JPH0220950B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frequency/phase voltage conversion circuit that generates a voltage according to the frequency and phase of a certain signal.

Conventionally, in speed and phase control devices for servo motors and the like, a frequency-voltage converter circuit that generates a voltage according to frequency and a phase-voltage converter circuit that generates a voltage according to phase are configured as separate circuits.

Since such frequency-voltage conversion circuits and phase-voltage conversion circuits include similar circuit elements in principle, attempts have been made to share a part of both circuits in order to reduce costs (for example, in Japanese Patent Application Laid-Open No. 48-6222), it still wasn't enough.

Therefore, an object of the present invention is to provide a frequency/phase voltage conversion circuit that generates a voltage in response to both frequency change and phase change.

Hereinafter, the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention, in which reference numerals 1 and 2 are monostable multivibrators, and gates that sequentially generate sampling pulses and trigger pulses in synchronization with an input pulse signal A supplied to an input terminal 3. It constitutes a pulse generation circuit. Gate circuit 4
supplies the voltage from the power supply 5 to the charging capacitor 6 by means of a trigger pulse. Constant current source 7 discharges charging capacitor 6 with a constant current, producing a sawtooth waveform with a descending slope. This sawtooth wave is sampled by a sample-and-hold circuit 9 through a gate 8 triggered by a sampling pulse, and the sample-and-hold circuit 9 outputs the potential at that point as an output voltage to an output terminal 10. supply

The parts explained above are the same as those of the prior art, but in this embodiment, a reference signal generation circuit 11 that generates a reference pulse signal D having a reference phase is further added.
It has an AND gate 12 that takes the logical sum of input pulse signal A and reference pulse signal D, and a gate 14 that is triggered by the output of AND gate 12 and puts constant current source 13 into operation.

The waveforms of each of the above-mentioned signals I-I are shown in FIG. 2I-I.

As mentioned above, since the gate 14 is opened by the output signal E of the AND gate 12 and the discharge current increases, the slope of the downward slope to the sawtooth wave signal changes, and the potential sampled according to the change in phase difference changes. In contrast, the output of the sample-and-hold circuit 9 changes in response to changes in the frequency and phase of the input signal.

Here, if the input signal is a sine wave signal,
A waveform shaping circuit that converts a sine wave signal into a pulse signal may be inserted in series to the input terminal 3. Alternatively, instead of the AND gate 12, a phase difference detection circuit that generates a signal according to the phase difference between sine wave signals is used,
The reference signal may also be a sine wave signal, and the gate circuit 14 may be a circuit having impedance characteristics depending on the output voltage of the phase difference detection circuit.

From the above, it is clear that the frequency-phase-voltage conversion circuit according to the present invention can be used not only for speed control of servo motors but also for various control devices, has a small number of circuit elements, and can greatly contribute to cost reduction. It is.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG.
The figure is a diagram showing signal waveforms at various parts in the circuit of FIG. 1. Explanation of main symbols, 1, 2... Monostable multivibrator, 4, 8... Gate circuit, 11... Reference signal generation circuit, 7, 13... Constant current source, 9... Sample/hold circuit, 14 ...gate circuit.

Claims (1)

[Claims] 1. A gate pulse generation circuit that sequentially generates a sampling pulse and a trigger pulse in synchronization with an input pulse signal, a sawtooth wave generation circuit that generates a sawtooth wave voltage in response to the trigger pulse, and a gate pulse generation circuit that generates a sawtooth wave voltage in response to the trigger pulse; The sawtooth wave generation circuit includes a sample and hold circuit that samples and holds the voltage of the sawtooth wave, and the sawtooth wave generation circuit includes a reference pulse signal generation circuit having a reference phase, a capacitor, and a sample and hold circuit that samples and holds the voltage of the sawtooth wave. a gate circuit that charges with a predetermined voltage; a first discharge circuit that discharges the capacitor with a constant current; and a first discharge circuit that discharges the capacitor with a constant current according to a phase difference between the input pulse signal and the reference pulse signal. a second discharge circuit, and is configured to further change the slope of the slope part of the sawtooth wave voltage from the middle according to the phase difference.