JPS6025928B2 - polyphase oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiphase oscillator in which the phase shift relationship of each phase triangular wave with respect to the basic triangular wave remains constant even when the frequency changes.

Conventionally, many polyphase oscillators are used in which the phase difference between each phase is set using a CR time constant.

That is, as shown in Fig. 1a, first, a fundamental wave is extracted from a triangular wave oscillator 1, and then the phase is sequentially shifted by phase shifters 2 and 3 using a CR time constant, and a wave shifted by 120 degrees with respect to the fundamental wave is obtained. , 240o phase shifted waves are output. One example of the phase shifters 2 and 3 is as shown in Figure b, in which c and r are connected to the (10) input terminal of the operational amplifier 4, and a feedback resistor r3 is connected to the (1) input terminal, respectively. things are used. However, this configuration has the disadvantage that when the frequency changes, the phase difference between each phase cannot be made constant unless the constants of C and R are adjusted each time. An object of the present invention is to provide a multiphase oscillator in which the phase shift relationship of each phase with respect to the fundamental wave is constant even when the frequency changes.

In order to achieve the above object, the multiphase oscillator of the present invention includes a first triangular wave generator that generates a reference triangular wave, and a second triangular wave generator that generates a triangular wave of the same period and shifts the phase by a certain amount.
In a polyphase oscillator consisting of the following triangular wave generator, the first
a circuit that detects a time point corresponding to the turning point on both sides of the phase-shifted waveform of the second or lower triangular wave generator from the output voltage of the triangular wave generator and generates a trigger signal; The present invention is characterized in that it includes means for synchronizing the turning points on both sides of the generated triangular wave.

The present invention will be described in detail below with reference to examples.

FIGS. 2a to 2c are diagrams explaining the principle of the present invention.

In other words, in the case of a three-phase triangular wave, the maximum amplitude of the waveform is Vp
If p is assumed, when the triangular wave in figure a is 1/3 Vpp on the downward slope, the triangular wave in figure b is the turning point from upward to downward, and when the triangular wave in figure a is upward and 2/3 Vpp, the triangular wave in figure b is the turning point. The triangular wave is the turning point from downhill to uphill. Also, when the triangular wave in figure a is 2'3Vpp in the downward direction,
The triangular wave in is the turning point from downhill to uphill;
When the triangular wave is 1/3 Vpp on the upstream side, the triangular wave in c in the same figure is the turning point from the upstream side to the downstream side. Therefore,
In the present invention, a trigger pulse is generated when the output voltage is 1/3 Vpp or 2/3 Vpp based on the triangular wave shown in figure a, and thereby the turning points on both sides of the triangular wave shown in figures b and c are determined. It is something.

The present invention is not limited to three-phase oscillators, but also applies to multi-phase oscillators. FIG. 3 is an explanatory diagram showing the configuration of an embodiment of the present invention according to the above-described principle, and FIGS. 4-4 are operational waveform diagrams thereof. The following will be explained in accordance with FIG. 3 while referring to FIGS. In Figure 3, the basic triangular wave generator 1
1 is an integrator 11 by connecting a tortoise pressure switching gate 11-1, an integrator 11-2, and a window comparator 11-3 in a loop.
The triangular wave shown in FIG. Accordingly, the trigger pulses shown in Fig. 4 (■) and (2) are generated. This corresponds to the turning points on both sides of the second and third phases when the triangular wave of the triangular wave generator 11 is taken as a reference. The upper and lower turning points of the second and third phases can be distinguished by the output voltage and the slope at the detection point. At the turn-around point, trigger pulses of each corresponding combination are generated as shown in FIG. 4 and sent to the corresponding triangular wave generator 12 or 13. The triangular wave generators 12 and 13 have voltage switching gates 12-1 and 13-1 and integrators 12-2 and 13, respectively.
In addition, flip-flops 12-4 and 13-4 are provided in place of the window comparators as shown in FIG.
, ■, and when a positive pulse is received, the output is positive, and when a negative pulse is received, the output is negative. This output controls on/off of the tortoise pressure switching gates 12-1 and 13-1. In this way, the outputs of the integrators 12-2 and 13-2 are taken out as triangular wave outputs 2 and 3 matching the trigger pulses 2 and 3 as shown in FIG. 4, 2 and 3, respectively. FIG. 5 shows a specific circuit example of the embodiment shown in FIG.

