JPH02124623A - Triangle wave generator - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a triangular wave generator used as a part of a precision PMW circuit used in a motor control power source and the like.

To 11 W Turtle This type of turtle is the first. The second input voltage is selectively introduced into the integrator via a switch, the integrated output thereof is introduced into a comparator and compared with positive and negative constant voltages, and the switch is switched based on the matched output, Above 1. The second input voltage may be a constant positive and negative voltage of a reference voltage generator.

FIG. 3 is a block diagram of the above. The constant voltage generated by the reference voltage generator 21 and the inverting circuit 22
The two positive and negative voltages whose polarities are reversed through the switch 1 become the input voltages of the switch 1 and are selectively introduced into the integrator 2 via the switch 1, and the integrated output thereof is sent to the comparator 10. The comparator 10 includes an adder circuit 12 that calculates the sum of the integral output, the constant negative voltage of the reference voltage generator 21, and the integral output A, and a comparator circuit 13 that detects the coincidence of the added output and the zero potential. As shown in the figure, there is a part that generates output C when the integral output A matches a constant negative voltage, and an addition that converts the polarity of the integral output through the inverting circuit 11 and then adds it to the constant positive voltage. It has a part that generates an output B when the integral output A matches a constant positive voltage by a circuit 14 and a comparison circuit 15 that detects the match between the addition output and the zero potential, and the outputs B and C are a flip-flop. It is introduced into the set and reset terminals of the circuit 16, and its Q output is introduced into the switch 1 as a switching command.

Therefore, in this case, the output A of the integrator 2 is positive,
Every time the constant negative voltage is reached, the input of the integrator 2 is switched between the negative and positive constant voltages, and the output A of the integrator 2 changes between the positive and negative constant voltages as shown in Figure 4A. becomes a triangular wave that changes periodically.

However, when this triangular wave generator is employed in a power amplification circuit of a motor control system, the generation of vibration and noise corresponding to the frequency of the triangular wave is unavoidable.

Also, when using this in an analog multiplier circuit, if the input signal frequency is not sufficiently low compared to the triangular wave frequency, a synchronization error will occur, resulting in an unavoidable drop in accuracy. Means The present invention focuses on the fact that the stability of the oscillation frequency of a triangular wave is unrelated to the accuracy of the power of the triangular wave, and generates a triangular wave with a constant amplitude and fluctuation in frequency. It is.

That is, the present invention has the following features. A triangular wave generator that selectively introduces a second input voltage into an integrator via a switch, introduces the integrated output into a comparator, compares it with a constant positive and negative voltage, and switches the switch based on the matched output. The above No. 1. The second input voltage is characterized in that it is an added voltage of a constant positive and negative voltage of the reference voltage generator and a voltage randomly changing with respect to time of the random voltage generator.

In this case, when an additional voltage of a certain magnitude, which is a constant positive voltage plus a random voltage, is input to the integrator, the integrator integrates it and outputs an integral output that increases linearly. Ru.

When the voltage reaches a constant positive voltage, the input of the integrator is switched to a voltage obtained by adding a random voltage to the constant negative voltage. As a result, the integral output begins to decrease linearly from the above constant positive value, and when that value reaches a constant negative voltage, the input of the integrator becomes the above constant positive voltage plus the random voltage. is switched to an additional voltage of a different magnitude, and the same operation as above is repeated thereafter. Therefore, the time it takes for the integral output to reach a constant positive or negative value depends on the magnitude of the input addition voltage, and in the end, the addition voltage changes randomly around a constant value. The period of the integral output, that is, the triangular wave, also changes randomly around a constant period.

In FIG. 1 showing an embodiment of the present invention, each element surrounded by a broken line, that is, a reference voltage generator 21, an inverting circuit 22 . Switcher 1. Integrator 2. Inverting circuit 11. Addition circuit 1
2,14. The comparator circuit 13゜15.7 rip 70 tube circuit 16 is similar to that shown in FIG.
2 and the other input end of the switch 1, except that elements 31 to 37 surrounded by one-dot chain lines are interposed between the switch 2 and the other input end of the switch 1. Otherwise, the connections are the same as in FIG.

