SU653741A1 - Width-modulated signal-to-voltage converter - Google Patents

Description

The invention relates to a pulsed technique, namely, converters of a pulse-width modulated signal into a voltage, and can be used in automation, telemechanics and computer technology.

A pulse voltage to voltage converter is known that contains integrating and output memory capacitors connected to the input of a comparison element, the output of which is connected to the input of a trigger, the output of which is connected to the input of a key. To increase the dynamic accuracy, it also contains a transducer of the difference in the duration of two pulses into a current ii.

However, it has a narrow range of conversion.

The closest in technical essence to the proposed is a converter of a pulse-width modulated signal to a voltage containing an integrator, to the input of which a reference voltage source and a dynamic memory device with a storage capacitor connected to the integrator output are connected.

The control input of the dynamic storage device and the installation input of the initial state of the integrator are connected to the input side of the converter via a driver and short pulse 2.

However, this converter does not convert signals with a duty cycle equal to zero or one, i.e. has insufficient input range.

The purpose of the invention is to expand the range of the input signal.

This is achieved by the fact that the converter contains a modulated signal into a voltage containing an integrator, to the input of which is connected the first source of the reference voltage, a dynamic storage device with a storage capacitor, connected to the output of the integrator, in which the control input of the dynamic memory the device and the setup input of the initial state of the integrator are connected to the input of the transducer body via short-pulse formers, a threshold element is additionally introduced, the input of which It is connected to the integrator output, the logic elements AND and BAN, the first input of each of which is connected to the input of the converter, and the second - with the output of the threshold element, the second source of the reference voltage, the first switch connected in parallel to the memory capacitor, the control input of which is connected to the output of the logical element BANKS, and the second switch connecting the second source of the reference voltage with a storage capacitor, the control input of which is connected to the output of the logic element I.

The drawing shows a structural electrical converter circuit.

An input signal source (not shown) is connected to the inputs of shapers of 1, 2 short pulses. The output of the imaging unit 1 is connected to the control input of the analog switch 3 of the integrator 4, which contains the integrated capacitor 5 and the analog switch 6. The integrator 4 is connected to the reference voltage source EI, and the output to the dynamic memory device 7, which contains the storage capacitor 8 and the analog switch 9 The output of the integrator 4 is also connected to the input of the threshold element 10, and the output of the latter is connected to the information inputs of the logic elements 11 and BAN 12, the control inputs of which are connected to the input signal source. but. The outputs of the logic elements 11 and BAN 12 are connected to the control inputs of two analog switches 13 and 14, respectively, one of which is connected in parallel to the storage capacitor 8 and the other between this capacitor and the source of the reference voltage E, ..

The converter works in the following way.

Unipolar constant-frequency pulses are received at the input of the converter. The width of them is modulated on the trailing edge. The short pulse generated by the shaper 1 and coinciding in time with the leading edge of the input pulse arrives at the key 3, the latter closes and discharges the integrating capacitor 5 to zero. After the cessation of the short pulse, the key 3 is blurred. The voltage at the output of the integrating device 4 begins to increase linearly by integrating the constant voltage of the reference source EI. A short pulse generated by shaper 2 and coinciding in time with the falling edge of the input pulse is sent to keys 6 and 9. During this pulse, key 9 closes and capacitor-8 remembers the output voltage of the integrating device 4. The output voltage of the integrating device 4 is not changed, since the key 6 is open

a short impulse for the duration of the action of the latter. Voltage on the storage capacitor 8 and, accordingly, at the output of the converter varies in proportion to the width of the input pulses. The voltage at the output of the integrating device 4 in the presence of a pulse sequence at the input of the converter has a saw-tooth shape. The amplitude of this voltage does not exceed the trigger level of the .10 threshold element, the output of which is absent. The keys 13, 14 are open, since there are no signals from the outputs of logic gates And and 12. When the filling factor of the width-modulated signal at the converter input is zero or one, there are no short pulses coming to the key 3 of the integrating device 4. the voltage integration account of the reference source EI exceeds the trigger level of the threshold element 10. The latter is triggered, and the signal from its output through one of the logic elements 11 or 12 is fed to one of the keys 13, 14. The state (open, closed) of the logic elements 11 and 12 controls the input signal. If the fill factor of the micro-modulated signal is zero, the signal from the output of the threshold element 10 through the open logic element 12 enters the key 14 and closes it. The storage capacitor 8 is discharged to zero and the output voltage of the converter will be zero. If the filling factor of the spurious-medullable signal is equal to one, the signal from the output of the threshold element 10 through the open logic element 11 enters the DZ key and closes it. In this case, parallel to the memory capacitor 8, a source of the reference voltage E. is connected. The voltage of the reference source is equal to the amplitude value of the sawtooth voltage at the output of the integrating device 4 tfi in the presence of a pulse sequence at the input of the converter, the transmitter. In this case, the output voltage of the converter is maximum.

Thus, the input signal range of the converter is filled to the values equal to zero and one by the fill factor.

Claims (2)

1. Author's certificate N ° 457177 cl. H 03 K 9/08, 1972. 2. Certificate of author number 203736, cl. H 03 K 9/08, 1966.