SU767968A1 - Voltage-to-code converter - Google Patents

Description

(54) CONVERT / VOLTAGE BODY TO CODE

one

The invention relates to the field of computing and can be used in automatic control systems and information processing.

The invention can be used in voltage converters from precision analog sensors to binary code, as well as for transmitting analog signals over communication channels with high accuracy.

A voltage converter is known in the code containing an integrator, the first input of which is connected to the input bus, and the output — via two comparison devices — is connected to the corresponding input; the inputs of the feedback driver, one output of which is connected to the second and third inputs of the integrator, and the second the outputs are connected with the first inputs of the two Elements And, the second inputs of which are connected to the bus of clock pulses, and the outputs - to the inputs of the reversible counter 1.

The disadvantage of the device is that it requires a large capacitor in the integrator, especially in cases where high accuracy of the conversion of input signals close to zero is required. As a result, complete microminiaturization of the converter becomes impossible, which in some cases leads to a significant increase in the size and mass of the device and, consequently, to a decrease in its reliability.

The aim of the invention is to increase the reliability of the device.

The goal is achieved by the fact that in a voltage converter into a code containing an integrator, the first input of which 10 is connected to the input bus and the output is connected via two comparison devices to the corresponding inputs of the feedback pulse generator, the first outputs of which are connected to the second and third inputs of the integrator, and the second outputs are connected to the first inputs of two And elements, and the second inputs of which are connected to the bus of clock pulses, and the outputs - to the inputs of the reversible counter, the OR element, a counter, three Ger, two reference voltage source with the keys on

20 output connected to the fourth and fifth inputs of the integrator, and the outputs of the elements AND through the element OR connected to the input of the zero setting of the counter, the counting input

which is connected to the additional clock pulse bus, and the output to the counting input of the trigger, the outputs of which are connected to the control inputs of the keys.

The invention is illustrated by the functional diagram of the converter shown in FIG. one; la fig. 2 shows the output characteristics of the voltage converter. frequency

The circuit contains integrator 1, comparing devices 2, 3, impulse feedback driver 4, elements AND 5, 6, reversible counter 7, element OR 8, counter 9, trigger 10, keys II, 12.

The device consists of the following devices.

Integrator I, which integrates the input voltage U. and reference voltages + i.s. -UjT-; + it is UjT, and is connected by an output to one of the inputs of the comparison devices 2, 3. The latter compares the output voltage of the integrator with the reference voltages connected to the second inputs of the comparison devices 2, 3.

The signals from the outputs of blocks 2, 3 connected to the inputs of the feedback pulse shaper are used to generate pulses, the duration of which is determined by the period of the clock pulses, and the amplitude by the reference voltages + is and the pulses go to the first inputs of the And 5, 6 elements and to the input integrator.

Elements And 5, 6 separate the pulses from the sequence of clock pulses TI, according to the signals from the driver outputs. Im pulse with the outputs of these circuits are fed to the inputs of the reversible counter 7, where the output code is formed.

The device works as follows.

In the initial state, all keys except one 11 or 12 are open, the output voltage of the integrator is zero. When input voltage is applied, the integrator output voltage rises to m0. time when the signal from the corresponding comparison device starts forming a pulse at the output of the driver 4 and the voltage at the integrator output will decrease. A positive input voltage corresponds to a signal from the output of the comparator 3 device and a negative pulse at the output of the shaper 4. A negative signal is from the output of the comparator 2 device and a positive impulse on the shaper 4. The outputs of elements 5 and 6 are the outputs of the voltage-frequency converter. The impulses from the output are summed further by the forwarding counter 7, where the output code is formed. Pointer impulses; also arrive at the element OR 8 and then act on the input of the zero setting of the counter 9.

TIg clock pulses from the output, n counter 9, which appears only if before the pulses at the input of the zero setting have more time to fill the counter with pulses 9, are continuously fed to the counter input of the counter, controls trigger 10 on the counting input . The trigger outputs control the operation of the keys 11, 12, ensuring their antiphase opening and closing. Thus, at small input voltages, when the frequency of the pulses from the output of the voltage-to-frequency converter reaches a certain minimum value, the reference voltages switch and the frequency jumps. increases. As a result, the characteristic of the voltage-frequency converter will be discontinuous. In FIG. 2 - characteristics are shown

for cases: a) only the key is used

11, b) only key 12; c) both keys 11

and 12.

0 The designations fi and f g correspond to the frequency of the pulses at the inputs of the element OR 8. As you can see, the frequencies cannot be less than the specified minimum values fitnln and f g mltv-This important property of the converter allows reducing the integrator time constant by ten times. Is full. microminiating becomes possible.

Claims (1)

1. US patent No. 3480766, CL.340-347, published. 1969 (prototype).