JPS6025927B2 - 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 shift difference between each phase is set using a CR time constant.

That is, as shown in Fig. 1a, first, the fundamental wave is extracted from the triangular wave oscillator 1, and then the phase is sequentially shifted by phase shifters 2 and 3 using a CR time constant, and the phase is shifted by 12 pips with respect to the fundamental wave. A wave with a phase shift of 2400 is 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, r2 is connected to the (1) input terminal, and a feedback resistor r3 is connected, 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 second and subsequent triangular wave generators that generate triangular waves of the same period and each shift a certain amount of phase. In a polyphase oscillator consisting of a triangular wave generator, a circuit detects a time point corresponding to a one-sided turning point of a phase-shifted waveform of a second or lower triangular wave generator from the output voltage of the first triangular wave generator and generates a trigger signal; The present invention is characterized in that it includes means for synchronizing one-sided folding points of the triangular waves generated by the second and subsequent triangular wave generators with the trigger signal.

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
When the triangular wave in figure a becomes 1/3 Vpp on the downward slope, the triangular wave in figure b reaches the turning point from rising to downward, and then when the triangular wave in figure a becomes 1/3 Vpp on the upward slope. The triangular wave in c in the same figure is the turning point from uphill to downhill. The present invention focuses on this point, and first uses the triangular wave generated from one of the triangular wave generators controlled in the same phase as a reference, and the triangular wave shown in a of the same figure serving as this reference has its maximum voltage Vpp.
Detects the point in time when the phase becomes 1'3, and then synchronizes it so that it becomes the turning point on one side of the figure b or c, for example, the turning point from up to down, and the phase becomes 1200.
The purpose is to obtain three triangular waves that are shifted by each other.

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 FIG. 3, voltage-controlled triangular wave generators 11 and 12
, 13 are driven by control voltages in the same phase, and the triangular wave shown in Fig. 4 (■) generated from the triangular wave generator 11 is taken out as a reference wave, and is input to the voltage comparator 15, so that the output voltage of the triangular wave becomes 1/3 Vpp on the downward slope. The fourth point is the time when
It is detected as shown in FIG. 4 and inputted to the trigger waveform forming circuit 16 to generate the trigger pulse shown in FIG. Then, the triangular wave generator 12 receives the trigger pulse, and is set so that the triangular wave generated thereby reaches a turning point from upstream to downstream at the time of the trigger pulse, as shown in FIG. 4 (2). Similarly, when the triangular wave generated from the triangular wave generator 11 reaches 1'3Vpp on the upstream, the trigger waveform forming circuit 1
6 receives the inverted signal (■) in FIG. 4 from the voltage comparator 15 and generates the trigger pulse shown in (■) in the same figure;
As shown in FIG. 4, the triangular wave generator 13 is set so that the generated triangular wave is at the turning point from uphill to downhill at that point. In this way, the triangular wave generator 12,1
Outputs 2 and 3 are taken out from 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 in parallel to triangular wave generators 11, 12, and 13. The triangular wave generator 1 1 shown as a representative is a mirror pressure switching gate 1 1
-1, integrator 1 1-2, and window comparators 11-3 are connected in a loop, and a triangular wave is extracted from the output of integrator 11-2. That is, the integrator 11-2 is O
The output of P20 is input via an input resistor to the (1) input of an operational amplifier (OP) 22 which is subjected to capacitive feedback. The output 1 is taken out to the outside, and the window comparator 1
It is applied to the (1) input terminal of the operational amplifier (OP) 23 constituting 1-3. A bias divided by resistors R, , R2 from the power supply +Vq is applied to the (10) input terminal, and feedback is further performed from the output side via resistor R3. The output of this OP23 is given to the base of the switching transistor 21 constituting the pressure switching gate 11-1, connected to the (1) input terminal of the collector emitter circuit OP22, and controlled to be on/off with respect to ground. The operation of the main parts in such a configuration is shown in Figs. 6 a to c and Fig. 7 a,
Let me explain by quoting b.

