CN101977041A - Sawtooth wave generating circuit with self-adjusting amplitude, period and duty ratio - Google Patents

Abstract

The invention relates to a sawtooth wave generating circuit with self-adjusting amplitude, period and duty ratio, belonging to the field of instruments and meters. The sawtooth wave generating circuit comprises a singlechip, a digital potentiometer, a sawtooth wave generating circuit as well as a keyboard circuit and a display circuit connected with the singlechip. The sawtooth wave generating circuit is characterized in that resistors R3, R4, R5 and R6 are adjustable resistors in the digital potentiometer; the singlechip can control resistance values of the resistors R3, R4, R5 and R6; and the keyboard circuit and the display circuit set and display the amplitude, the period and the duty ratio. In the invention, common manual adjusting potentiometers are substituted by a plurality of adjustable resistors in the digital potentiometer, therefore, the resistance value of the digital potentiometer is controlled by the singlechip, and realtime change of the amplitude, the period and the duty ratio of a sawtooth wave is realized.

Description

The self-adjustable saw-tooth wave generating circuit of a kind of amplitude, cycle and duty ratio

Technical field

The present invention is the self-adjustable saw-tooth wave generating circuit of a kind of amplitude, cycle and duty ratio, belongs to instrument field, can be used in various instrument and meters and the control unit.

Background technology

Saw-tooth wave generating circuit in present instrument and meter or some control units, the method for manual adjustments potentiometer is all adopted in the adjusting of its amplitude, cycle, duty ratio, and real-time is relatively poor, and this is the problem that present saw-tooth wave generating circuit exists; Electric type student Experiment of Electronic Technology exercise equipment and single chip computer experiment exercise equipment are separate in the university, the experiment training resource does not organically combine, the experimental resources utilance is low, be a kind of wasting of resources, the knowledge of student's study effectively, continuously, does not synthetically obtain consolidating and using yet.

Summary of the invention

The objective of the invention is to solve amplitude, cycle, the duty ratio of real-time regulated sawtooth waveforms, a kind of adjusting that realizes amplitude, cycle and the duty ratio of sawtooth waveforms by the computer control digital regulation resistance is provided.

To achieve these goals, the present invention has taked following technical scheme:

The self-adjustable saw-tooth wave generating circuit of a kind of amplitude, cycle and duty ratio comprises single-chip microcomputer, digital regulation resistance, saw-tooth wave generating circuit and keyboard circuit that is connected with single-chip microcomputer and display circuit.The resistance value of adjustable resistor R3, R4, R5, R6 in the output regulating and controlling digital regulation resistance of single-chip microcomputer, the sawtooth waveforms output of the output control saw-toothed wave generator of digital regulation resistance.Keyboard circuit and display circuit are as the setting and the demonstration of amplitude, cycle, duty ratio.

In above-mentioned a kind of amplitude, cycle and the self-adjustable saw-tooth wave generating circuit of duty ratio, it is 89C52 that described single-chip microcomputer adopts the chip model, it is X9241U that described digital regulation resistance adopts the chip model, described saw-tooth wave generating circuit is made of operational amplifier, it is LM324 that operational amplifier adopts the chip model, specifically being connected between each device:

1 of 89C52,2 pin connect 14 of X9241U respectively, 9 pin, the ground of the 20 pin connection+5V power supplys of 89C52, the 40 pin connection+5V power supplys of 89C52,4 of X9241U, 5,15,16,10 pin link together and are connected with the ground of+5V power supply, 20 pin of X9241U are connected with+5V power supply, 3 of X9241U, 1,8,6 pin link together and are connected with 3 pin of LM324,7 pin of X9241U are connected with 7 pin of LM324,12 of X9241U, 18 pin link together and are connected with an end of capacitor C, the other end of capacitor C is connected 11 of X9241U with 7 pin of LM324,13 pin link together and with diode D ₁Negative electrode connect, 17,19 pin of X9241U link together and with diode D ₂Anode connect diode D ₁Anode and diode D ₂Negative electrode link together and be connected with 2 pin of X9241U, 2 pin of X9241U connect the end of bi-directional voltage stabilizing pipe VZ, the ground of the other end of VZ+5V power supply, 2 pin of X9241U connect resistance R ₇An end, resistance R ₇The other end connect 1 pin of LM324,2 pin of LM324 connect resistance R ₁An end, resistance R ₁The ground of other end connection+5V power supply, 5 pin of LM324 connect resistance R ₂An end, resistance R ₂The ground of other end connection+5V power supply, the 4 pin connection+12V power supplys of LM324, the 11 pin connection-12V power supplys of LM324 ,+5V power supply with ± the 12V power supply altogether.

