SU1520661A1 - Digit-analog converter - Google Patents

Abstract

The invention relates to the field of automation and can be used to convert digital information into analog information, as well as as part of analog-to-digital converters. The purpose of the invention is to simplify the device while maintaining speed. The digital-analog converter contains a resistive matrix of type 1 R-2R, bit switches, each of which is made on the first 2 and second 3 CMOS transistors, the converter 4 is the voltage, made in the form of the first 5 and second 6 transistors, Zener diode 7 and p These resistors are 8-12, and the register is 13. A positive effect has been achieved by simplifying the implementation of a 4-voltage converter and bit switches. 1 hp f-ly, 1 ill.

Description

The invention relates to automation and can be used to convert digital information to analog, as well as as part of analog-to-digital converters.

The purpose of the invention is the simplification while maintaining performance.

The drawing shows a functional diagram of a digital-to-analog converter.

The digital-to-analog converter contains a resistive matrix 1 of type R-2R, bit switches, each of which is made in the form of the first 15 * first and second 3 CMOS transistors, the current-voltage converter 4 is made in the form of the first 5 and second 6 transistors, a zener diode 7 and five resistors 8-12, and register 13. 20

The converter operates as follows.

The converted code is entered into register 13, from the direct and inverse outputs of which the code is fed to the gates of the 25 gates of the first 2. and second 3 CMOS transistors, translating the corresponding ones into the on state. Using resistive matrix 1, binary-weighted currents are formed, which 30 through the switched-on CMOS transistors 2 and 3 are supplied respectively to the first and second information inputs of the current converter 4 - voltage, the output of which is formed by the output of the digital-to-analog converter proportional to the input code.

The mode of the transistors 5 and 6 of the converter 4 is the current - voltage is set using the zener diode 7 and the resistor 10, and the current flowing through each transistor without taking into account the currents of the resistive matrix is set by the resistors 11 and 12. In this case, the value of this current should be selected substantially greater than the maximum value of the converted current from the output of the resistive matrix 1. This requirement ensures the equipotentiality of the emitters of both transistors 5 and 6 for any value of the converted code. Resistors 8 and 9 are the load resistances of transistors 5 and 6.

A positive effect is achieved by simplifying the current-voltage converter.

Claims (2)

Claim 1. A digital-to-analog converter containing a resistive matrix of type R - 2R, made in the form of η - 1 series-connected communication resistors, η bit resistors and a matching resistor, the first conclusions of η - 1 bit resistors are connected respectively to the first conclusions η -1 of communication resistors, the first the output of the nth bit resistor is combined with the first output of the terminating resistor and with the second output (nl) -ro of the communication resistor, the first output of the first communication resistor is the input voltage reference bus, and the second conclusions are η bit resistors are connected to the information inputs of the corresponding bit switches, the first outputs of which are connected to the first information input " current-voltage converter * the output of which is an output bus, with the fact that, in order to simplify while maintaining speed, a register is introduced into it, the inputs of which are the input bus of the code to be converted, direct and inverse the outputs of the register are connected respectively to the first and second control inputs of the corresponding bit switch, the second output of the terminating resistor of the resistive matrix type R - 2R is combined with the second outputs of the bit switches and connected to the second information input dy converter current - voltage and the pre-forming _r current - voltage is in the form of two transistors, zener diode and five resistors, the base of the first transistor is integrated with the base of the second transistor, the anode of the zener diode and the first terminal of the first resistor, the second terminal of which is combined with the first terminals of the second and the third resistor and is a zero potential bus, emitters of the first and second transistors are connected to the first terminals of the fourth and fifth resistors respectively and are the first and second, respectively information inputs of the current-voltage converter, the cathode / zener diode is combined with the second terminals of the fourth and fifth resistors and connected to the input voltage reference bus, the collector of the first transistor is connected to the second terminal of the second resistor and is the output of the code-voltage converter, the second terminal of the third resistor is connected to the collector of the second transistor. 2. The converter ποπ, Ι, л л и и ч тем тем with the fact that each bit switch is made in the form of two CMOS transistors, the source 1520661 * of the first CMOS transistor is combined with the source of the second CMOS transistor and is the information input of the J bit switch, the gates of the first and second CMOS transistors are the first and second control inputs of the discharge switch, respectively, the drains of the first ed and second CMOS transistors are respectively the first and second bit switch outputs.