adopted by the driving stage of the power amplifying circuit, the output efficiency is improved; meanwhile, through using a negative feedback connecting mode, the linearity is improved, and the harmonic distortion is reduced, therefore, the power amplifying circuit disclosed by the invention is suitable for broadband signals and multicarrier systems.

Description

A kind of power amplification circuit that is used for the power line multi-carrier communications systems

Technical field

The invention belongs to electronic technology field, particularly a kind of power amplification circuit that is used for the power line multi-carrier communications systems.

Background technology

Access and the variation that cuts out at random of various power line loads and power equipment caused power line high frequency equiva lent impedance to change from 0.1 Ω to hundreds of Ω on the electrical network, and power line channel characteristic complicated and changeable and abominable electric line carrier communication environment have proposed requirements at the higher level to the power amplification circuit of carrier signal.Structure by the transmitting terminal of power-line carrier communication system shown in Figure 1 can be found out; Digital signal reverts to analog signal to be sent through behind digital to analog converter (DAC) 1 and the low pass filter 2, and this analog passband signal overpower amplifier 3 amplifies after overcoupled circuits 4 are sent on the 220V power line transmits.

In the prior art; Scheme commonly used in the power-line carrier communication system is directly carrier signal to be enlarged into switching signal with the digital power amplifying circuit on power line, to transmit; This method is because harmonic distortion is very big; Be only applicable to single-frequency point carrier signal transmission system, be impractical in broadband signal and multicarrier system.

Summary of the invention

In order to solve the problems referred to above of prior art, the purpose of this invention is to provide a kind of power amplification circuit that is used for the power line multi-carrier communications systems, the harmonic distortion when amplifying to reduce carrier signal makes it be applicable to broadband signal and multicarrier system.

To achieve these goals, the invention provides a kind of power amplification circuit that is used for the power line multi-carrier communications systems, comprise at a distance from straight coupling circuit, biasing circuit, main amplifying circuit, power drive AB class output stage and feedback control circuit, wherein,

Said separated straight coupling circuit comprises capacitor C 1 and capacitor C 3, and capacitor C 1 is connected in the input of said power amplification circuit, and capacitor C 3 is connected in the output of said power amplification circuit;

Said biasing circuit comprises the resistance R 1 and resistance R 2 that is connected between power supply VCC and the ground wire GND;

Said main amplifying circuit comprises first order cascode amplifying stage and second level cascode amplifying stage; Said first order cascode amplifying stage comprises NPN type triode Q1 and resistance R 3; Resistance R 3 is connected between the collector electrode of power supply VCC and triode Q1; The base stage of triode Q1 connects the node of 2 of resistance R 1 and resistance R in the said biasing circuit, and the emitter of triode Q1 connects the node between resistance R 4 and adjustable resistance R5 in the said feedback control circuit; Said second level cascode amplifying stage comprises positive-negative-positive triode Q2, diode D1, adjustable resistance R6 and the resistance R 7 between power supply VCC and ground wire GND in sequential series; The base stage of triode Q2 connects the collector electrode of triode Q1; The emitter of triode Q2 connects power supply VCC, and the collector electrode of triode Q2 connects diode D1;

Said power drive AB class output stage comprises NPN type triode Q3, resistance R 8, resistance R 9, positive-negative-positive triode Q4 and the resistance R 10 between power supply VCC and ground wire GND in sequential series; The base stage of triode Q3 connects the collector electrode of triode Q2; The collector electrode of triode Q3 connects power supply VCC; The emitter of triode Q3 connects resistance R 8; The base stage of triode Q4 connects the node of 7 of adjustable resistance R6 and resistance R in the cascode amplifying stage of the said second level, and the collector electrode of triode Q4 connects resistance R 10, and the emitter of triode Q4 connects resistance R 9;

Said feedback control circuit comprises resistance R 4, adjustable resistance R5 and capacitor C 2, and adjustable resistance R5, resistance R 4 and capacitor C 2 are in sequential series in said power drive AB class output stage between the node and ground wire GND of 9 of resistance R 8 and resistance R.

Compared with prior art; The present invention has following beneficial effect: power amplification circuit of the present invention is because its driving stage adopts AB class push pull mode; Increased delivery efficiency; Improved the linearity through the negative feedback connected mode simultaneously, thereby therefore the harmonic distortion when having reduced to amplify carrier signal be applicable to broadband signal and multicarrier system.