The invention has the advantages that the common manual regulator potentiometer that is used to change amplitude, cycle and the duty ratio of saw-tooth wave generating circuit with a plurality of adjustable resistors replacements in the digital regulation resistance, thereby, realize amplitude, cycle and the duty ratio of real time altering saw-tooth wave generating circuit by resistance value with the Single-chip Controlling digital regulation resistance.

Description of drawings:

The self-adjustable saw-tooth wave generating circuit block diagram of a kind of amplitude of Fig. 1, cycle and duty ratio

The self-adjustable saw-tooth wave generating circuit figure of a kind of amplitude of Fig. 2, cycle and duty ratio

The self-adjustable saw-tooth wave generating circuit oscillogram of a kind of amplitude of Fig. 3, cycle and duty ratio

Embodiment:

The present invention is described in detail below in conjunction with accompanying drawing 1, Fig. 2, Fig. 3.

The self-adjustable saw-tooth wave generating circuit block diagram of a kind of amplitude, cycle and duty ratio as shown in Figure 1, the self-adjustable saw-tooth wave generating circuit figure of a kind of amplitude, cycle and duty ratio as shown in Figure 2, the self-adjustable saw-tooth wave generating circuit oscillogram of a kind of amplitude, cycle and duty ratio is as shown in Figure 3.In Fig. 1, single-chip microcomputer links together by the mode and the digital regulation resistance of serial communication, a plurality of adjustable resistors of digital regulation resistance are connected with saw-tooth wave generating circuit, saw-tooth wave generating circuit is according to the determined amplitude of adjustable resistor value, cycle and duty ratio output respective saw teeth wave voltage, keyboard circuit connects single-chip microcomputer and can be used for keying in respective saw teeth wave amplitude, cycle and duty ratio or out of Memory, and display circuit connects sawtooth waveforms amplitude, cycle and duty ratio or the out of Memory that single-chip microcomputer is used for display setting.

Fig. 2 is concrete connecting circuit figure.In Fig. 2,89C52 is a single-chip microcomputer; X9241U is a digital regulation resistance, include 4 adjustable resistors, 1,2,3 pin wherein, 6,7,8 pin, 11,12,13 pin, 17,18,19 pin are respectively three pins of 4 adjustable resistors in the digital regulation resistance, with these 4 adjustable resistors difference called after resistance R ₃, R ₄, R ₅, R ₆, wherein 1 pin, 6 pin, 13 pin, 19 pin are the scalable end of 4 resistance; LM324 is the integrated circuit (IC) chip that includes 4 operational amplifiers, and 3 pin and 5 pin are the in-phase input end of two operational amplifiers wherein, and 2 pin and 6 pin are the inverting input of these two operational amplifiers, and 1 pin and 7 pin are the output of these two operational amplifiers; Physical circuit connects as follows:

1 of 89C52,2 pin connect 14 of X9241U respectively, 9 pin, the ground of the 20 pin connection+5V power supplys of 89C52, the 40 pin connection+5V power supplys of 89C52,4 of X9241U, 5,15,16,10 pin link together and are connected with the ground of+5V power supply, 20 pin of X9241U are connected with+5V power supply, 3 of X9241U, 1,8,6 pin link together and are connected with 3 pin of LM324,7 pin of X9241U are connected with 7 pin of LM324,12 of X9241U, 18 pin link together and are connected with an end of capacitor C, the other end of capacitor C is connected 11 of X9241U with 7 pin of LM324,13 pin link together and with diode D ₁Negative electrode connect, 17,19 pin of X9241U link together and with diode D ₂Anode connect diode D ₁Anode and diode D ₂Negative electrode link together and be connected with 2 pin of X9241U, 2 pin of X9241U connect the end of bi-directional voltage stabilizing pipe VZ, the ground of the other end of VZ+5V power supply, 2 pin of X9241U connect resistance R ₇An end, resistance R ₇The other end connect 1 pin of LM324,2 pin of LM324 connect resistance R ₁An end, resistance R ₁The ground of other end connection+5V power supply, 5 pin of LM324 connect resistance R ₂An end, resistance R ₂The ground of other end connection+5V power supply, the 4 pin connection+12V power supplys of LM324, the 11 pin connection-12V power supplys of LM324 ,+5V power supply with ± the 12V power supply altogether.Keyboard circuit and display circuit and single-chip microcomputer be connected to general custom circuit connection, do not provide physical circuit.

Fig. 3 is the output voltage wave of several Key Points in Fig. 2 circuit, in the concrete below working method explanation of description is arranged.

