Audio amplifier circuit with filter function
Technical field
The utility model relates to a kind of amplifying circuit, specifically, relates to a kind of audio amplifier circuit with filter function.
Background technology
As everyone knows, loud speaker is device very important in the communication technology, in order to improve the audio of loud speaker, often need to connect in addition comparatively complicated filter, in the time of can causing like this use, overall volume is larger, and cost is higher, is unfavorable for some mini-plant uses cheaply.
The utility model content
The purpose of this utility model is to provide a kind of audio amplifier circuit with filter function, mainly solves the loud speaker cost performance existed in prior art not high, is unfavorable for the problem of some mini-plant uses cheaply.
To achieve these goals, the technical solution adopted in the utility model is as follows:
Audio amplifier circuit with filter function, comprise the audio signal sample circuit, inverting input is connected with the output of audio signal sample circuit by resistance R 4, and the operational amplifier T1 that output is connected with the output of audio signal sample circuit by diode D1, and the filter circuit be connected with the inverting input of operational amplifier T1, the signal amplification circuit that input is connected with filter circuit, the output of described operational amplifier T1 is connected by diode D2 with inverting input, described filter circuit comprises the resistance R 8 that in-phase input end passes through to be connected successively, resistance R 6, capacitor C 2, the operational amplifier T2 that resistance R 5 is connected with the inverting input of operational amplifier T1, be connected in in-phase input end and the capacitor C between ground 4 of operational amplifier T2, one end is connected between capacitor C 2 and resistance R 6, the resistance R 7 of other end ground connection, one end is connected between resistance R 6 and resistance R 8, the other end is connected in the capacitor C 3 of the output of operational amplifier T2, described signal amplification circuit comprises the triode Q3 that base stage is connected with the output of operational amplifier T2, the operational amplifier T3 that in-phase input end is connected with the emitter of triode Q3 by electrochemical capacitor C5, be connected in inverting input and the capacitor C between output 6 of operational amplifier T3, after series connection, be parallel to capacitor C 7 and the resistance R 13 at capacitor C 6 two ends.
Specifically, described audio signal sample circuit comprises triode Q1, the triode Q2 that base stage is connected with the collector electrode of triode Q1, between the collector electrode that is connected in triode Q2 and ground and capacitor C 1 and the resistance R 3 of mutually connecting, be connected in the base stage of triode Q1 and the buzzing sheet U between ground, described resistance R 4 one ends are connected with the collector electrode of triode Q2, the other end is connected with the inverting input of operational amplifier T1, and described diode D1 mono-end is connected with the collector electrode of triode Q2, the other end is connected with the output of operational amplifier T1.
Again further, the base stage of described triode Q1 is connected with pull-up resistor R1, and the base stage of described triode Q2 is connected with pull-up resistor R2.
In order to improve the overall performance of circuit, described signal amplification circuit also comprises base stage and the resistance R between ground 9 that is connected in triode Q3, be connected in emitter and the resistance R between ground 10 of triode Q3, be connected in in-phase input end and the resistance R between ground 11 of operational amplifier T3, be connected in inverting input and the resistance R between ground 12 of operational amplifier T3.
Compared with prior art, the utlity model has following beneficial effect:
(1) the utility model is designed to one by audio signal sample circuit, filter circuit, detecting circuit, signal amplification circuit, and has selected the components and parts that cost is minimum, effect is best to carry out circuit design according to actual conditions, accords with the demands of the market.
(2) the utility model is simple in structure, uses less components and parts to realize anti-interference function, and with low cost, volume is small and exquisite, and cost performance is higher, is applicable to large-scale promotion application.
(3) in the utility model, adopt and both to have had circuit that high pass filter function also has the low-pass filtering function as filter circuit, circuit structure is very ingenious, and anti-interference effect is fairly obvious, realistic demand.
The accompanying drawing explanation
Fig. 1 is circuit theory diagrams of the present utility model.
Embodiment
The utility model is described in further detail below in conjunction with drawings and Examples, and execution mode of the present utility model includes but not limited to the following example.
Embodiment
Not high in order to solve the loud speaker cost performance existed in prior art, the problem that is unfavorable for some mini-plant uses cheaply, as shown in Figure 1, the utility model discloses a kind of audio amplifier circuit with filter function, comprise the audio signal sample circuit, inverting input is connected with the output of audio signal sample circuit by resistance R 4, and the operational amplifier T1 that output is connected with the output of audio signal sample circuit by diode D1, and the filter circuit be connected with the inverting input of operational amplifier T1, the signal amplification circuit that input is connected with filter circuit, the output of described operational amplifier T1 is connected by diode D2 with inverting input, described filter circuit comprises the resistance R 8 that in-phase input end passes through to be connected successively, resistance R 6, capacitor C 2, the operational amplifier T2 that resistance R 5 is connected with the inverting input of operational amplifier T1, be connected in in-phase input end and the capacitor C between ground 4 of operational amplifier T2, one end is connected between capacitor C 2 and resistance R 6, the resistance R 7 of other end ground connection, one end is connected between resistance R 6 and resistance R 8, the other end is connected in the capacitor C 3 of the output of operational amplifier T2, described signal amplification circuit comprises the triode Q3 that base stage is connected with the output of operational amplifier T2, the operational amplifier T3 that in-phase input end is connected with the emitter of triode Q3 by electrochemical capacitor C5, be connected in inverting input and the capacitor C between output 6 of operational amplifier T3, after series connection, be parallel to capacitor C 7 and the resistance R 13 at capacitor C 6 two ends.Wherein, resistance R 4, diode D1, diode D2, operational amplifier T1 have formed detecting circuit.
Specifically, described audio signal sample circuit comprises triode Q1, the triode Q2 that base stage is connected with the collector electrode of triode Q1, between the collector electrode that is connected in triode Q2 and ground and capacitor C 1 and the resistance R 3 of mutually connecting, be connected in the base stage of triode Q1 and the buzzing sheet U between ground, described resistance R 4 one ends are connected with the collector electrode of triode Q2, the other end is connected with the inverting input of operational amplifier T1, and described diode D1 mono-end is connected with the collector electrode of triode Q2, the other end is connected with the output of operational amplifier T1.
Again further, the base stage of described triode Q1 is connected with pull-up resistor R1, and the base stage of described triode Q2 is connected with pull-up resistor R2.
In order to improve the overall performance of circuit, described signal amplification circuit also comprises base stage and the resistance R between ground 9 that is connected in triode Q3, be connected in emitter and the resistance R between ground 10 of triode Q3, be connected in in-phase input end and the resistance R between ground 11 of operational amplifier T3, be connected in inverting input and the resistance R between ground 12 of operational amplifier T3.
On the basis of foregoing circuit, the present embodiment also is connected with part auxiliary element and line, and be used to guaranteeing the normal operation of circuit, the use of these auxiliary elements belongs to the circuit application custom of industry universal, does not repeat them here.
According to above-described embodiment, just can realize well the utility model.