Description of drawings

Fig. 1 is the structured flowchart of the transmitting terminal of power-line carrier communication system.

Fig. 2 is the circuit structure diagram that is used for the power amplification circuit of power line multi-carrier communications systems of the present invention.

Main description of reference numerals:

1, digital to analog converter 2, low pass filter

3, power amplification circuit 4, coupling circuit

31, at a distance from straight coupling circuit 32, biasing circuit

331, first order cascode amplifying stage 332, second level cascode amplifying stage

34, power drive AB class output stage 35, feedback control circuit

Embodiment

Below in conjunction with accompanying drawing specific embodiment of the present invention is elaborated.

As shown in Figure 2, the power amplification circuit that is used for the power line multi-carrier communications systems of the present invention comprises separated straight coupling circuit 31, biasing circuit 32, main amplifying circuit, power drive AB class output stage 34 and feedback control circuit 35, wherein,

Said separated straight coupling circuit 31 comprises two capacitor C 1 and C3, and capacitor C 1 is connected in the input In of said power amplification circuit, and capacitor C 3 is connected in the output Out of said power amplification circuit; The input In of said power amplification circuit receives the analog signal to be sent of low pass filter output, and the output signal of the output Out of said power amplification circuit is coupled on the 220V power line through overcoupled circuits and transmits.

Said biasing circuit 32 comprises the resistance R 1 and resistance R 2 that is connected between power supply VCC and the ground wire GND;

Said main amplifying circuit comprises first order cascode amplifying stage 331 and second level cascode amplifying stage 332; Said first order cascode amplifying stage 331 comprises NPN type triode Q1 and resistance R 3; Resistance R 3 is connected between the collector electrode of power supply VCC and triode Q1; The base stage of triode Q1 connects the node of 2 of resistance R 1 and resistance R in the said biasing circuit 32, and the emitter of triode Q1 connects the node between resistance R 4 and adjustable resistance R5 in the said feedback control circuit 35; Said second level cascode amplifying stage 332 comprises positive-negative-positive triode Q2, diode D1, adjustable resistance R6 and the resistance R 7 between power supply VCC and ground wire GND in sequential series; The base stage of triode Q2 connects the collector electrode of triode Q1; The emitter of triode Q2 connects power supply VCC, and the collector electrode of triode Q2 connects diode D1;

Said power drive AB class output stage 34 comprises NPN type triode Q3, resistance R 8, resistance R 9, positive-negative-positive triode Q4 and the resistance R 10 between power supply VCC and ground wire GND in sequential series; The base stage of triode Q3 connects the collector electrode of triode Q2; The collector electrode of triode Q3 connects power supply VCC; The emitter of triode Q3 connects resistance R 8; The base stage of triode Q4 connects the node of 7 of adjustable resistance R6 and resistance R in the cascode amplifying stage 332 of the said second level, and the collector electrode of triode Q4 connects resistance R 10, and the emitter of triode Q4 connects resistance R 9;

Said feedback control circuit 35 comprises resistance R 4, adjustable resistance R5 and capacitor C 2, and adjustable resistance R5, resistance R 4 and capacitor C 2 are in sequential series in said power drive AB class output stage 34 between the node and ground wire GND of 9 of resistance R 8 and resistance R.

The closed loop gain A that is used for the power amplification circuit of power line multi-carrier communications systems of the present invention is:

$A=1+\frac{R5}{R4+\frac{1}{\mathrm{<figure-callout\; id="2"\; label="SC"\; filenames="HDA0000128065290000011.png"\; state="\{\{state\}\}">SC</figure-callout>}2}}=1+\frac{\mathrm{j\&omega;}.R5.\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="HDA0000128065290000011.png"\; state="\{\{state\}\}">C</figure-callout>}2}{1+\mathrm{j\&omega;}.\mathrm{<figure-callout\; id="4"\; label="R"\; filenames="HDA0000128065290000011.png"\; state="\{\{state\}\}">R</figure-callout>}4.C2}---\left(1\right)$

Can find out that by formula (1) the closed loop gain A of power amplification circuit of the present invention is directly proportional with the resistance of adjustable resistance R5, can regulate closed loop gain A, make A=3～4 usually through the resistance of regulating adjustable resistance R5.