In the figure, the drive control voltage of an operational amplifier (OP) 20 is supplied to triangular wave generators 11, 12, and 13 connected in parallel. As mentioned above, the basic triangular wave generator 1 1 is
The fin pressure switching gate 11-1, the integrator 11-2, and the window comparator 11-3 are connected in a loop, and a triangular wave is extracted from the output of the integrator 11-2. That is, the integrator 11
12 inputs the output of OP20 to the (-) input terminal of an operational amplifier (OP) 22 which is capacitively fed back via an input resistor.
The operational amplifier (O
P) Add to the (1) input terminal of 23. A bias voltage divided by the resistors R, , R2 from the power supply +V is applied to the (10) input terminal, and feedback is further performed from the output side via the resistor 3. The output of this OP23 is given to the base of the switching transistor 21 constituting the exposure voltage cutting gate 11-1, and its collector emitter circuit is connected to the OP2.
It is connected to the (1) input terminal side of No. 2, and is controlled to be on/off with respect to ground. The details of the generation of triangular waves in this configuration are described in another proposal by the present applicant and will therefore be omitted.
Next, the output of OP22 of the integrator 11-2 is input to each (1) input terminal of the comparators 24 and 25, and the divided voltage setting voltages of 2/3 Vpp and 1/3 Vpp are applied to the (10) input terminals, respectively. Ru.

The triangular wave generated from the triangular wave generator 11 is 2'3V.
pp, 1/3 Vpp, which reverses the power of the world. The outputs of these comparators 24 and 25 are passed through operational amplifiers (OP) 26 and 27 equipped with differentiating circuits to generate trigger pulses. In this case, the waveforms at (10) input terminal ◎ point and point ■ are shown in Figure 4 ■ and ■. This output is passed through a rectifier circuit 28 and branched into two branches, one of which is a flip-flop in the triangular wave generator 12 (
FF) 12-4, and the other is input to the flip-flop (FF) 13 in the triangular wave generator 13 via the inverting amplifier 29.
Enter in 14. These flip-flops 12-4,
The waveforms ■ and ■ in FIG. 4 are obtained as the waveforms at points ■ and ■ of the (10) input terminal of 13-4. This is the output 2, 3 as mentioned above.
corresponds to the turning points on both sides of . The outputs of the flip-flops 12-1 and 13-4 are used to turn on and off the gates 12-1 and 13-1. As explained above, according to the present invention, the circuit detects the time point corresponding to the turning point on both sides of the polyphase waveform of the second and subsequent triangular wave generators from the output voltage of the first triangular wave generator, and generates a trigger signal. and a means for synchronizing the turning points on both sides of the triangular waves generated by the second and subsequent triangular wave generators with the nuclear trigger signal.

This applies not only to the three-phase shown in the example but also to multi-phase.
Even if the frequency changes, the phase shift relationship of each phase can be kept constant with respect to the base triangular wave.

[Brief explanation of the drawing]

Figures 1a and b are explanatory diagrams of a conventional example, Figures 2 a to c are diagrams that explain the principle of the present invention, Figure 3 is an explanatory diagram showing the configuration of an embodiment of the present invention, and Figures 4 - FIG. 3 is an explanatory diagram of the operation of the embodiment, and FIG. 5 is a specific circuit example of the embodiment of FIG.
, 12 and 13 are triangular wave generators, 15 is a voltage comparator, 16 is a trigger waveform forming circuit, 11-1 is a haze pressure switching gate, 11-2 is an integrator, and 11-3 are window comparators. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. In a polyphase oscillator consisting of a first triangular wave generator that generates a reference triangular wave, and second and subsequent triangular wave generators that generate triangular waves of the same period as the first triangular wave generator and each performs a fixed amount of phase shift, the first triangular wave generator A circuit that generates a trigger signal by detecting the time point corresponding to the turning point on both sides of the phase-shifted waveform of the second or lower triangular wave generator from the output voltage of the triangular wave generator, and a circuit that generates a trigger signal in the second or lower triangular wave generator. A multiphase oscillator characterized by comprising means for synchronizing turning points on both sides of a triangular wave.