SU1305861A1 - Digital-to-analog converter - Google Patents

Abstract

The invention relates to automation, in particular to the control of an electric drive of CNC machines, and improves the speed by increasing the frequency of the PWM signal at the input of the low-pass filter. The digital code of the number recorded in register 1 is summed with the variable from O to counter code 2, which continuously receives pulses from the generator of 3 pulses. When the sum of the two numbers arriving at the inputs of adder 4 is greater than 2-1, adder 4 will overflow and the output of the high bit of adder 4 will go from state O to state 1 | G 1 II, in which it will remain until the counter overflows 2. The pulse duration at the transfer output of the high bit of the adder 4 is proportional to the binary number at the outputs of register 1. The pulses from the transfer output of the high bit of the adder 4 arrive at the second inputs of elements 6, 7, the second inputs of which receive the sign bit from the second register output 1. Depending on the sign of the code, the output of one of the elements 6 or 7 will be a sequence of pulses, the duration of which is proportional to the code being converted, which enters the input of the first or second key 8, 9. The key connects the sample voltage U from the output of the source 10 of the reference voltage on the inverting or non-inverting input of the operational amplifier 11, the pulse sequence is fed to the input of the low-pass filter 12, the output of which is a constant voltage proportional to the code being converted . 1 il. S SL CO O SL 00 a 11 I-I & 6ncoff 12

Description

The invention relates to automation, in particular to the control of the electric drive of CNC machines,

The purpose of the invention is to increase the speed by increasing the frequency i of the PWM signal at the input of the low-pass filter.

The drawing shows the functional diagram of the device.

The converter contains a register 1, tO pulses, and a duration equal to the length of the input whose input transforms the signed code from the input buses, counter 2, to the input of which impulses come from the generator of 3 pulses, adder 4, inverter 5, two elements 6 and 7, the first 8 and second 9 keys, the source 10 of the voltage reference U, the operational amplifier 11 and the low-pass filter 12, the output of which is the output of the device.

The device works as follows.

The device is a converter with an intermediate pulse-width conversion. The digital code of the number recorded in register 1 is bitwise summed up with the changing code from O to counter code 2, which continuously receives pulses from the generator of 3 pulses. When the sum of the two numbers entering the inputs of adder 4 is greater than 2 -1, adder 4 is full and the high bit output of adder 4 goes from state O to state 1, in which it is before counter 2 is full, i.e. when counter 2 returns to state O. The pulse duration at the high-carry transfer output of adder 4 is proportional to the binary number at the outputs of register 1

Where

NX-Tp NX-TO

register output code 1

a pulse following period at the output of the pulse generator 3; T is the pulse duration on

the output of the high-order transfer of the adder 4. Pulses from the high-transfer transfer output of the adder 4 arrive at the second inputs of elements 6 and 7, the second inputs of which receive the significant bit from the second output of register 1. Depending on the sign of the code at the output of one of elements And 6 or 7 will be a sequence of pulses.

whose duration is proportional to the code being converted, which is fed to the input of the first 8 or second 9 key. The key connects the reference voltage and from the output of the source 10 of the reference voltage to the inverting or non-inverting input of the operational amplifier 11, respectively, with a period equal to the period following

pulses in a sequence. From the output of the operational amplifier 11, the pulse sequence is fed to the input of the filter 12 low frequencies. From the pulse train, the filter selects a constant voltage proportional to the code to be transformed, the polarity of which is determined by the sign of the code.

Claims (1)

Invention Formula five 0 five 0 A digital-to-analog converter containing a pulse generator, the output of which is connected to the counter input, a source of reference voltage, the output of which is connected to the information input of the first key, a register whose inputs are the input terminals of the converter, a low-pass filter whose output is the output of the converter , I differ, with the fact that, in order to increase speed, an adder, an inverter, two AND elements, a second switch and an operational amplifier are entered into it, the first outputs of the register are connected according to The first inputs of the adder, the second inputs of which are connected to the corresponding outputs of the counter, the output to the first inputs of the first and second elements AND, the second output of the register are connected to the second input of the first element AND and the input of the inverter's house whose output is connected to the second input The second element And, the outputs of the first and second elements And are connected to the control inputs of the first and second keys, respectively; the information input of the second of which is connected to the output of the reference voltage source, the output of the first and second to The keys are connected respectively to the inverting and non-inverting inputs of the operational amplifier, the output of which is connected to the input of the low-pass filter.