Adjustable resistance R6 is used to regulate the quiescent bias current of said power drive AB class output stage 34; If the quiescent bias current of said power drive AB class output stage 34 too conference causes energy transmission efficiency to descend; If too little meeting causes more serious intermodulation distortion and can not drive very heavy load, therefore, adjustable resistance R6 selects suitable resistance value very important to power amplifier performance parameter; In the present embodiment, the quiescent bias current of said power drive AB class output stage 34 is 20mA.

Resistance R 10 is used to detect the power of said power drive AB class output stage 34, and in the present embodiment, as preferred embodiment, its resistance is 1 Ω; Capacitor C 2 constitutes the single order high pass filter with resistance R 4, and it has inhibitory action to low-frequency noise, and in the present embodiment, as preferred embodiment, capacitor C 2 is arranged on 100KHz with the cut-off frequency of the single order high pass filter of resistance R 4; Can know that according to formula (1) gain of signal is confirmed by the ratio of adjustable resistance R5 and resistance R 4 in passband; Triode Q3 and triode Q4 are the high-power driving triodes, and the maximum current that allows to pass through is 3A.

Power amplification circuit of the present invention is used for that the analog signal of the transmitting terminal of power line multi-carrier communications systems is amplified back being coupled on the power line through coupling circuit to be transmitted; Because its driving stage adopts AB class push pull mode; Increased delivery efficiency; Improved the linearity through the negative feedback connected mode simultaneously, thereby therefore the harmonic distortion when having reduced to amplify carrier signal be applicable to broadband signal and multicarrier system.

Above embodiment is merely exemplary embodiment of the present invention, is not used in restriction the present invention, and protection scope of the present invention is defined by the claims.Those skilled in the art can make various modifications or be equal to replacement the present invention in essence of the present invention and protection range, this modification or be equal to replacement and also should be regarded as dropping in protection scope of the present invention.

Claims (1)

1. a power amplification circuit that is used for the power line multi-carrier communications systems is characterized in that, said power amplification circuit comprises separated straight coupling circuit, biasing circuit, main amplifying circuit, power drive AB class output stage and feedback control circuit, wherein,

Said separated straight coupling circuit comprises capacitor C 1 and capacitor C 3, and capacitor C 1 is connected in the input of said power amplification circuit, and capacitor C 3 is connected in the output of said power amplification circuit;

Said biasing circuit comprises the resistance R 1 and resistance R 2 that is connected between power supply VCC and the ground wire GND;

Said main amplifying circuit comprises first order cascode amplifying stage and second level cascode amplifying stage; Said first order cascode amplifying stage comprises NPN type triode Q1 and resistance R 3; Resistance R 3 is connected between the collector electrode of power supply VCC and triode Q1; The base stage of triode Q1 connects the node of 2 of resistance R 1 and resistance R in the said biasing circuit, and the emitter of triode Q1 connects the node between resistance R 4 and adjustable resistance R5 in the said feedback control circuit; Said second level cascode amplifying stage comprises positive-negative-positive triode Q2, diode D1, adjustable resistance R6 and the resistance R 7 between power supply VCC and ground wire GND in sequential series; The base stage of triode Q2 connects the collector electrode of triode Q1; The emitter of triode Q2 connects power supply VCC, and the collector electrode of triode Q2 connects diode D1;

Said power drive AB class output stage comprises NPN type triode Q3, resistance R 8, resistance R 9, positive-negative-positive triode Q4 and the resistance R 10 between power supply VCC and ground wire GND in sequential series; The base stage of triode Q3 connects the collector electrode of triode Q2; The collector electrode of triode Q3 connects power supply VCC; The emitter of triode Q3 connects resistance R 8; The base stage of triode Q4 connects the node of 7 of adjustable resistance R6 and resistance R in the cascode amplifying stage of the said second level, and the collector electrode of triode Q4 connects resistance R 10, and the emitter of triode Q4 connects resistance R 9;

Said feedback control circuit comprises resistance R 4, adjustable resistance R5 and capacitor C 2, and adjustable resistance R5, resistance R 4 and capacitor C 2 are in sequential series in said power drive AB class output stage between the node and ground wire GND of 9 of resistance R 8 and resistance R.

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