Now, when the control voltage of OP20 is applied to the triangular wave generator 11, the output voltage of OP22 of the integrator 11-2 gradually decreases (FIG. 6a). Therefore, the voltage at the (1) input terminal of OP23 of the window comparator 11-3 gradually decreases, and (10)
When the voltage drops below the input terminal voltage, "this OP23 immediately outputs a voltage of 10 Vcc. Then, the resistors R, , R2 .
The connection of R3 is equivalent to that in FIG. 7a, and if R,=R2=R3, the voltage applied to the (10) input terminal becomes 2'3Vcc [FIG. 6b]. And window comparator 1 1
When 13 OP23 outputs 10 Vcc [Figure 6c],
The transistor 21 of the voltage switching gate 11-1 is turned on (FIG. 6d), and the (1) input terminal of OP22 is grounded. Then, the output of OP22 of the integrator 11-2 gradually increases [Fig. 6a]. Therefore, the voltage applied to the (1) input terminal of OP23 of the window converter 11-3 gradually increases, and as soon as the voltage at the (10) input terminal exceeds the 2/3 V target, OP23 increases the voltage of -Vcc. Output. Then, the connection of resistors R,, R2, and R3 becomes equivalent to that shown in Figure 7b, and the voltage applied to the (10) input terminal becomes 0 [6th
Figure b]. When the output of OP23 of the window comparator 11-3 outputs Vcc [FIG. 6c], the transistor 21 of the gate 11-1 turns off [FIG. 6d].
], the output of OP22 of integrator 1 1-2 gradually decreases [Fig. 6a]. Therefore, the input voltage to OP23 of the window comparators 11-3 gradually decreases, and when it reaches 0, the output is inverted again. Repeat this to generate a triangular wave. Next, in FIG. 5, the comparator 24
The output of OP22 of the integrator 11-2 is input to (1) the input terminal, and (10) the set voltage of 1/3 Vpp is applied to the input terminal.

The triangular wave generated from the triangular wave generator 11 is 1/3V.
When it becomes pp, the output is inverted. The output of this comparator 24 is shown in waveform 2 in FIG. This output is differentiated by a differentiating circuit 16-1 and negative pulses are cut out to obtain a waveform (2) shown in FIG. 4, which is applied to the (1) input terminal of the operational amplifier in the window comparator of the triangular wave generator 12. In addition, the output of the comparator 24 is inverted by the operational amplifier 25 to obtain the waveform (■) shown in FIG. , is also applied to the triangular wave generator 13.
Here, the comparator 24 and the operational amplifier 25 correspond to the voltage comparator 15 in FIG.
6-2 corresponds to the trigger waveform forming circuit 16. As mentioned above, when the triangular wave output from the triangular wave generator 11 is downward, the OP23 of the window comparator 11-3 (
(10) Since the voltage at the input terminal is 0, at this time (1) even if a positive trigger pulse is applied to the input terminal, the output will not be inverted.

If the triangular wave is rising, (10) the input terminal is 2'3VQ, and (1) if a trigger pulse exceeding 2'3Vcc is applied to the input state, the output of the window comparators 11-3 will be inverted and the triangular wave will be downward. Become. In the embodiment shown in FIG. 5, each triangular wave generator initially starts oscillating in phase.

Since the triangular wave generator 13 receives the first pulse when its output is up, its output immediately reverses to down. However, if the triangular wave generator 12 is connected to other triangular wave generators 11,
If the circuit was exactly the same as 13, it would always receive pulses only when the triangular wave is down, and a triangular wave in phase with the triangular wave generator 11 would be output. Therefore, as shown in the triangular wave generator 12 in FIG. 5, the output side of the integrator is connected to a diode 31.
It is connected to a window comparator via a diode 32, and further connected to a power supply voltage divided to 2/3 VQ via a diode 32. Therefore, when the triangular wave generated from the triangular wave generator 12 reaches the 2'3V ratio at the first rise, the output remains constant until the next pulse is obtained, and when the next pulse is given, the window comparator is inverted. and falls down. In this way, the turning points can be synchronized. As explained above, according to the present invention,
A trigger signal is sent to each of the second and subsequent triangular wave generators based on a predetermined output voltage of the first triangular wave generator, and one turning point of the triangular wave generated by the second and subsequent triangular wave generators is synchronized with this trigger signal. It is equipped with a means to do so.

This is applicable not only to the three-phase case shown in the example but also to multi-phase cases, and even if the frequency changes, the phase shift relationship of each phase to the basic triangular wave can always be maintained constant. be.

[Brief explanation of the drawing]

Figs. 1 a and b are explanatory diagrams of subordinate examples, Figs. 2 a to c are explanatory diagrams of the principle of the present invention, Fig. 3 is an explanatory diagram showing the configuration of an embodiment of the present invention, and Figs. 4 ■ to ■ is an explanatory diagram of the operation of the embodiment shown in FIG. 3, FIG. 5 is a specific circuit example of the embodiment of FIG. 3, and FIGS. 6 and 7 are detailed explanatory diagrams of the main parts of FIG. , 11, 12,
13 is a triangular wave generator, 15 is a voltage comparator, 16 is a trigger waveform forming circuit, 11-1 is a tortoise pressure switching gate, 11
-2 represents an integrator, and 11-3 represents a window comparator. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

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 a point corresponding to one-sided turning point 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 one side turning point of a triangular wave.