CN201417602Y

CN201417602Y - Buzzer drive circuit

Info

Publication number: CN201417602Y
Application number: CN2009200741291U
Authority: CN
Inventors: 周荣; 张杰良; 谌清平; 惠滨华
Original assignee: Suzhou Luzhiyao Technology Co Ltd
Current assignee: Suzhou Luzhiyao Technology Co Ltd
Priority date: 2009-06-19
Filing date: 2009-06-19
Publication date: 2010-03-03
Anticipated expiration: 2019-06-19

Abstract

The utility model relates to a buzzer drive circuit, comprising a plurality of electrical resistors which are electrically connected, a plurality of transistors, a capacitor and a piezoelectric buzzer, wherein the capacitor is electrically connected with the piezoelectric buzzer in parallel. The instruction of the capacitor causes the piezoelectric buzzer not immediately lose voltage, further thebuzzer can send out aftersound, the volume of the aftersound becomes smaller and smaller, and the aftersound is very beautiful. The buzzer drive circuit has the advantages of simple circuit, low cost,reliable performance and beautiful aftersound, and the like, and can send out different tones.

Description

Buzzer drive circuit

Technical field

The utility model relates to a kind of buzzer drive circuit, especially a kind of piezo buzzer driving circuit.

Background technology

Hummer is as a kind of electronics news Chinese percussion instrument of integral structure, and it is widely used in making microphone device in the electronic products such as computing machine, printer, duplicating machine, alarm, electronic toy, vehicle electronics, telephone set, timer.

Existing hummer, the driving circuit that it adopts, though can send different tonequality, when stopping, its sound that sends also just stops suddenly, without any lingering sound, it is not so perfect giving people's perceived sounds.Therefore, industry is badly in need of a kind of buzzer drive circuit of new structure, improves or solves the above problems

The utility model content

Do not have the problem of lingering sound in order to overcome existing hummer, the utility model provides a kind of buzzer drive circuit, and it can fade away by enable voice when stopping, and allows the perfect naturally industry of people's perceived sounds.

The technical scheme that the prior art problem that solves the utility model is adopted is: a kind of buzzer drive circuit, it includes some resistance of electric connection, some triodes, electric capacity and piezo buzzer, wherein electric capacity electric connection in parallel with piezo buzzer.

Further, in different embodiments, in some triodes that the utility model relates to, first, second triode Q1, the Q2 that it comprises is NPN type triode, and the 3rd triode Q3 is the positive-negative-positive triode.

Further, in different embodiments, the electric capacity that the utility model relates to is the 47uf/50v electrochemical capacitor.

Further, in different embodiments, this electric capacity is connected with a resistance, and both and piezo buzzer after the series connection are connected in parallel.

Further, in different embodiments, this piezo buzzer and a resistance are connected in parallel.

Further, in different embodiments, piezo buzzer is connected with a NPN type triode, and both and this electric capacity after the series connection are connected in parallel.

Further, in different embodiments, the buzzer drive circuit that the utility model relates to also includes two input ends, is used for connecting respectively the single-chip processor i/o pin.Further, one of them input end one end is used to receive high-low level, and another input end is used to receive pwm signal.

The beneficial effects of the utility model are, it has, and circuit is simple, with low cost, dependable performance, lingering sound grace, and advantages such as different tonequality can take place.

Description of drawings

Fig. 1 is the buzzer drive circuit synoptic diagram that the utility model relates to.

Embodiment

The infinity of the passive hummer direct current resistance of piezoelectric type, it is also very big to exchange resistance, and voltage is higher during work, and electric current is very little.The passive hummer of piezoelectric type need utilize piezoelectric effect under the condition of alternating voltage, make its mechanically deform constantly stretch and shrink, make the sheet metal vibration, thereby hummer is sounded continuously, change the frequency of its alternating voltage, can make the passive hummer of piezoelectric type send different tonequality.

Further, the utility model is introduced capacitor C, and itself and the passive hummer of piezoelectric type are connected in parallel.When circuit supply stops, and the electric charge of capacitor C stored can reduce gradually.Along with the electric charge on the capacitor C reduces gradually, hummer will send lingering sound and this lingering sound volume diminishes gradually, and is very graceful.

Describe embodiment of the present utility model in detail below in conjunction with accompanying drawing.

See also shown in Figure 1, a kind of buzzer drive circuit that the utility model relates to, it includes some resistance, some triodes, electric capacity and the passive hummer of piezoelectric type.Wherein, the resistance R 1～R8 that relates in the circuit is a common metal oxide film resistance; Triode Q1, Q2 are NPN type triode (9013) commonly used, and triode Q3 is a PNP triode (9014) commonly used; BZ is the passive hummer of piezoelectric type (CBE2220BPC), and capacitor C is the 47uf/50v electrochemical capacitor.2 of A, B connect the single-chip processor i/o pin respectively.An I/O pin output of single-chip microcomputer high-low level is to the A point, and PWM (Pulse WidthModulation, the pulse-length modulation) signal of an I/O pin output of single-chip microcomputer is to the B point.

