SU966887A1 - Digit type current converter - Google Patents

Description

The invention relates to the pulse technique and is intended for use in converters of a cyclic V code into an analog signal.

A current discharge converter (RPT) is known, which contains an inverting current repeater (JTP), a weight current generator (GW), a non-inverting current repeater (NIPT) and a switch, the control input of which is connected to the input code bus, the first output is connected to the input of the inverting repeater current, the output of which is connected to the output of the non-inverting current repeater and the output of the converter l.

The disadvantage of the RPT is low speed, since the conversion time 0 | is limited by the response time of the distributor. . :. ; . , /

The purpose of the invention is to increase the speed of RPT. The goal is achieved by the fact that in the bit converter the current is. ka containing an inverting current repeater, a weight generator; ka, non-inverting current repeater and switch, the control input of which is connected to the input bus

current, and the first output is connected with the input of the inverting current repeater, the output of which is connected to the output of the non-inverting current repeater and the output of the converter, the output of the weight current generator is connected to the input of the inverting current repeater, and with the first output of the switch, the second output of which is connected to the output

10 converter, and vhrd switch is connected to the analog input of the converter.

Figure 1 presents the block diagram of the proposed device; 2 a 15 embodiment.

The device contains input1 and output 2, switch 3, the control input of which is connected to input bus 4, the analog input is connected to input 1 of the RPT, and one of its outputs is connected to output 2 of the RPT. The second output of the switch 3 is connected to the inputs of NIPT 5, IPT b and the output of GWT 7i. The outputs of NIPT 5 and IPT 6 are connected to the output 2 of the RPT.

25

As it is known, when converting into an analog of a cyclic code, the value of the output current of the PST, depending on the value of the logic signal, must be equal to either the difference modulus, whether 30, bo, the sum of its input and weight currents. In the proposed RPT, the output current satisfies this requirement, the ec R € R / 2 wupt bhntspt when using switch 3, input 1 RPT is connected to output 2, and RR - - whrt hetVipt- vhnipt / 7 ftV MPT HF HM6T when input 1 RPT is connected to inputs NITP 5 and IPT b (Kvkipti Kvkhnipt-vkhi resistance of IPT b and NIPT 5, IPX RPT input current RPT, If-ef output current GWT 7, n - the number of bits of the converted binary-to-analog converter binary number). The discharge current converter operates as follows. When RPT 4 arrives at digital input 4, switch 3 connects in in 1 RTD to output 2. The output current HS 7 passes through IPT b, since its input resistance in this state of the switch is at least less than the input resistance of NIPT 5, The output current of the RPT in this case is equal to the sum of the input and weight currents. When O arrives at input 4, switch 3 connects input 1 of the RPT with a common entry point of IPT b, NIPT and GWT 7. The difference between input and weight currents passes through IPT b, when the weight current is greater than the input, or through NIPT 5 otherwise, therefore, the output current of the RPT has a constant direction, i.e. equal to the modulus of the difference between the input and load currents. The absence in the proposed RPT of the distributor, which would limit the action, ensures the achievement of the objective of the invention. In one of the possible variants and completeness of the proposed device (see, Fig. 2), a bipolar transistor connected according to the scheme with a common base of IPT b containing two bipolar transistors 8 and 9 of the same conductivity type is used as NIPT 5. the transistor in the NIPT 5. The emitter of the transistors 8 and 9 are interconnected and with the power source 10. The collector and the base of the transistor 8 are connected to the base of the transistor 9 and are the input of the IPT b. Transistor collector 9 - IPT output b. The potential of the emitters of transistors 8 and 9 exceeds the potential of the base of the transistor in NIPT 5 by the amount of voltage drop on the emitter junction of the transistor in NIPT 5 in its open state. The parallel connection of the emitter transitions of the transistors 8 and 9 ensures the equality of the bias voltages on them and, thus, the equality of the currents flowing through them and, therefore, through the input and output of the IPT. Depending on the position of the switch 3 and the ratio of the input and reference currents, either the transistor in NIPT 5 or transistors 8 and 9 is open, which ensures the necessary ratios of the input resistances of the IPT and NIPT. Forg / 1ula Invention A discharge current converter containing an inverting current follower, a weight TOKaJ generator, a non-inverting current repeater, and a switch whose control input is connected to the input code bus, and the first output is connected to the inverting current repeater input, the output of which is connected to the non-inverting output current and output of the converter, characterized in that, in order to increase speed, the output of the weight current generator is connected to the input of the inverting current repeater and from m switch output, the second output of which is connected to the output transducer and the input switch is connected to the analog input of the converter. Sources of information taken into account during the examination 1. USSR Author's Certificate for Application No. 2695721, cl. H 03 K 13/02, 12.12.78 (prototype).

Claims (1)

Claim A discharge current transformer containing an inverting 3θ current transformer, a weight generator ronaj a non-inverting current repeater and a switch whose control input is connected to the input bus (code, and the first output is connected to input 35 (the house of the inverting current repeater, the output of which is connected to the output of the non-inverting current repeater and the output of the converter, characterized in that, 40, in order to improve performance, the output of the weight current generator is connected to the input of the inverting current follower and to the first output switch Attic, the second output of which pod45 keys to the inverter output, and a switch input connected to the analog input of the converter.