The element surrounded by the dashed dotted line supplies the added voltage of positive and negative constant voltages and random voltages to the switch 1, and generates the constant voltage and random voltage of the reference voltage generator 21. Adding circuit 3 that adds the random voltage of the voltage generator 31
2. An addition circuit 33 that similarly adds the constant negative voltage formed via the inversion circuit 32 and the random voltage;
It consists of sample and hold circuits 36 and 37 into which the added voltages of the adder circuits 32 and 33 are respectively introduced, and one-shot circuits 34 and 35 that supply sample and hold timing signals of the sample and hold circuits 36 and 37, respectively. The outputs of the comparison circuits 15 and 13 are applied to the shot circuits 34 and 35, respectively. The hold voltages of the sample and hold circuits 36 and 37 are connected to each input terminal of the switch 1.

FIG. 2 is an output waveform diagram of the portions indicated by the same symbols a to h in FIG. 1, and the operation of the above will be explained below based on this.

Now, when a certain hold voltage of the sample and hold circuit 36 is supplied to the integrator 2, the output a of the integrator 2 increases linearly, and when it matches the constant positive voltage of the reference voltage generator 21, the comparison A coincidence output signal is sent from the comparator circuit 15 of the sample-hold circuit 10, which sets the 7-lip 70-tub circuit 16, and its Q output switches the switch 1 to the output end side of the other sample-and-hold circuit 37. A held negative voltage of some magnitude is applied to the integrator 2.

As a result, the integral output a decreases at a rate of change corresponding to the input voltage. At this time, the coincidence output signal 729971 is simultaneously applied to the 729971 circuit 34, and the command signal 8 sent from there holds the input voltage h (sum of positive constant voltage and random voltage) of the sample and hold circuit 36 at that time. Ru. Subsequently, when the integral output a decreases to a constant negative voltage, a coincidence output C is sent out from the comparison circuit 13 of the comparator 10, thereby resetting the 7-rip 70-rip circuit 16, and as a result, the switch 1 is turned on. The voltage h (the sum of the constant positive voltage and the random voltage at the time of holding) held by the sample and hold circuit 36 is applied to the integrator 2.

As a result, the output a of the integrator 2 increases at a rate of change corresponding to its magnitude, which is different from the rate of change 1/2 period ago. And at the same time,
In the other sample and hold circuit 37, the input voltage f (sum of a constant negative voltage and a random voltage) at that time is held by the command signal e generated by the 729971 circuit 35 based on the coincidence output C. Thereafter, when the integral output a reaches a positive constant voltage, a coincidence output is sent out in the same way as above, and the same operation as above is repeated.

Therefore, the integral output a becomes a constant amplitude triangular wave whose period changes randomly every half period.

Furthermore, by changing the ratio of the constant voltage to the random voltage, it is possible to provide periodic fluctuations with an appropriate time width.

The effects of the invention are as described above, and the present invention makes the input voltage to the integrator which is selectively switched and introduced the sum of constant positive and negative voltages and random voltage, and generates a triangular wave with a constant amplitude and a fluctuating period. If this is used in a power amplifier for a motor, etc., the generated power will not change, but the peaks of vibration and sound will be dispersed, resulting in an ergonomically equivalent effect of reducing vibration and sound. is obtained.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a waveform diagram of the one shown in Fig. 1, and Fig. 3 is a block diagram of the prior art.
FIG. 4 is a waveform diagram of the waveform shown in FIG. 3. 32.33...addition circuit, 36.37...sample hold circuit, 1...
Switcher, 2... Integrator.

Claims (1)

[Claims] 1, the first and second input voltages are selectively introduced into the integrator via a switch, the integrated output is introduced into a comparator and compared with positive and negative constant voltages, and the matching output is used to switch the input voltage to the above-mentioned switch. The first and second input voltages are the summed voltages of a constant positive and negative voltage of a reference voltage generator and a voltage randomly changing with respect to time of a random voltage generator. Characteristic triangular wave generator