Concrete working method is as follows:

As shown in Figure 2,1,89C52 passes through, and 2 pin are connected with 14,9 pin of X9241U, set up serial communication each other, single-chip microcomputer is with this resistance value that changes the inner a plurality of potentiometers of digital regulation resistance, and concrete communication mode each other can be consulted the operation instruction of X9241U; u _O1What export is square wave, and its amplitude is decided by bi-directional voltage stabilizing pipe VZ, as shown in Figure 3; u _O2What export is sawtooth waveforms, but the equal real-time regulated of its amplitude, cycle and duty ratio, u _O2Cycle be T, T=T ₁+ T ₂, duty ratio is defined as D=T ₁/ T, as shown in Figure 3.

Concrete working method is: 89C52 is according to numerical value or sawtooth waveforms amplitude, cycle and the change in duty cycle rule of sawtooth waveforms amplitude, cycle and the duty ratio keyed in by keyboard, carry out serial communication by calculating the back with X9241U, regulate 4 adjustable resistors of its inside, the amplitude of real time altering sawtooth waveforms, cycle and duty ratio; The amplitude of sawtooth waveforms is by regulating resistance R ₃, R ₄Decide, concrete computing formula is:

$U_{\mathrm{om}}=\frac{R_4}{R_3}{U}_Z...\left(1\right)$

By D ₁, R ₅, C, R ₃, R ₄Constitute the discharge path of saw-tooth wave generating circuit, be T its discharge time ₁,

Concrete computing formula is:

$T_1=2R_{5}C\frac{R_4}{R_3}...\left(2\right)$

By D ₂, R ₆, C, R ₃, R ₄Constitute the charging path of saw-tooth wave generating circuit, its charging interval is T ₂, concrete computing formula is:

$T_2=2R_{6}C\frac{R_4}{R_3}...\left(3\right)$

The computing formula of the duty ratio D of sawtooth waveforms is:

$D=\frac{T_1}{T}=\frac{R_5}{R_5+R_6}...\left(4\right)$

If only change integrating capacitor C, can change the period T of sawtooth waveforms, but duty ratio D does not change.

Claims (2)

1. the self-adjustable saw-tooth wave generating circuit of amplitude, cycle and duty ratio comprises single-chip microcomputer, digital regulation resistance, saw-tooth wave generating circuit and keyboard circuit that is connected with single-chip microcomputer and display circuit; It is characterized in that: adjustable resistor R in the output regulating and controlling digital regulation resistance of single-chip microcomputer ₃, R ₄, R ₅, R ₆Resistance value, the sawtooth waveforms output of the output of digital regulation resistance control saw-toothed wave generator; Keyboard circuit and display circuit are as the setting and the demonstration of amplitude, cycle, duty ratio.

2. a kind of amplitude according to claim 1, cycle and the self-adjustable saw-tooth wave generating circuit of duty ratio, it is characterized in that: it is 89C52 that described single-chip microcomputer adopts the chip model, it is X9241U that described digital regulation resistance adopts the chip model, described saw-tooth wave generating circuit is by operational amplifier, it is LM324 that operational amplifier adopts the chip model, specifically being connected between each device:

1 of 89C52,2 pin connect 14 of X9241U respectively, 9 pin, the ground of the 20 pin connection+5V power supplys of 89C52, the 40 pin connection+5V power supplys of 89C52,4 of X9241U, 5,15,16,10 pin link together and are connected with the ground of+5V power supply, 20 pin of X9241U are connected with+5V power supply, 3 of X9241U, 1,8,6 pin link together and are connected with 3 pin of LM324,7 pin of X9241U are connected with 7 pin of LM324,12 of X9241U, 18 pin link together and are connected with an end of capacitor C, the other end of capacitor C is connected 11 of X9241U with 7 pin of LM324,13 pin link together and with diode D ₁Negative electrode connect, 17,19 pin of X9241U link together and with diode D ₂Anode connect diode D ₁Anode and diode D ₂Negative electrode link together and be connected with 2 pin of X9241U, 2 pin of X9241U connect the end of bi-directional voltage stabilizing pipe VZ, the ground of the other end of VZ+5V power supply, 2 pin of X9241U connect resistance R ₇An end, resistance R ₇The other end connect 1 pin of LM324,2 pin of LM324 connect resistance R ₁An end, resistance R ₁The ground of other end connection+5V power supply, 5 pin of LM324 connect resistance R ₂An end, resistance R ₂The ground of other end connection+5V power supply, the 4 pin connection+12V power supplys of LM324, the 11 pin connection-12V power supplys of LM324 ,+5V power supply with ± the 12V power supply altogether.

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