Further, resistance R 1, R3, R4, R5, R6, R8, capacitor C and triode Q1 (for example, NPN type, 9013), Q3 (for example positive-negative-positive, 9014) constitute power control circuit, provide power supply and electric current for the passive hummer BZ of piezoelectric type drives.

During use, circuit initially powers on, and the electric charge on the capacitor C is zero, and the single-chip processor i/o mouth is exported respectively to A, B 2 points.

When the A point is a high level, when the B point is low level, power supply VCC (+12V) by resistance R 5, R3 is triode Q1 (NPN, 9013) provide collector voltage and electric current, A point high level provides base voltage and electric current by resistance R 1 for triode Q1, and triode Q1 possesses turn-on condition, triode Q1 conducting, C point current potential becomes 0.3V, and D point current potential becomes 4.04V, and (VCC is through resistance R 5, the R3 dividing potential drop obtains), triode Q3 (PNP, 9014) possesses turn-on condition, triode Q3 conducting is through resistance R 6, R8, capacitor C is charged to capacitor C, E point current potential rises gradually, after the capacitor C electric charge was full of, triode Q3 ended, and E point current potential is near 12V.

When the A point is a high level, when the B point becomes high level, because E point current potential is a high level, triode Q2 conducting at once, triode Q1, also conducting of Q3 simultaneously, power supply VCC provides voltage and current by Q3, R6, R7, Q2 for hummer BZ, and hummer BZ both end voltage is about 11V.Because B point signal is PWM, the B level point becomes low level very soon.

When the A point is a high level, the B point is when high level becomes low level, and triode Q2, Q3 end, triode Q1 conducting, and the electric energy in the hummer BZ discharges by resistance R 7, and both end voltage reduces.When the A point is a high level, when the B level point uprises level again, triode Q1, Q2, Q3 conducting again, hummer BZ two ends are again high voltage (about 11V).Just there has been alternating voltage at hummer BZ two ends like this, and under the effect that this alternating voltage continues, its inner sheet metal will vibrate, and hummer BZ sounds continuously.

Last E point current potential triode Q3, R6, Q2 provide power supply and electric current for hummer BZ.When the A point is a high level, when the B point became low level, triode Q2 ended.Hummer is because the A point is a high level, and the B point is the PNM signal, the continuous conducting of triode Q2 and ending.Constantly produce alternating voltage at the BZ two ends, BZ is under the effect of alternating voltage, because piezoelectric effect constantly stretches mechanically deform.As shrinking, make the sheet metal vibration, thereby hummer BZ recurs sound.

Just can make hummer BZ send the sound of different tonequality if change the dutycycle of B point pwm signal with frequency.When the A level point becomes low level, when the B point continues as pwm signal, triode Q1, Q3 end, because the electric charge on the capacitor C can not very fast release, the current potential that F order is disappearance at once not, the also corresponding Q1 that intermittently keeps of E point current potential, current potential when Q3 ends, hummer continues pronunciation, and along with the electric charge on the capacitor C reduces gradually, the current potential that F point, E are ordered also descends gradually.Hummer will send lingering sound and this lingering sound volume diminishes gradually, and is very graceful.If there is not capacitor C, even the B point continues that PWM is arranged, when the A point was low level, because triode Q1, Q3 ended.The E point does not have current potential.Do not have voltage on the hummer, then lingering sound can not take place.

The above only is a better embodiment of the present utility model; protection domain of the present utility model does not exceed with above-mentioned embodiment; as long as the equivalence that those of ordinary skills do according to the utility model institute disclosure is modified or changed, all should include in the protection domain of putting down in writing in claims.

Claims

1, a kind of buzzer drive circuit, it includes some resistance of electric connection, some triodes and piezo buzzer, it is characterized in that: it also includes electric capacity, the electric connection in parallel with described piezo buzzer of wherein said electric capacity.

2, buzzer drive circuit according to claim 1 is characterized in that: first, second triode Q1, the Q2 that described some triodes comprise is NPN type triode, and the 3rd triode Q3 is the positive-negative-positive triode.

3, buzzer drive circuit according to claim 1 is characterized in that: described electric capacity is the 47uf/50v electrochemical capacitor.

4, buzzer drive circuit according to claim 1 is characterized in that: described electric capacity is connected with a resistance, and both and piezo buzzer after the series connection are connected in parallel.

5, buzzer drive circuit according to claim 1 is characterized in that: described piezo buzzer and a resistance are connected in parallel.

6, buzzer drive circuit according to claim 1 is characterized in that: described piezo buzzer is connected with a NPN type triode, and both and described electric capacity after the series connection are connected in parallel.

7, buzzer drive circuit according to claim 1 is characterized in that: it also includes two input ends, is used for connecting respectively the single-chip processor i/o pin.

8, buzzer drive circuit according to claim 7 is characterized in that: wherein said two input end one ends are used to receive high-low level, and another input end is used to receive pwm signal.